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llvm-mirror/lib/CodeGen/SelectionDAG/TargetLowering.cpp
Matt Arsenault ccceacf068 DAG: Try scalarizing when expanding saturating add/sub 
In an upcoming AMDGPU patch, the scalar cases will be legal and vector
ops should be scalarized, rather than producing a long sequence of
vector ops which will also need to be scalarized.

Use a lazy heuristic that seems to work and improves the thumb2 MVE
test.
2020-07-16 14:05:16 -04:00

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//===-- TargetLowering.cpp - Implement the TargetLowering class -----------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This implements the TargetLowering class.
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/TargetLowering.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/CodeGen/CallingConvLower.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/KnownBits.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
#include "llvm/Target/TargetMachine.h"
#include <cctype>
using namespace llvm;
/// NOTE: The TargetMachine owns TLOF.
TargetLowering::TargetLowering(const TargetMachine &tm)
: TargetLoweringBase(tm) {}
const char *TargetLowering::getTargetNodeName(unsigned Opcode) const {
return nullptr;
}
bool TargetLowering::isPositionIndependent() const {
return getTargetMachine().isPositionIndependent();
}
/// Check whether a given call node is in tail position within its function. If
/// so, it sets Chain to the input chain of the tail call.
bool TargetLowering::isInTailCallPosition(SelectionDAG &DAG, SDNode *Node,
SDValue &Chain) const {
const Function &F = DAG.getMachineFunction().getFunction();
// First, check if tail calls have been disabled in this function.
if (F.getFnAttribute("disable-tail-calls").getValueAsString() == "true")
return false;
// Conservatively require the attributes of the call to match those of
// the return. Ignore NoAlias and NonNull because they don't affect the
// call sequence.
AttributeList CallerAttrs = F.getAttributes();
if (AttrBuilder(CallerAttrs, AttributeList::ReturnIndex)
.removeAttribute(Attribute::NoAlias)
.removeAttribute(Attribute::NonNull)
.hasAttributes())
return false;
// It's not safe to eliminate the sign / zero extension of the return value.
if (CallerAttrs.hasAttribute(AttributeList::ReturnIndex, Attribute::ZExt) ||
CallerAttrs.hasAttribute(AttributeList::ReturnIndex, Attribute::SExt))
return false;
// Check if the only use is a function return node.
return isUsedByReturnOnly(Node, Chain);
}
bool TargetLowering::parametersInCSRMatch(const MachineRegisterInfo &MRI,
const uint32_t *CallerPreservedMask,
const SmallVectorImpl<CCValAssign> &ArgLocs,
const SmallVectorImpl<SDValue> &OutVals) const {
for (unsigned I = 0, E = ArgLocs.size(); I != E; ++I) {
const CCValAssign &ArgLoc = ArgLocs[I];
if (!ArgLoc.isRegLoc())
continue;
MCRegister Reg = ArgLoc.getLocReg();
// Only look at callee saved registers.
if (MachineOperand::clobbersPhysReg(CallerPreservedMask, Reg))
continue;
// Check that we pass the value used for the caller.
// (We look for a CopyFromReg reading a virtual register that is used
// for the function live-in value of register Reg)
SDValue Value = OutVals[I];
if (Value->getOpcode() != ISD::CopyFromReg)
return false;
MCRegister ArgReg = cast<RegisterSDNode>(Value->getOperand(1))->getReg();
if (MRI.getLiveInPhysReg(ArgReg) != Reg)
return false;
}
return true;
}
/// Set CallLoweringInfo attribute flags based on a call instruction
/// and called function attributes.
void TargetLoweringBase::ArgListEntry::setAttributes(const CallBase *Call,
unsigned ArgIdx) {
IsSExt = Call->paramHasAttr(ArgIdx, Attribute::SExt);
IsZExt = Call->paramHasAttr(ArgIdx, Attribute::ZExt);
IsInReg = Call->paramHasAttr(ArgIdx, Attribute::InReg);
IsSRet = Call->paramHasAttr(ArgIdx, Attribute::StructRet);
IsNest = Call->paramHasAttr(ArgIdx, Attribute::Nest);
IsByVal = Call->paramHasAttr(ArgIdx, Attribute::ByVal);
IsPreallocated = Call->paramHasAttr(ArgIdx, Attribute::Preallocated);
IsInAlloca = Call->paramHasAttr(ArgIdx, Attribute::InAlloca);
IsReturned = Call->paramHasAttr(ArgIdx, Attribute::Returned);
IsSwiftSelf = Call->paramHasAttr(ArgIdx, Attribute::SwiftSelf);
IsSwiftError = Call->paramHasAttr(ArgIdx, Attribute::SwiftError);
Alignment = Call->getParamAlign(ArgIdx);
ByValType = nullptr;
if (IsByVal)
ByValType = Call->getParamByValType(ArgIdx);
PreallocatedType = nullptr;
if (IsPreallocated)
PreallocatedType = Call->getParamPreallocatedType(ArgIdx);
}
/// Generate a libcall taking the given operands as arguments and returning a
/// result of type RetVT.
std::pair<SDValue, SDValue>
TargetLowering::makeLibCall(SelectionDAG &DAG, RTLIB::Libcall LC, EVT RetVT,
ArrayRef<SDValue> Ops,
MakeLibCallOptions CallOptions,
const SDLoc &dl,
SDValue InChain) const {
if (!InChain)
InChain = DAG.getEntryNode();
TargetLowering::ArgListTy Args;
Args.reserve(Ops.size());
TargetLowering::ArgListEntry Entry;
for (unsigned i = 0; i < Ops.size(); ++i) {
SDValue NewOp = Ops[i];
Entry.Node = NewOp;
Entry.Ty = Entry.Node.getValueType().getTypeForEVT(*DAG.getContext());
Entry.IsSExt = shouldSignExtendTypeInLibCall(NewOp.getValueType(),
CallOptions.IsSExt);
Entry.IsZExt = !Entry.IsSExt;
if (CallOptions.IsSoften &&
!shouldExtendTypeInLibCall(CallOptions.OpsVTBeforeSoften[i])) {
Entry.IsSExt = Entry.IsZExt = false;
}
Args.push_back(Entry);
}
if (LC == RTLIB::UNKNOWN_LIBCALL)
report_fatal_error("Unsupported library call operation!");
SDValue Callee = DAG.getExternalSymbol(getLibcallName(LC),
getPointerTy(DAG.getDataLayout()));
Type *RetTy = RetVT.getTypeForEVT(*DAG.getContext());
TargetLowering::CallLoweringInfo CLI(DAG);
bool signExtend = shouldSignExtendTypeInLibCall(RetVT, CallOptions.IsSExt);
bool zeroExtend = !signExtend;
if (CallOptions.IsSoften &&
!shouldExtendTypeInLibCall(CallOptions.RetVTBeforeSoften)) {
signExtend = zeroExtend = false;
}
CLI.setDebugLoc(dl)
.setChain(InChain)
.setLibCallee(getLibcallCallingConv(LC), RetTy, Callee, std::move(Args))
.setNoReturn(CallOptions.DoesNotReturn)
.setDiscardResult(!CallOptions.IsReturnValueUsed)
.setIsPostTypeLegalization(CallOptions.IsPostTypeLegalization)
.setSExtResult(signExtend)
.setZExtResult(zeroExtend);
return LowerCallTo(CLI);
}
bool TargetLowering::findOptimalMemOpLowering(
std::vector<EVT> &MemOps, unsigned Limit, const MemOp &Op, unsigned DstAS,
unsigned SrcAS, const AttributeList &FuncAttributes) const {
if (Op.isMemcpyWithFixedDstAlign() && Op.getSrcAlign() < Op.getDstAlign())
return false;
EVT VT = getOptimalMemOpType(Op, FuncAttributes);
if (VT == MVT::Other) {
// Use the largest integer type whose alignment constraints are satisfied.
// We only need to check DstAlign here as SrcAlign is always greater or
// equal to DstAlign (or zero).
VT = MVT::i64;
if (Op.isFixedDstAlign())
while (
Op.getDstAlign() < (VT.getSizeInBits() / 8) &&
!allowsMisalignedMemoryAccesses(VT, DstAS, Op.getDstAlign().value()))
VT = (MVT::SimpleValueType)(VT.getSimpleVT().SimpleTy - 1);
assert(VT.isInteger());
// Find the largest legal integer type.
MVT LVT = MVT::i64;
while (!isTypeLegal(LVT))
LVT = (MVT::SimpleValueType)(LVT.SimpleTy - 1);
assert(LVT.isInteger());
// If the type we've chosen is larger than the largest legal integer type
// then use that instead.
if (VT.bitsGT(LVT))
VT = LVT;
}
unsigned NumMemOps = 0;
uint64_t Size = Op.size();
while (Size) {
unsigned VTSize = VT.getSizeInBits() / 8;
while (VTSize > Size) {
// For now, only use non-vector load / store's for the left-over pieces.
EVT NewVT = VT;
unsigned NewVTSize;
bool Found = false;
if (VT.isVector() || VT.isFloatingPoint()) {
NewVT = (VT.getSizeInBits() > 64) ? MVT::i64 : MVT::i32;
if (isOperationLegalOrCustom(ISD::STORE, NewVT) &&
isSafeMemOpType(NewVT.getSimpleVT()))
Found = true;
else if (NewVT == MVT::i64 &&
isOperationLegalOrCustom(ISD::STORE, MVT::f64) &&
isSafeMemOpType(MVT::f64)) {
// i64 is usually not legal on 32-bit targets, but f64 may be.
NewVT = MVT::f64;
Found = true;
}
}
if (!Found) {
do {
NewVT = (MVT::SimpleValueType)(NewVT.getSimpleVT().SimpleTy - 1);
if (NewVT == MVT::i8)
break;
} while (!isSafeMemOpType(NewVT.getSimpleVT()));
}
NewVTSize = NewVT.getSizeInBits() / 8;
// If the new VT cannot cover all of the remaining bits, then consider
// issuing a (or a pair of) unaligned and overlapping load / store.
bool Fast;
if (NumMemOps && Op.allowOverlap() && NewVTSize < Size &&
allowsMisalignedMemoryAccesses(
VT, DstAS, Op.isFixedDstAlign() ? Op.getDstAlign().value() : 0,
MachineMemOperand::MONone, &Fast) &&
Fast)
VTSize = Size;
else {
VT = NewVT;
VTSize = NewVTSize;
}
}
if (++NumMemOps > Limit)
return false;
MemOps.push_back(VT);
Size -= VTSize;
}
return true;
}
/// Soften the operands of a comparison. This code is shared among BR_CC,
/// SELECT_CC, and SETCC handlers.
void TargetLowering::softenSetCCOperands(SelectionDAG &DAG, EVT VT,
SDValue &NewLHS, SDValue &NewRHS,
ISD::CondCode &CCCode,
const SDLoc &dl, const SDValue OldLHS,
const SDValue OldRHS) const {
SDValue Chain;
return softenSetCCOperands(DAG, VT, NewLHS, NewRHS, CCCode, dl, OldLHS,
OldRHS, Chain);
}
void TargetLowering::softenSetCCOperands(SelectionDAG &DAG, EVT VT,
SDValue &NewLHS, SDValue &NewRHS,
ISD::CondCode &CCCode,
const SDLoc &dl, const SDValue OldLHS,
const SDValue OldRHS,
SDValue &Chain,
bool IsSignaling) const {
// FIXME: Currently we cannot really respect all IEEE predicates due to libgcc
// not supporting it. We can update this code when libgcc provides such
// functions.
assert((VT == MVT::f32 || VT == MVT::f64 || VT == MVT::f128 || VT == MVT::ppcf128)
&& "Unsupported setcc type!");
// Expand into one or more soft-fp libcall(s).
RTLIB::Libcall LC1 = RTLIB::UNKNOWN_LIBCALL, LC2 = RTLIB::UNKNOWN_LIBCALL;
bool ShouldInvertCC = false;
switch (CCCode) {
case ISD::SETEQ:
case ISD::SETOEQ:
LC1 = (VT == MVT::f32) ? RTLIB::OEQ_F32 :
(VT == MVT::f64) ? RTLIB::OEQ_F64 :
(VT == MVT::f128) ? RTLIB::OEQ_F128 : RTLIB::OEQ_PPCF128;
break;
case ISD::SETNE:
case ISD::SETUNE:
LC1 = (VT == MVT::f32) ? RTLIB::UNE_F32 :
(VT == MVT::f64) ? RTLIB::UNE_F64 :
(VT == MVT::f128) ? RTLIB::UNE_F128 : RTLIB::UNE_PPCF128;
break;
case ISD::SETGE:
case ISD::SETOGE:
LC1 = (VT == MVT::f32) ? RTLIB::OGE_F32 :
(VT == MVT::f64) ? RTLIB::OGE_F64 :
(VT == MVT::f128) ? RTLIB::OGE_F128 : RTLIB::OGE_PPCF128;
break;
case ISD::SETLT:
case ISD::SETOLT:
LC1 = (VT == MVT::f32) ? RTLIB::OLT_F32 :
(VT == MVT::f64) ? RTLIB::OLT_F64 :
(VT == MVT::f128) ? RTLIB::OLT_F128 : RTLIB::OLT_PPCF128;
break;
case ISD::SETLE:
case ISD::SETOLE:
LC1 = (VT == MVT::f32) ? RTLIB::OLE_F32 :
(VT == MVT::f64) ? RTLIB::OLE_F64 :
(VT == MVT::f128) ? RTLIB::OLE_F128 : RTLIB::OLE_PPCF128;
break;
case ISD::SETGT:
case ISD::SETOGT:
LC1 = (VT == MVT::f32) ? RTLIB::OGT_F32 :
(VT == MVT::f64) ? RTLIB::OGT_F64 :
(VT == MVT::f128) ? RTLIB::OGT_F128 : RTLIB::OGT_PPCF128;
break;
case ISD::SETO:
ShouldInvertCC = true;
LLVM_FALLTHROUGH;
case ISD::SETUO:
LC1 = (VT == MVT::f32) ? RTLIB::UO_F32 :
(VT == MVT::f64) ? RTLIB::UO_F64 :
(VT == MVT::f128) ? RTLIB::UO_F128 : RTLIB::UO_PPCF128;
break;
case ISD::SETONE:
// SETONE = O && UNE
ShouldInvertCC = true;
LLVM_FALLTHROUGH;
case ISD::SETUEQ:
LC1 = (VT == MVT::f32) ? RTLIB::UO_F32 :
(VT == MVT::f64) ? RTLIB::UO_F64 :
(VT == MVT::f128) ? RTLIB::UO_F128 : RTLIB::UO_PPCF128;
LC2 = (VT == MVT::f32) ? RTLIB::OEQ_F32 :
(VT == MVT::f64) ? RTLIB::OEQ_F64 :
(VT == MVT::f128) ? RTLIB::OEQ_F128 : RTLIB::OEQ_PPCF128;
break;
default:
// Invert CC for unordered comparisons
ShouldInvertCC = true;
switch (CCCode) {
case ISD::SETULT:
LC1 = (VT == MVT::f32) ? RTLIB::OGE_F32 :
(VT == MVT::f64) ? RTLIB::OGE_F64 :
(VT == MVT::f128) ? RTLIB::OGE_F128 : RTLIB::OGE_PPCF128;
break;
case ISD::SETULE:
LC1 = (VT == MVT::f32) ? RTLIB::OGT_F32 :
(VT == MVT::f64) ? RTLIB::OGT_F64 :
(VT == MVT::f128) ? RTLIB::OGT_F128 : RTLIB::OGT_PPCF128;
break;
case ISD::SETUGT:
LC1 = (VT == MVT::f32) ? RTLIB::OLE_F32 :
(VT == MVT::f64) ? RTLIB::OLE_F64 :
(VT == MVT::f128) ? RTLIB::OLE_F128 : RTLIB::OLE_PPCF128;
break;
case ISD::SETUGE:
LC1 = (VT == MVT::f32) ? RTLIB::OLT_F32 :
(VT == MVT::f64) ? RTLIB::OLT_F64 :
(VT == MVT::f128) ? RTLIB::OLT_F128 : RTLIB::OLT_PPCF128;
break;
default: llvm_unreachable("Do not know how to soften this setcc!");
}
}
// Use the target specific return value for comparions lib calls.
EVT RetVT = getCmpLibcallReturnType();
SDValue Ops[2] = {NewLHS, NewRHS};
TargetLowering::MakeLibCallOptions CallOptions;
EVT OpsVT[2] = { OldLHS.getValueType(),
OldRHS.getValueType() };
CallOptions.setTypeListBeforeSoften(OpsVT, RetVT, true);
auto Call = makeLibCall(DAG, LC1, RetVT, Ops, CallOptions, dl, Chain);
NewLHS = Call.first;
NewRHS = DAG.getConstant(0, dl, RetVT);
CCCode = getCmpLibcallCC(LC1);
if (ShouldInvertCC) {
assert(RetVT.isInteger());
CCCode = getSetCCInverse(CCCode, RetVT);
}
if (LC2 == RTLIB::UNKNOWN_LIBCALL) {
// Update Chain.
Chain = Call.second;
} else {
EVT SetCCVT =
getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(), RetVT);
SDValue Tmp = DAG.getSetCC(dl, SetCCVT, NewLHS, NewRHS, CCCode);
auto Call2 = makeLibCall(DAG, LC2, RetVT, Ops, CallOptions, dl, Chain);
CCCode = getCmpLibcallCC(LC2);
if (ShouldInvertCC)
CCCode = getSetCCInverse(CCCode, RetVT);
NewLHS = DAG.getSetCC(dl, SetCCVT, Call2.first, NewRHS, CCCode);
if (Chain)
Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Call.second,
Call2.second);
NewLHS = DAG.getNode(ShouldInvertCC ? ISD::AND : ISD::OR, dl,
Tmp.getValueType(), Tmp, NewLHS);
NewRHS = SDValue();
}
}
/// Return the entry encoding for a jump table in the current function. The
/// returned value is a member of the MachineJumpTableInfo::JTEntryKind enum.
unsigned TargetLowering::getJumpTableEncoding() const {
// In non-pic modes, just use the address of a block.
if (!isPositionIndependent())
return MachineJumpTableInfo::EK_BlockAddress;
// In PIC mode, if the target supports a GPRel32 directive, use it.
if (getTargetMachine().getMCAsmInfo()->getGPRel32Directive() != nullptr)
return MachineJumpTableInfo::EK_GPRel32BlockAddress;
// Otherwise, use a label difference.
return MachineJumpTableInfo::EK_LabelDifference32;
}
SDValue TargetLowering::getPICJumpTableRelocBase(SDValue Table,
SelectionDAG &DAG) const {
// If our PIC model is GP relative, use the global offset table as the base.
unsigned JTEncoding = getJumpTableEncoding();
if ((JTEncoding == MachineJumpTableInfo::EK_GPRel64BlockAddress) ||
(JTEncoding == MachineJumpTableInfo::EK_GPRel32BlockAddress))
return DAG.getGLOBAL_OFFSET_TABLE(getPointerTy(DAG.getDataLayout()));
return Table;
}
/// This returns the relocation base for the given PIC jumptable, the same as
/// getPICJumpTableRelocBase, but as an MCExpr.
const MCExpr *
TargetLowering::getPICJumpTableRelocBaseExpr(const MachineFunction *MF,
unsigned JTI,MCContext &Ctx) const{
// The normal PIC reloc base is the label at the start of the jump table.
return MCSymbolRefExpr::create(MF->getJTISymbol(JTI, Ctx), Ctx);
}
bool
TargetLowering::isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const {
const TargetMachine &TM = getTargetMachine();
const GlobalValue *GV = GA->getGlobal();
// If the address is not even local to this DSO we will have to load it from
// a got and then add the offset.
if (!TM.shouldAssumeDSOLocal(*GV->getParent(), GV))
return false;
// If the code is position independent we will have to add a base register.
if (isPositionIndependent())
return false;
// Otherwise we can do it.
return true;
}
//===----------------------------------------------------------------------===//
// Optimization Methods
//===----------------------------------------------------------------------===//
/// If the specified instruction has a constant integer operand and there are
/// bits set in that constant that are not demanded, then clear those bits and
/// return true.
bool TargetLowering::ShrinkDemandedConstant(SDValue Op,
const APInt &DemandedBits,
const APInt &DemandedElts,
TargetLoweringOpt &TLO) const {
SDLoc DL(Op);
unsigned Opcode = Op.getOpcode();
// Do target-specific constant optimization.
if (targetShrinkDemandedConstant(Op, DemandedBits, DemandedElts, TLO))
return TLO.New.getNode();
// FIXME: ISD::SELECT, ISD::SELECT_CC
switch (Opcode) {
default:
break;
case ISD::XOR:
case ISD::AND:
case ISD::OR: {
auto *Op1C = dyn_cast<ConstantSDNode>(Op.getOperand(1));
if (!Op1C)
return false;
// If this is a 'not' op, don't touch it because that's a canonical form.
const APInt &C = Op1C->getAPIntValue();
if (Opcode == ISD::XOR && DemandedBits.isSubsetOf(C))
return false;
if (!C.isSubsetOf(DemandedBits)) {
EVT VT = Op.getValueType();
SDValue NewC = TLO.DAG.getConstant(DemandedBits & C, DL, VT);
SDValue NewOp = TLO.DAG.getNode(Opcode, DL, VT, Op.getOperand(0), NewC);
return TLO.CombineTo(Op, NewOp);
}
break;
}
}
return false;
}
bool TargetLowering::ShrinkDemandedConstant(SDValue Op,
const APInt &DemandedBits,
TargetLoweringOpt &TLO) const {
EVT VT = Op.getValueType();
APInt DemandedElts = VT.isVector()
? APInt::getAllOnesValue(VT.getVectorNumElements())
: APInt(1, 1);
return ShrinkDemandedConstant(Op, DemandedBits, DemandedElts, TLO);
}
/// Convert x+y to (VT)((SmallVT)x+(SmallVT)y) if the casts are free.
/// This uses isZExtFree and ZERO_EXTEND for the widening cast, but it could be
/// generalized for targets with other types of implicit widening casts.
bool TargetLowering::ShrinkDemandedOp(SDValue Op, unsigned BitWidth,
const APInt &Demanded,
TargetLoweringOpt &TLO) const {
assert(Op.getNumOperands() == 2 &&
"ShrinkDemandedOp only supports binary operators!");
assert(Op.getNode()->getNumValues() == 1 &&
"ShrinkDemandedOp only supports nodes with one result!");
SelectionDAG &DAG = TLO.DAG;
SDLoc dl(Op);
// Early return, as this function cannot handle vector types.
if (Op.getValueType().isVector())
return false;
// Don't do this if the node has another user, which may require the
// full value.
if (!Op.getNode()->hasOneUse())
return false;
// Search for the smallest integer type with free casts to and from
// Op's type. For expedience, just check power-of-2 integer types.
const TargetLowering &TLI = DAG.getTargetLoweringInfo();
unsigned DemandedSize = Demanded.getActiveBits();
unsigned SmallVTBits = DemandedSize;
if (!isPowerOf2_32(SmallVTBits))
SmallVTBits = NextPowerOf2(SmallVTBits);
for (; SmallVTBits < BitWidth; SmallVTBits = NextPowerOf2(SmallVTBits)) {
EVT SmallVT = EVT::getIntegerVT(*DAG.getContext(), SmallVTBits);
if (TLI.isTruncateFree(Op.getValueType(), SmallVT) &&
TLI.isZExtFree(SmallVT, Op.getValueType())) {
// We found a type with free casts.
SDValue X = DAG.getNode(
Op.getOpcode(), dl, SmallVT,
DAG.getNode(ISD::TRUNCATE, dl, SmallVT, Op.getOperand(0)),
DAG.getNode(ISD::TRUNCATE, dl, SmallVT, Op.getOperand(1)));
assert(DemandedSize <= SmallVTBits && "Narrowed below demanded bits?");
SDValue Z = DAG.getNode(ISD::ANY_EXTEND, dl, Op.getValueType(), X);
return TLO.CombineTo(Op, Z);
}
}
return false;
}
bool TargetLowering::SimplifyDemandedBits(SDValue Op, const APInt &DemandedBits,
DAGCombinerInfo &DCI) const {
SelectionDAG &DAG = DCI.DAG;
TargetLoweringOpt TLO(DAG, !DCI.isBeforeLegalize(),
!DCI.isBeforeLegalizeOps());
KnownBits Known;
bool Simplified = SimplifyDemandedBits(Op, DemandedBits, Known, TLO);
if (Simplified) {
DCI.AddToWorklist(Op.getNode());
DCI.CommitTargetLoweringOpt(TLO);
}
return Simplified;
}
bool TargetLowering::SimplifyDemandedBits(SDValue Op, const APInt &DemandedBits,
KnownBits &Known,
TargetLoweringOpt &TLO,
unsigned Depth,
bool AssumeSingleUse) const {
EVT VT = Op.getValueType();
// TODO: We can probably do more work on calculating the known bits and
// simplifying the operations for scalable vectors, but for now we just
// bail out.
if (VT.isScalableVector()) {
// Pretend we don't know anything for now.
Known = KnownBits(DemandedBits.getBitWidth());
return false;
}
APInt DemandedElts = VT.isVector()
? APInt::getAllOnesValue(VT.getVectorNumElements())
: APInt(1, 1);
return SimplifyDemandedBits(Op, DemandedBits, DemandedElts, Known, TLO, Depth,
AssumeSingleUse);
}
// TODO: Can we merge SelectionDAG::GetDemandedBits into this?
// TODO: Under what circumstances can we create nodes? Constant folding?
SDValue TargetLowering::SimplifyMultipleUseDemandedBits(
SDValue Op, const APInt &DemandedBits, const APInt &DemandedElts,
SelectionDAG &DAG, unsigned Depth) const {
// Limit search depth.
if (Depth >= SelectionDAG::MaxRecursionDepth)
return SDValue();
// Ignore UNDEFs.
if (Op.isUndef())
return SDValue();
// Not demanding any bits/elts from Op.
if (DemandedBits == 0 || DemandedElts == 0)
return DAG.getUNDEF(Op.getValueType());
unsigned NumElts = DemandedElts.getBitWidth();
unsigned BitWidth = DemandedBits.getBitWidth();
KnownBits LHSKnown, RHSKnown;
switch (Op.getOpcode()) {
case ISD::BITCAST: {
SDValue Src = peekThroughBitcasts(Op.getOperand(0));
EVT SrcVT = Src.getValueType();
EVT DstVT = Op.getValueType();
if (SrcVT == DstVT)
return Src;
unsigned NumSrcEltBits = SrcVT.getScalarSizeInBits();
unsigned NumDstEltBits = DstVT.getScalarSizeInBits();
if (NumSrcEltBits == NumDstEltBits)
if (SDValue V = SimplifyMultipleUseDemandedBits(
Src, DemandedBits, DemandedElts, DAG, Depth + 1))
return DAG.getBitcast(DstVT, V);
// TODO - bigendian once we have test coverage.
if (SrcVT.isVector() && (NumDstEltBits % NumSrcEltBits) == 0 &&
DAG.getDataLayout().isLittleEndian()) {
unsigned Scale = NumDstEltBits / NumSrcEltBits;
unsigned NumSrcElts = SrcVT.getVectorNumElements();
APInt DemandedSrcBits = APInt::getNullValue(NumSrcEltBits);
APInt DemandedSrcElts = APInt::getNullValue(NumSrcElts);
for (unsigned i = 0; i != Scale; ++i) {
unsigned Offset = i * NumSrcEltBits;
APInt Sub = DemandedBits.extractBits(NumSrcEltBits, Offset);
if (!Sub.isNullValue()) {
DemandedSrcBits |= Sub;
for (unsigned j = 0; j != NumElts; ++j)
if (DemandedElts[j])
DemandedSrcElts.setBit((j * Scale) + i);
}
}
if (SDValue V = SimplifyMultipleUseDemandedBits(
Src, DemandedSrcBits, DemandedSrcElts, DAG, Depth + 1))
return DAG.getBitcast(DstVT, V);
}
// TODO - bigendian once we have test coverage.
if ((NumSrcEltBits % NumDstEltBits) == 0 &&
DAG.getDataLayout().isLittleEndian()) {
unsigned Scale = NumSrcEltBits / NumDstEltBits;
unsigned NumSrcElts = SrcVT.isVector() ? SrcVT.getVectorNumElements() : 1;
APInt DemandedSrcBits = APInt::getNullValue(NumSrcEltBits);
APInt DemandedSrcElts = APInt::getNullValue(NumSrcElts);
for (unsigned i = 0; i != NumElts; ++i)
if (DemandedElts[i]) {
unsigned Offset = (i % Scale) * NumDstEltBits;
DemandedSrcBits.insertBits(DemandedBits, Offset);
DemandedSrcElts.setBit(i / Scale);
}
if (SDValue V = SimplifyMultipleUseDemandedBits(
Src, DemandedSrcBits, DemandedSrcElts, DAG, Depth + 1))
return DAG.getBitcast(DstVT, V);
}
break;
}
case ISD::AND: {
LHSKnown = DAG.computeKnownBits(Op.getOperand(0), DemandedElts, Depth + 1);
RHSKnown = DAG.computeKnownBits(Op.getOperand(1), DemandedElts, Depth + 1);
// If all of the demanded bits are known 1 on one side, return the other.
// These bits cannot contribute to the result of the 'and' in this
// context.
if (DemandedBits.isSubsetOf(LHSKnown.Zero | RHSKnown.One))
return Op.getOperand(0);
if (DemandedBits.isSubsetOf(RHSKnown.Zero | LHSKnown.One))
return Op.getOperand(1);
break;
}
case ISD::OR: {
LHSKnown = DAG.computeKnownBits(Op.getOperand(0), DemandedElts, Depth + 1);
RHSKnown = DAG.computeKnownBits(Op.getOperand(1), DemandedElts, Depth + 1);
// If all of the demanded bits are known zero on one side, return the
// other. These bits cannot contribute to the result of the 'or' in this
// context.
if (DemandedBits.isSubsetOf(LHSKnown.One | RHSKnown.Zero))
return Op.getOperand(0);
if (DemandedBits.isSubsetOf(RHSKnown.One | LHSKnown.Zero))
return Op.getOperand(1);
break;
}
case ISD::XOR: {
LHSKnown = DAG.computeKnownBits(Op.getOperand(0), DemandedElts, Depth + 1);
RHSKnown = DAG.computeKnownBits(Op.getOperand(1), DemandedElts, Depth + 1);
// If all of the demanded bits are known zero on one side, return the
// other.
if (DemandedBits.isSubsetOf(RHSKnown.Zero))
return Op.getOperand(0);
if (DemandedBits.isSubsetOf(LHSKnown.Zero))
return Op.getOperand(1);
break;
}
case ISD::SHL: {
// If we are only demanding sign bits then we can use the shift source
// directly.
if (const APInt *MaxSA =
DAG.getValidMaximumShiftAmountConstant(Op, DemandedElts)) {
SDValue Op0 = Op.getOperand(0);
unsigned ShAmt = MaxSA->getZExtValue();
unsigned NumSignBits =
DAG.ComputeNumSignBits(Op0, DemandedElts, Depth + 1);
unsigned UpperDemandedBits = BitWidth - DemandedBits.countTrailingZeros();
if (NumSignBits > ShAmt && (NumSignBits - ShAmt) >= (UpperDemandedBits))
return Op0;
}
break;
}
case ISD::SETCC: {
SDValue Op0 = Op.getOperand(0);
SDValue Op1 = Op.getOperand(1);
ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(2))->get();
// If (1) we only need the sign-bit, (2) the setcc operands are the same
// width as the setcc result, and (3) the result of a setcc conforms to 0 or
// -1, we may be able to bypass the setcc.
if (DemandedBits.isSignMask() &&
Op0.getScalarValueSizeInBits() == BitWidth &&
getBooleanContents(Op0.getValueType()) ==
BooleanContent::ZeroOrNegativeOneBooleanContent) {
// If we're testing X < 0, then this compare isn't needed - just use X!
// FIXME: We're limiting to integer types here, but this should also work
// if we don't care about FP signed-zero. The use of SETLT with FP means
// that we don't care about NaNs.
if (CC == ISD::SETLT && Op1.getValueType().isInteger() &&
(isNullConstant(Op1) || ISD::isBuildVectorAllZeros(Op1.getNode())))
return Op0;
}
break;
}
case ISD::SIGN_EXTEND_INREG: {
// If none of the extended bits are demanded, eliminate the sextinreg.
SDValue Op0 = Op.getOperand(0);
EVT ExVT = cast<VTSDNode>(Op.getOperand(1))->getVT();
unsigned ExBits = ExVT.getScalarSizeInBits();
if (DemandedBits.getActiveBits() <= ExBits)
return Op0;
// If the input is already sign extended, just drop the extension.
unsigned NumSignBits = DAG.ComputeNumSignBits(Op0, DemandedElts, Depth + 1);
if (NumSignBits >= (BitWidth - ExBits + 1))
return Op0;
break;
}
case ISD::ANY_EXTEND_VECTOR_INREG:
case ISD::SIGN_EXTEND_VECTOR_INREG:
case ISD::ZERO_EXTEND_VECTOR_INREG: {
// If we only want the lowest element and none of extended bits, then we can
// return the bitcasted source vector.
SDValue Src = Op.getOperand(0);
EVT SrcVT = Src.getValueType();
EVT DstVT = Op.getValueType();
if (DemandedElts == 1 && DstVT.getSizeInBits() == SrcVT.getSizeInBits() &&
DAG.getDataLayout().isLittleEndian() &&
DemandedBits.getActiveBits() <= SrcVT.getScalarSizeInBits()) {
return DAG.getBitcast(DstVT, Src);
}
break;
}
case ISD::INSERT_VECTOR_ELT: {
// If we don't demand the inserted element, return the base vector.
SDValue Vec = Op.getOperand(0);
auto *CIdx = dyn_cast<ConstantSDNode>(Op.getOperand(2));
EVT VecVT = Vec.getValueType();
if (CIdx && CIdx->getAPIntValue().ult(VecVT.getVectorNumElements()) &&
!DemandedElts[CIdx->getZExtValue()])
return Vec;
break;
}
case ISD::INSERT_SUBVECTOR: {
// If we don't demand the inserted subvector, return the base vector.
SDValue Vec = Op.getOperand(0);
SDValue Sub = Op.getOperand(1);
uint64_t Idx = Op.getConstantOperandVal(2);
unsigned NumSubElts = Sub.getValueType().getVectorNumElements();
if (DemandedElts.extractBits(NumSubElts, Idx) == 0)
return Vec;
break;
}
case ISD::VECTOR_SHUFFLE: {
ArrayRef<int> ShuffleMask = cast<ShuffleVectorSDNode>(Op)->getMask();
// If all the demanded elts are from one operand and are inline,
// then we can use the operand directly.
bool AllUndef = true, IdentityLHS = true, IdentityRHS = true;
for (unsigned i = 0; i != NumElts; ++i) {
int M = ShuffleMask[i];
if (M < 0 || !DemandedElts[i])
continue;
AllUndef = false;
IdentityLHS &= (M == (int)i);
IdentityRHS &= ((M - NumElts) == i);
}
if (AllUndef)
return DAG.getUNDEF(Op.getValueType());
if (IdentityLHS)
return Op.getOperand(0);
if (IdentityRHS)
return Op.getOperand(1);
break;
}
default:
if (Op.getOpcode() >= ISD::BUILTIN_OP_END)
if (SDValue V = SimplifyMultipleUseDemandedBitsForTargetNode(
Op, DemandedBits, DemandedElts, DAG, Depth))
return V;
break;
}
return SDValue();
}
SDValue TargetLowering::SimplifyMultipleUseDemandedBits(
SDValue Op, const APInt &DemandedBits, SelectionDAG &DAG,
unsigned Depth) const {
EVT VT = Op.getValueType();
APInt DemandedElts = VT.isVector()
? APInt::getAllOnesValue(VT.getVectorNumElements())
: APInt(1, 1);
return SimplifyMultipleUseDemandedBits(Op, DemandedBits, DemandedElts, DAG,
Depth);
}
SDValue TargetLowering::SimplifyMultipleUseDemandedVectorElts(
SDValue Op, const APInt &DemandedElts, SelectionDAG &DAG,
unsigned Depth) const {
APInt DemandedBits = APInt::getAllOnesValue(Op.getScalarValueSizeInBits());
return SimplifyMultipleUseDemandedBits(Op, DemandedBits, DemandedElts, DAG,
Depth);
}
/// Look at Op. At this point, we know that only the OriginalDemandedBits of the
/// result of Op are ever used downstream. If we can use this information to
/// simplify Op, create a new simplified DAG node and return true, returning the
/// original and new nodes in Old and New. Otherwise, analyze the expression and
/// return a mask of Known bits for the expression (used to simplify the
/// caller). The Known bits may only be accurate for those bits in the
/// OriginalDemandedBits and OriginalDemandedElts.
bool TargetLowering::SimplifyDemandedBits(
SDValue Op, const APInt &OriginalDemandedBits,
const APInt &OriginalDemandedElts, KnownBits &Known, TargetLoweringOpt &TLO,
unsigned Depth, bool AssumeSingleUse) const {
unsigned BitWidth = OriginalDemandedBits.getBitWidth();
assert(Op.getScalarValueSizeInBits() == BitWidth &&
"Mask size mismatches value type size!");
// Don't know anything.
Known = KnownBits(BitWidth);
// TODO: We can probably do more work on calculating the known bits and
// simplifying the operations for scalable vectors, but for now we just
// bail out.
if (Op.getValueType().isScalableVector())
return false;
unsigned NumElts = OriginalDemandedElts.getBitWidth();
assert((!Op.getValueType().isVector() ||
NumElts == Op.getValueType().getVectorNumElements()) &&
"Unexpected vector size");
APInt DemandedBits = OriginalDemandedBits;
APInt DemandedElts = OriginalDemandedElts;
SDLoc dl(Op);
auto &DL = TLO.DAG.getDataLayout();
// Undef operand.
if (Op.isUndef())
return false;
if (Op.getOpcode() == ISD::Constant) {
// We know all of the bits for a constant!
Known.One = cast<ConstantSDNode>(Op)->getAPIntValue();
Known.Zero = ~Known.One;
return false;
}
// Other users may use these bits.
EVT VT = Op.getValueType();
if (!Op.getNode()->hasOneUse() && !AssumeSingleUse) {
if (Depth != 0) {
// If not at the root, Just compute the Known bits to
// simplify things downstream.
Known = TLO.DAG.computeKnownBits(Op, DemandedElts, Depth);
return false;
}
// If this is the root being simplified, allow it to have multiple uses,
// just set the DemandedBits/Elts to all bits.
DemandedBits = APInt::getAllOnesValue(BitWidth);
DemandedElts = APInt::getAllOnesValue(NumElts);
} else if (OriginalDemandedBits == 0 || OriginalDemandedElts == 0) {
// Not demanding any bits/elts from Op.
return TLO.CombineTo(Op, TLO.DAG.getUNDEF(VT));
} else if (Depth >= SelectionDAG::MaxRecursionDepth) {
// Limit search depth.
return false;
}
KnownBits Known2;
switch (Op.getOpcode()) {
case ISD::TargetConstant:
llvm_unreachable("Can't simplify this node");
case ISD::SCALAR_TO_VECTOR: {
if (!DemandedElts[0])
return TLO.CombineTo(Op, TLO.DAG.getUNDEF(VT));
KnownBits SrcKnown;
SDValue Src = Op.getOperand(0);
unsigned SrcBitWidth = Src.getScalarValueSizeInBits();
APInt SrcDemandedBits = DemandedBits.zextOrSelf(SrcBitWidth);
if (SimplifyDemandedBits(Src, SrcDemandedBits, SrcKnown, TLO, Depth + 1))
return true;
// Upper elements are undef, so only get the knownbits if we just demand
// the bottom element.
if (DemandedElts == 1)
Known = SrcKnown.anyextOrTrunc(BitWidth);
break;
}
case ISD::BUILD_VECTOR:
// Collect the known bits that are shared by every demanded element.
// TODO: Call SimplifyDemandedBits for non-constant demanded elements.
Known = TLO.DAG.computeKnownBits(Op, DemandedElts, Depth);
return false; // Don't fall through, will infinitely loop.
case ISD::LOAD: {
LoadSDNode *LD = cast<LoadSDNode>(Op);
if (getTargetConstantFromLoad(LD)) {
Known = TLO.DAG.computeKnownBits(Op, DemandedElts, Depth);
return false; // Don't fall through, will infinitely loop.
} else if (ISD::isZEXTLoad(Op.getNode()) && Op.getResNo() == 0) {
// If this is a ZEXTLoad and we are looking at the loaded value.
EVT MemVT = LD->getMemoryVT();
unsigned MemBits = MemVT.getScalarSizeInBits();
Known.Zero.setBitsFrom(MemBits);
return false; // Don't fall through, will infinitely loop.
}
break;
}
case ISD::INSERT_VECTOR_ELT: {
SDValue Vec = Op.getOperand(0);
SDValue Scl = Op.getOperand(1);
auto *CIdx = dyn_cast<ConstantSDNode>(Op.getOperand(2));
EVT VecVT = Vec.getValueType();
// If index isn't constant, assume we need all vector elements AND the
// inserted element.
APInt DemandedVecElts(DemandedElts);
if (CIdx && CIdx->getAPIntValue().ult(VecVT.getVectorNumElements())) {
unsigned Idx = CIdx->getZExtValue();
DemandedVecElts.clearBit(Idx);
// Inserted element is not required.
if (!DemandedElts[Idx])
return TLO.CombineTo(Op, Vec);
}
KnownBits KnownScl;
unsigned NumSclBits = Scl.getScalarValueSizeInBits();
APInt DemandedSclBits = DemandedBits.zextOrTrunc(NumSclBits);
if (SimplifyDemandedBits(Scl, DemandedSclBits, KnownScl, TLO, Depth + 1))
return true;
Known = KnownScl.anyextOrTrunc(BitWidth);
KnownBits KnownVec;
if (SimplifyDemandedBits(Vec, DemandedBits, DemandedVecElts, KnownVec, TLO,
Depth + 1))
return true;
if (!!DemandedVecElts) {
Known.One &= KnownVec.One;
Known.Zero &= KnownVec.Zero;
}
return false;
}
case ISD::INSERT_SUBVECTOR: {
// Demand any elements from the subvector and the remainder from the src its
// inserted into.
SDValue Src = Op.getOperand(0);
SDValue Sub = Op.getOperand(1);
uint64_t Idx = Op.getConstantOperandVal(2);
unsigned NumSubElts = Sub.getValueType().getVectorNumElements();
APInt DemandedSubElts = DemandedElts.extractBits(NumSubElts, Idx);
APInt DemandedSrcElts = DemandedElts;
DemandedSrcElts.insertBits(APInt::getNullValue(NumSubElts), Idx);
KnownBits KnownSub, KnownSrc;
if (SimplifyDemandedBits(Sub, DemandedBits, DemandedSubElts, KnownSub, TLO,
Depth + 1))
return true;
if (SimplifyDemandedBits(Src, DemandedBits, DemandedSrcElts, KnownSrc, TLO,
Depth + 1))
return true;
Known.Zero.setAllBits();
Known.One.setAllBits();
if (!!DemandedSubElts) {
Known.One &= KnownSub.One;
Known.Zero &= KnownSub.Zero;
}
if (!!DemandedSrcElts) {
Known.One &= KnownSrc.One;
Known.Zero &= KnownSrc.Zero;
}
// Attempt to avoid multi-use src if we don't need anything from it.
if (!DemandedBits.isAllOnesValue() || !DemandedSubElts.isAllOnesValue() ||
!DemandedSrcElts.isAllOnesValue()) {
SDValue NewSub = SimplifyMultipleUseDemandedBits(
Sub, DemandedBits, DemandedSubElts, TLO.DAG, Depth + 1);
SDValue NewSrc = SimplifyMultipleUseDemandedBits(
Src, DemandedBits, DemandedSrcElts, TLO.DAG, Depth + 1);
if (NewSub || NewSrc) {
NewSub = NewSub ? NewSub : Sub;
NewSrc = NewSrc ? NewSrc : Src;
SDValue NewOp = TLO.DAG.getNode(Op.getOpcode(), dl, VT, NewSrc, NewSub,
Op.getOperand(2));
return TLO.CombineTo(Op, NewOp);
}
}
break;
}
case ISD::EXTRACT_SUBVECTOR: {
// Offset the demanded elts by the subvector index.
SDValue Src = Op.getOperand(0);
if (Src.getValueType().isScalableVector())
break;
uint64_t Idx = Op.getConstantOperandVal(1);
unsigned NumSrcElts = Src.getValueType().getVectorNumElements();
APInt DemandedSrcElts = DemandedElts.zextOrSelf(NumSrcElts).shl(Idx);
if (SimplifyDemandedBits(Src, DemandedBits, DemandedSrcElts, Known, TLO,
Depth + 1))
return true;
// Attempt to avoid multi-use src if we don't need anything from it.
if (!DemandedBits.isAllOnesValue() || !DemandedSrcElts.isAllOnesValue()) {
SDValue DemandedSrc = SimplifyMultipleUseDemandedBits(
Src, DemandedBits, DemandedSrcElts, TLO.DAG, Depth + 1);
if (DemandedSrc) {
SDValue NewOp = TLO.DAG.getNode(Op.getOpcode(), dl, VT, DemandedSrc,
Op.getOperand(1));
return TLO.CombineTo(Op, NewOp);
}
}
break;
}
case ISD::CONCAT_VECTORS: {
Known.Zero.setAllBits();
Known.One.setAllBits();
EVT SubVT = Op.getOperand(0).getValueType();
unsigned NumSubVecs = Op.getNumOperands();
unsigned NumSubElts = SubVT.getVectorNumElements();
for (unsigned i = 0; i != NumSubVecs; ++i) {
APInt DemandedSubElts =
DemandedElts.extractBits(NumSubElts, i * NumSubElts);
if (SimplifyDemandedBits(Op.getOperand(i), DemandedBits, DemandedSubElts,
Known2, TLO, Depth + 1))
return true;
// Known bits are shared by every demanded subvector element.
if (!!DemandedSubElts) {
Known.One &= Known2.One;
Known.Zero &= Known2.Zero;
}
}
break;
}
case ISD::VECTOR_SHUFFLE: {
ArrayRef<int> ShuffleMask = cast<ShuffleVectorSDNode>(Op)->getMask();
// Collect demanded elements from shuffle operands..
APInt DemandedLHS(NumElts, 0);
APInt DemandedRHS(NumElts, 0);
for (unsigned i = 0; i != NumElts; ++i) {
if (!DemandedElts[i])
continue;
int M = ShuffleMask[i];
if (M < 0) {
// For UNDEF elements, we don't know anything about the common state of
// the shuffle result.
DemandedLHS.clearAllBits();
DemandedRHS.clearAllBits();
break;
}
assert(0 <= M && M < (int)(2 * NumElts) && "Shuffle index out of range");
if (M < (int)NumElts)
DemandedLHS.setBit(M);
else
DemandedRHS.setBit(M - NumElts);
}
if (!!DemandedLHS || !!DemandedRHS) {
SDValue Op0 = Op.getOperand(0);
SDValue Op1 = Op.getOperand(1);
Known.Zero.setAllBits();
Known.One.setAllBits();
if (!!DemandedLHS) {
if (SimplifyDemandedBits(Op0, DemandedBits, DemandedLHS, Known2, TLO,
Depth + 1))
return true;
Known.One &= Known2.One;
Known.Zero &= Known2.Zero;
}
if (!!DemandedRHS) {
if (SimplifyDemandedBits(Op1, DemandedBits, DemandedRHS, Known2, TLO,
Depth + 1))
return true;
Known.One &= Known2.One;
Known.Zero &= Known2.Zero;
}
// Attempt to avoid multi-use ops if we don't need anything from them.
SDValue DemandedOp0 = SimplifyMultipleUseDemandedBits(
Op0, DemandedBits, DemandedLHS, TLO.DAG, Depth + 1);
SDValue DemandedOp1 = SimplifyMultipleUseDemandedBits(
Op1, DemandedBits, DemandedRHS, TLO.DAG, Depth + 1);
if (DemandedOp0 || DemandedOp1) {
Op0 = DemandedOp0 ? DemandedOp0 : Op0;
Op1 = DemandedOp1 ? DemandedOp1 : Op1;
SDValue NewOp = TLO.DAG.getVectorShuffle(VT, dl, Op0, Op1, ShuffleMask);
return TLO.CombineTo(Op, NewOp);
}
}
break;
}
case ISD::AND: {
SDValue Op0 = Op.getOperand(0);
SDValue Op1 = Op.getOperand(1);
// If the RHS is a constant, check to see if the LHS would be zero without
// using the bits from the RHS. Below, we use knowledge about the RHS to
// simplify the LHS, here we're using information from the LHS to simplify
// the RHS.
if (ConstantSDNode *RHSC = isConstOrConstSplat(Op1)) {
// Do not increment Depth here; that can cause an infinite loop.
KnownBits LHSKnown = TLO.DAG.computeKnownBits(Op0, DemandedElts, Depth);
// If the LHS already has zeros where RHSC does, this 'and' is dead.
if ((LHSKnown.Zero & DemandedBits) ==
(~RHSC->getAPIntValue() & DemandedBits))
return TLO.CombineTo(Op, Op0);
// If any of the set bits in the RHS are known zero on the LHS, shrink
// the constant.
if (ShrinkDemandedConstant(Op, ~LHSKnown.Zero & DemandedBits,
DemandedElts, TLO))
return true;
// Bitwise-not (xor X, -1) is a special case: we don't usually shrink its
// constant, but if this 'and' is only clearing bits that were just set by
// the xor, then this 'and' can be eliminated by shrinking the mask of
// the xor. For example, for a 32-bit X:
// and (xor (srl X, 31), -1), 1 --> xor (srl X, 31), 1
if (isBitwiseNot(Op0) && Op0.hasOneUse() &&
LHSKnown.One == ~RHSC->getAPIntValue()) {
SDValue Xor = TLO.DAG.getNode(ISD::XOR, dl, VT, Op0.getOperand(0), Op1);
return TLO.CombineTo(Op, Xor);
}
}
if (SimplifyDemandedBits(Op1, DemandedBits, DemandedElts, Known, TLO,
Depth + 1))
return true;
assert(!Known.hasConflict() && "Bits known to be one AND zero?");
if (SimplifyDemandedBits(Op0, ~Known.Zero & DemandedBits, DemandedElts,
Known2, TLO, Depth + 1))
return true;
assert(!Known2.hasConflict() && "Bits known to be one AND zero?");
// Attempt to avoid multi-use ops if we don't need anything from them.
if (!DemandedBits.isAllOnesValue() || !DemandedElts.isAllOnesValue()) {
SDValue DemandedOp0 = SimplifyMultipleUseDemandedBits(
Op0, DemandedBits, DemandedElts, TLO.DAG, Depth + 1);
SDValue DemandedOp1 = SimplifyMultipleUseDemandedBits(
Op1, DemandedBits, DemandedElts, TLO.DAG, Depth + 1);
if (DemandedOp0 || DemandedOp1) {
Op0 = DemandedOp0 ? DemandedOp0 : Op0;
Op1 = DemandedOp1 ? DemandedOp1 : Op1;
SDValue NewOp = TLO.DAG.getNode(Op.getOpcode(), dl, VT, Op0, Op1);
return TLO.CombineTo(Op, NewOp);
}
}
// If all of the demanded bits are known one on one side, return the other.
// These bits cannot contribute to the result of the 'and'.
if (DemandedBits.isSubsetOf(Known2.Zero | Known.One))
return TLO.CombineTo(Op, Op0);
if (DemandedBits.isSubsetOf(Known.Zero | Known2.One))
return TLO.CombineTo(Op, Op1);
// If all of the demanded bits in the inputs are known zeros, return zero.
if (DemandedBits.isSubsetOf(Known.Zero | Known2.Zero))
return TLO.CombineTo(Op, TLO.DAG.getConstant(0, dl, VT));
// If the RHS is a constant, see if we can simplify it.
if (ShrinkDemandedConstant(Op, ~Known2.Zero & DemandedBits, DemandedElts,
TLO))
return true;
// If the operation can be done in a smaller type, do so.
if (ShrinkDemandedOp(Op, BitWidth, DemandedBits, TLO))
return true;
Known &= Known2;
break;
}
case ISD::OR: {
SDValue Op0 = Op.getOperand(0);
SDValue Op1 = Op.getOperand(1);
if (SimplifyDemandedBits(Op1, DemandedBits, DemandedElts, Known, TLO,
Depth + 1))
return true;
assert(!Known.hasConflict() && "Bits known to be one AND zero?");
if (SimplifyDemandedBits(Op0, ~Known.One & DemandedBits, DemandedElts,
Known2, TLO, Depth + 1))
return true;
assert(!Known2.hasConflict() && "Bits known to be one AND zero?");
// Attempt to avoid multi-use ops if we don't need anything from them.
if (!DemandedBits.isAllOnesValue() || !DemandedElts.isAllOnesValue()) {
SDValue DemandedOp0 = SimplifyMultipleUseDemandedBits(
Op0, DemandedBits, DemandedElts, TLO.DAG, Depth + 1);
SDValue DemandedOp1 = SimplifyMultipleUseDemandedBits(
Op1, DemandedBits, DemandedElts, TLO.DAG, Depth + 1);
if (DemandedOp0 || DemandedOp1) {
Op0 = DemandedOp0 ? DemandedOp0 : Op0;
Op1 = DemandedOp1 ? DemandedOp1 : Op1;
SDValue NewOp = TLO.DAG.getNode(Op.getOpcode(), dl, VT, Op0, Op1);
return TLO.CombineTo(Op, NewOp);
}
}
// If all of the demanded bits are known zero on one side, return the other.
// These bits cannot contribute to the result of the 'or'.
if (DemandedBits.isSubsetOf(Known2.One | Known.Zero))
return TLO.CombineTo(Op, Op0);
if (DemandedBits.isSubsetOf(Known.One | Known2.Zero))
return TLO.CombineTo(Op, Op1);
// If the RHS is a constant, see if we can simplify it.
if (ShrinkDemandedConstant(Op, DemandedBits, DemandedElts, TLO))
return true;
// If the operation can be done in a smaller type, do so.
if (ShrinkDemandedOp(Op, BitWidth, DemandedBits, TLO))
return true;
Known |= Known2;
break;
}
case ISD::XOR: {
SDValue Op0 = Op.getOperand(0);
SDValue Op1 = Op.getOperand(1);
if (SimplifyDemandedBits(Op1, DemandedBits, DemandedElts, Known, TLO,
Depth + 1))
return true;
assert(!Known.hasConflict() && "Bits known to be one AND zero?");
if (SimplifyDemandedBits(Op0, DemandedBits, DemandedElts, Known2, TLO,
Depth + 1))
return true;
assert(!Known2.hasConflict() && "Bits known to be one AND zero?");
// Attempt to avoid multi-use ops if we don't need anything from them.
if (!DemandedBits.isAllOnesValue() || !DemandedElts.isAllOnesValue()) {
SDValue DemandedOp0 = SimplifyMultipleUseDemandedBits(
Op0, DemandedBits, DemandedElts, TLO.DAG, Depth + 1);
SDValue DemandedOp1 = SimplifyMultipleUseDemandedBits(
Op1, DemandedBits, DemandedElts, TLO.DAG, Depth + 1);
if (DemandedOp0 || DemandedOp1) {
Op0 = DemandedOp0 ? DemandedOp0 : Op0;
Op1 = DemandedOp1 ? DemandedOp1 : Op1;
SDValue NewOp = TLO.DAG.getNode(Op.getOpcode(), dl, VT, Op0, Op1);
return TLO.CombineTo(Op, NewOp);
}
}
// If all of the demanded bits are known zero on one side, return the other.
// These bits cannot contribute to the result of the 'xor'.
if (DemandedBits.isSubsetOf(Known.Zero))
return TLO.CombineTo(Op, Op0);
if (DemandedBits.isSubsetOf(Known2.Zero))
return TLO.CombineTo(Op, Op1);
// If the operation can be done in a smaller type, do so.
if (ShrinkDemandedOp(Op, BitWidth, DemandedBits, TLO))
return true;
// If all of the unknown bits are known to be zero on one side or the other
// (but not both) turn this into an *inclusive* or.
// e.g. (A & C1)^(B & C2) -> (A & C1)|(B & C2) iff C1&C2 == 0
if (DemandedBits.isSubsetOf(Known.Zero | Known2.Zero))
return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::OR, dl, VT, Op0, Op1));
ConstantSDNode* C = isConstOrConstSplat(Op1, DemandedElts);
if (C) {
// If one side is a constant, and all of the known set bits on the other
// side are also set in the constant, turn this into an AND, as we know
// the bits will be cleared.
// e.g. (X | C1) ^ C2 --> (X | C1) & ~C2 iff (C1&C2) == C2
// NB: it is okay if more bits are known than are requested
if (C->getAPIntValue() == Known2.One) {
SDValue ANDC =
TLO.DAG.getConstant(~C->getAPIntValue() & DemandedBits, dl, VT);
return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::AND, dl, VT, Op0, ANDC));
}
// If the RHS is a constant, see if we can change it. Don't alter a -1
// constant because that's a 'not' op, and that is better for combining
// and codegen.
if (!C->isAllOnesValue() &&
DemandedBits.isSubsetOf(C->getAPIntValue())) {
// We're flipping all demanded bits. Flip the undemanded bits too.
SDValue New = TLO.DAG.getNOT(dl, Op0, VT);
return TLO.CombineTo(Op, New);
}
}
// If we can't turn this into a 'not', try to shrink the constant.
if (!C || !C->isAllOnesValue())
if (ShrinkDemandedConstant(Op, DemandedBits, DemandedElts, TLO))
return true;
Known ^= Known2;
break;
}
case ISD::SELECT:
if (SimplifyDemandedBits(Op.getOperand(2), DemandedBits, Known, TLO,
Depth + 1))
return true;
if (SimplifyDemandedBits(Op.getOperand(1), DemandedBits, Known2, TLO,
Depth + 1))
return true;
assert(!Known.hasConflict() && "Bits known to be one AND zero?");
assert(!Known2.hasConflict() && "Bits known to be one AND zero?");
// If the operands are constants, see if we can simplify them.
if (ShrinkDemandedConstant(Op, DemandedBits, DemandedElts, TLO))
return true;
// Only known if known in both the LHS and RHS.
Known.One &= Known2.One;
Known.Zero &= Known2.Zero;
break;
case ISD::SELECT_CC:
if (SimplifyDemandedBits(Op.getOperand(3), DemandedBits, Known, TLO,
Depth + 1))
return true;
if (SimplifyDemandedBits(Op.getOperand(2), DemandedBits, Known2, TLO,
Depth + 1))
return true;
assert(!Known.hasConflict() && "Bits known to be one AND zero?");
assert(!Known2.hasConflict() && "Bits known to be one AND zero?");
// If the operands are constants, see if we can simplify them.
if (ShrinkDemandedConstant(Op, DemandedBits, DemandedElts, TLO))
return true;
// Only known if known in both the LHS and RHS.
Known.One &= Known2.One;
Known.Zero &= Known2.Zero;
break;
case ISD::SETCC: {
SDValue Op0 = Op.getOperand(0);
SDValue Op1 = Op.getOperand(1);
ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(2))->get();
// If (1) we only need the sign-bit, (2) the setcc operands are the same
// width as the setcc result, and (3) the result of a setcc conforms to 0 or
// -1, we may be able to bypass the setcc.
if (DemandedBits.isSignMask() &&
Op0.getScalarValueSizeInBits() == BitWidth &&
getBooleanContents(Op0.getValueType()) ==
BooleanContent::ZeroOrNegativeOneBooleanContent) {
// If we're testing X < 0, then this compare isn't needed - just use X!
// FIXME: We're limiting to integer types here, but this should also work
// if we don't care about FP signed-zero. The use of SETLT with FP means
// that we don't care about NaNs.
if (CC == ISD::SETLT && Op1.getValueType().isInteger() &&
(isNullConstant(Op1) || ISD::isBuildVectorAllZeros(Op1.getNode())))
return TLO.CombineTo(Op, Op0);
// TODO: Should we check for other forms of sign-bit comparisons?
// Examples: X <= -1, X >= 0
}
if (getBooleanContents(Op0.getValueType()) ==
TargetLowering::ZeroOrOneBooleanContent &&
BitWidth > 1)
Known.Zero.setBitsFrom(1);
break;
}
case ISD::SHL: {
SDValue Op0 = Op.getOperand(0);
SDValue Op1 = Op.getOperand(1);
EVT ShiftVT = Op1.getValueType();
if (const APInt *SA =
TLO.DAG.getValidShiftAmountConstant(Op, DemandedElts)) {
unsigned ShAmt = SA->getZExtValue();
if (ShAmt == 0)
return TLO.CombineTo(Op, Op0);
// If this is ((X >>u C1) << ShAmt), see if we can simplify this into a
// single shift. We can do this if the bottom bits (which are shifted
// out) are never demanded.
// TODO - support non-uniform vector amounts.
if (Op0.getOpcode() == ISD::SRL) {
if (!DemandedBits.intersects(APInt::getLowBitsSet(BitWidth, ShAmt))) {
if (const APInt *SA2 =
TLO.DAG.getValidShiftAmountConstant(Op0, DemandedElts)) {
unsigned C1 = SA2->getZExtValue();
unsigned Opc = ISD::SHL;
int Diff = ShAmt - C1;
if (Diff < 0) {
Diff = -Diff;
Opc = ISD::SRL;
}
SDValue NewSA = TLO.DAG.getConstant(Diff, dl, ShiftVT);
return TLO.CombineTo(
Op, TLO.DAG.getNode(Opc, dl, VT, Op0.getOperand(0), NewSA));
}
}
}
// Convert (shl (anyext x, c)) to (anyext (shl x, c)) if the high bits
// are not demanded. This will likely allow the anyext to be folded away.
// TODO - support non-uniform vector amounts.
if (Op0.getOpcode() == ISD::ANY_EXTEND) {
SDValue InnerOp = Op0.getOperand(0);
EVT InnerVT = InnerOp.getValueType();
unsigned InnerBits = InnerVT.getScalarSizeInBits();
if (ShAmt < InnerBits && DemandedBits.getActiveBits() <= InnerBits &&
isTypeDesirableForOp(ISD::SHL, InnerVT)) {
EVT ShTy = getShiftAmountTy(InnerVT, DL);
if (!APInt(BitWidth, ShAmt).isIntN(ShTy.getSizeInBits()))
ShTy = InnerVT;
SDValue NarrowShl =
TLO.DAG.getNode(ISD::SHL, dl, InnerVT, InnerOp,
TLO.DAG.getConstant(ShAmt, dl, ShTy));
return TLO.CombineTo(
Op, TLO.DAG.getNode(ISD::ANY_EXTEND, dl, VT, NarrowShl));
}
// Repeat the SHL optimization above in cases where an extension
// intervenes: (shl (anyext (shr x, c1)), c2) to
// (shl (anyext x), c2-c1). This requires that the bottom c1 bits
// aren't demanded (as above) and that the shifted upper c1 bits of
// x aren't demanded.
// TODO - support non-uniform vector amounts.
if (Op0.hasOneUse() && InnerOp.getOpcode() == ISD::SRL &&
InnerOp.hasOneUse()) {
if (const APInt *SA2 =
TLO.DAG.getValidShiftAmountConstant(InnerOp, DemandedElts)) {
unsigned InnerShAmt = SA2->getZExtValue();
if (InnerShAmt < ShAmt && InnerShAmt < InnerBits &&
DemandedBits.getActiveBits() <=
(InnerBits - InnerShAmt + ShAmt) &&
DemandedBits.countTrailingZeros() >= ShAmt) {
SDValue NewSA =
TLO.DAG.getConstant(ShAmt - InnerShAmt, dl, ShiftVT);
SDValue NewExt = TLO.DAG.getNode(ISD::ANY_EXTEND, dl, VT,
InnerOp.getOperand(0));
return TLO.CombineTo(
Op, TLO.DAG.getNode(ISD::SHL, dl, VT, NewExt, NewSA));
}
}
}
}
APInt InDemandedMask = DemandedBits.lshr(ShAmt);
if (SimplifyDemandedBits(Op0, InDemandedMask, DemandedElts, Known, TLO,
Depth + 1))
return true;
assert(!Known.hasConflict() && "Bits known to be one AND zero?");
Known.Zero <<= ShAmt;
Known.One <<= ShAmt;
// low bits known zero.
Known.Zero.setLowBits(ShAmt);
// Try shrinking the operation as long as the shift amount will still be
// in range.
if ((ShAmt < DemandedBits.getActiveBits()) &&
ShrinkDemandedOp(Op, BitWidth, DemandedBits, TLO))
return true;
}
// If we are only demanding sign bits then we can use the shift source
// directly.
if (const APInt *MaxSA =
TLO.DAG.getValidMaximumShiftAmountConstant(Op, DemandedElts)) {
unsigned ShAmt = MaxSA->getZExtValue();
unsigned NumSignBits =
TLO.DAG.ComputeNumSignBits(Op0, DemandedElts, Depth + 1);
unsigned UpperDemandedBits = BitWidth - DemandedBits.countTrailingZeros();
if (NumSignBits > ShAmt && (NumSignBits - ShAmt) >= (UpperDemandedBits))
return TLO.CombineTo(Op, Op0);
}
break;
}
case ISD::SRL: {
SDValue Op0 = Op.getOperand(0);
SDValue Op1 = Op.getOperand(1);
EVT ShiftVT = Op1.getValueType();
if (const APInt *SA =
TLO.DAG.getValidShiftAmountConstant(Op, DemandedElts)) {
unsigned ShAmt = SA->getZExtValue();
if (ShAmt == 0)
return TLO.CombineTo(Op, Op0);
// If this is ((X << C1) >>u ShAmt), see if we can simplify this into a
// single shift. We can do this if the top bits (which are shifted out)
// are never demanded.
// TODO - support non-uniform vector amounts.
if (Op0.getOpcode() == ISD::SHL) {
if (!DemandedBits.intersects(APInt::getHighBitsSet(BitWidth, ShAmt))) {
if (const APInt *SA2 =
TLO.DAG.getValidShiftAmountConstant(Op0, DemandedElts)) {
unsigned C1 = SA2->getZExtValue();
unsigned Opc = ISD::SRL;
int Diff = ShAmt - C1;
if (Diff < 0) {
Diff = -Diff;
Opc = ISD::SHL;
}
SDValue NewSA = TLO.DAG.getConstant(Diff, dl, ShiftVT);
return TLO.CombineTo(
Op, TLO.DAG.getNode(Opc, dl, VT, Op0.getOperand(0), NewSA));
}
}
}
APInt InDemandedMask = (DemandedBits << ShAmt);
// If the shift is exact, then it does demand the low bits (and knows that
// they are zero).
if (Op->getFlags().hasExact())
InDemandedMask.setLowBits(ShAmt);
// Compute the new bits that are at the top now.
if (SimplifyDemandedBits(Op0, InDemandedMask, DemandedElts, Known, TLO,
Depth + 1))
return true;
assert(!Known.hasConflict() && "Bits known to be one AND zero?");
Known.Zero.lshrInPlace(ShAmt);
Known.One.lshrInPlace(ShAmt);
// High bits known zero.
Known.Zero.setHighBits(ShAmt);
}
break;
}
case ISD::SRA: {
SDValue Op0 = Op.getOperand(0);
SDValue Op1 = Op.getOperand(1);
EVT ShiftVT = Op1.getValueType();
// If we only want bits that already match the signbit then we don't need
// to shift.
unsigned NumHiDemandedBits = BitWidth - DemandedBits.countTrailingZeros();
if (TLO.DAG.ComputeNumSignBits(Op0, DemandedElts, Depth + 1) >=
NumHiDemandedBits)
return TLO.CombineTo(Op, Op0);
// If this is an arithmetic shift right and only the low-bit is set, we can
// always convert this into a logical shr, even if the shift amount is
// variable. The low bit of the shift cannot be an input sign bit unless
// the shift amount is >= the size of the datatype, which is undefined.
if (DemandedBits.isOneValue())
return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::SRL, dl, VT, Op0, Op1));
if (const APInt *SA =
TLO.DAG.getValidShiftAmountConstant(Op, DemandedElts)) {
unsigned ShAmt = SA->getZExtValue();
if (ShAmt == 0)
return TLO.CombineTo(Op, Op0);
APInt InDemandedMask = (DemandedBits << ShAmt);
// If the shift is exact, then it does demand the low bits (and knows that
// they are zero).
if (Op->getFlags().hasExact())
InDemandedMask.setLowBits(ShAmt);
// If any of the demanded bits are produced by the sign extension, we also
// demand the input sign bit.
if (DemandedBits.countLeadingZeros() < ShAmt)
InDemandedMask.setSignBit();
if (SimplifyDemandedBits(Op0, InDemandedMask, DemandedElts, Known, TLO,
Depth + 1))
return true;
assert(!Known.hasConflict() && "Bits known to be one AND zero?");
Known.Zero.lshrInPlace(ShAmt);
Known.One.lshrInPlace(ShAmt);
// If the input sign bit is known to be zero, or if none of the top bits
// are demanded, turn this into an unsigned shift right.
if (Known.Zero[BitWidth - ShAmt - 1] ||
DemandedBits.countLeadingZeros() >= ShAmt) {
SDNodeFlags Flags;
Flags.setExact(Op->getFlags().hasExact());
return TLO.CombineTo(
Op, TLO.DAG.getNode(ISD::SRL, dl, VT, Op0, Op1, Flags));
}
int Log2 = DemandedBits.exactLogBase2();
if (Log2 >= 0) {
// The bit must come from the sign.
SDValue NewSA = TLO.DAG.getConstant(BitWidth - 1 - Log2, dl, ShiftVT);
return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::SRL, dl, VT, Op0, NewSA));
}
if (Known.One[BitWidth - ShAmt - 1])
// New bits are known one.
Known.One.setHighBits(ShAmt);
// Attempt to avoid multi-use ops if we don't need anything from them.
if (!InDemandedMask.isAllOnesValue() || !DemandedElts.isAllOnesValue()) {
SDValue DemandedOp0 = SimplifyMultipleUseDemandedBits(
Op0, InDemandedMask, DemandedElts, TLO.DAG, Depth + 1);
if (DemandedOp0) {
SDValue NewOp = TLO.DAG.getNode(ISD::SRA, dl, VT, DemandedOp0, Op1);
return TLO.CombineTo(Op, NewOp);
}
}
}
break;
}
case ISD::FSHL:
case ISD::FSHR: {
SDValue Op0 = Op.getOperand(0);
SDValue Op1 = Op.getOperand(1);
SDValue Op2 = Op.getOperand(2);
bool IsFSHL = (Op.getOpcode() == ISD::FSHL);
if (ConstantSDNode *SA = isConstOrConstSplat(Op2, DemandedElts)) {
unsigned Amt = SA->getAPIntValue().urem(BitWidth);
// For fshl, 0-shift returns the 1st arg.
// For fshr, 0-shift returns the 2nd arg.
if (Amt == 0) {
if (SimplifyDemandedBits(IsFSHL ? Op0 : Op1, DemandedBits, DemandedElts,
Known, TLO, Depth + 1))
return true;
break;
}
// fshl: (Op0 << Amt) | (Op1 >> (BW - Amt))
// fshr: (Op0 << (BW - Amt)) | (Op1 >> Amt)
APInt Demanded0 = DemandedBits.lshr(IsFSHL ? Amt : (BitWidth - Amt));
APInt Demanded1 = DemandedBits << (IsFSHL ? (BitWidth - Amt) : Amt);
if (SimplifyDemandedBits(Op0, Demanded0, DemandedElts, Known2, TLO,
Depth + 1))
return true;
if (SimplifyDemandedBits(Op1, Demanded1, DemandedElts, Known, TLO,
Depth + 1))
return true;
Known2.One <<= (IsFSHL ? Amt : (BitWidth - Amt));
Known2.Zero <<= (IsFSHL ? Amt : (BitWidth - Amt));
Known.One.lshrInPlace(IsFSHL ? (BitWidth - Amt) : Amt);
Known.Zero.lshrInPlace(IsFSHL ? (BitWidth - Amt) : Amt);
Known.One |= Known2.One;
Known.Zero |= Known2.Zero;
}
// For pow-2 bitwidths we only demand the bottom modulo amt bits.
if (isPowerOf2_32(BitWidth)) {
APInt DemandedAmtBits(Op2.getScalarValueSizeInBits(), BitWidth - 1);
if (SimplifyDemandedBits(Op2, DemandedAmtBits, DemandedElts,
Known2, TLO, Depth + 1))
return true;
}
break;
}
case ISD::ROTL:
case ISD::ROTR: {
SDValue Op0 = Op.getOperand(0);
SDValue Op1 = Op.getOperand(1);
// If we're rotating an 0/-1 value, then it stays an 0/-1 value.
if (BitWidth == TLO.DAG.ComputeNumSignBits(Op0, DemandedElts, Depth + 1))
return TLO.CombineTo(Op, Op0);
// For pow-2 bitwidths we only demand the bottom modulo amt bits.
if (isPowerOf2_32(BitWidth)) {
APInt DemandedAmtBits(Op1.getScalarValueSizeInBits(), BitWidth - 1);
if (SimplifyDemandedBits(Op1, DemandedAmtBits, DemandedElts, Known2, TLO,
Depth + 1))
return true;
}
break;
}
case ISD::BITREVERSE: {
SDValue Src = Op.getOperand(0);
APInt DemandedSrcBits = DemandedBits.reverseBits();
if (SimplifyDemandedBits(Src, DemandedSrcBits, DemandedElts, Known2, TLO,
Depth + 1))
return true;
Known.One = Known2.One.reverseBits();
Known.Zero = Known2.Zero.reverseBits();
break;
}
case ISD::BSWAP: {
SDValue Src = Op.getOperand(0);
APInt DemandedSrcBits = DemandedBits.byteSwap();
if (SimplifyDemandedBits(Src, DemandedSrcBits, DemandedElts, Known2, TLO,
Depth + 1))
return true;
Known.One = Known2.One.byteSwap();
Known.Zero = Known2.Zero.byteSwap();
break;
}
case ISD::SIGN_EXTEND_INREG: {
SDValue Op0 = Op.getOperand(0);
EVT ExVT = cast<VTSDNode>(Op.getOperand(1))->getVT();
unsigned ExVTBits = ExVT.getScalarSizeInBits();
// If we only care about the highest bit, don't bother shifting right.
if (DemandedBits.isSignMask()) {
unsigned NumSignBits =
TLO.DAG.ComputeNumSignBits(Op0, DemandedElts, Depth + 1);
bool AlreadySignExtended = NumSignBits >= BitWidth - ExVTBits + 1;
// However if the input is already sign extended we expect the sign
// extension to be dropped altogether later and do not simplify.
if (!AlreadySignExtended) {
// Compute the correct shift amount type, which must be getShiftAmountTy
// for scalar types after legalization.
EVT ShiftAmtTy = VT;
if (TLO.LegalTypes() && !ShiftAmtTy.isVector())
ShiftAmtTy = getShiftAmountTy(ShiftAmtTy, DL);
SDValue ShiftAmt =
TLO.DAG.getConstant(BitWidth - ExVTBits, dl, ShiftAmtTy);
return TLO.CombineTo(Op,
TLO.DAG.getNode(ISD::SHL, dl, VT, Op0, ShiftAmt));
}
}
// If none of the extended bits are demanded, eliminate the sextinreg.
if (DemandedBits.getActiveBits() <= ExVTBits)
return TLO.CombineTo(Op, Op0);
APInt InputDemandedBits = DemandedBits.getLoBits(ExVTBits);
// Since the sign extended bits are demanded, we know that the sign
// bit is demanded.
InputDemandedBits.setBit(ExVTBits - 1);
if (SimplifyDemandedBits(Op0, InputDemandedBits, Known, TLO, Depth + 1))
return true;
assert(!Known.hasConflict() && "Bits known to be one AND zero?");
// If the sign bit of the input is known set or clear, then we know the
// top bits of the result.
// If the input sign bit is known zero, convert this into a zero extension.
if (Known.Zero[ExVTBits - 1])
return TLO.CombineTo(Op, TLO.DAG.getZeroExtendInReg(Op0, dl, ExVT));
APInt Mask = APInt::getLowBitsSet(BitWidth, ExVTBits);
if (Known.One[ExVTBits - 1]) { // Input sign bit known set
Known.One.setBitsFrom(ExVTBits);
Known.Zero &= Mask;
} else { // Input sign bit unknown
Known.Zero &= Mask;
Known.One &= Mask;
}
break;
}
case ISD::BUILD_PAIR: {
EVT HalfVT = Op.getOperand(0).getValueType();
unsigned HalfBitWidth = HalfVT.getScalarSizeInBits();
APInt MaskLo = DemandedBits.getLoBits(HalfBitWidth).trunc(HalfBitWidth);
APInt MaskHi = DemandedBits.getHiBits(HalfBitWidth).trunc(HalfBitWidth);
KnownBits KnownLo, KnownHi;
if (SimplifyDemandedBits(Op.getOperand(0), MaskLo, KnownLo, TLO, Depth + 1))
return true;
if (SimplifyDemandedBits(Op.getOperand(1), MaskHi, KnownHi, TLO, Depth + 1))
return true;
Known.Zero = KnownLo.Zero.zext(BitWidth) |
KnownHi.Zero.zext(BitWidth).shl(HalfBitWidth);
Known.One = KnownLo.One.zext(BitWidth) |
KnownHi.One.zext(BitWidth).shl(HalfBitWidth);
break;
}
case ISD::ZERO_EXTEND:
case ISD::ZERO_EXTEND_VECTOR_INREG: {
SDValue Src = Op.getOperand(0);
EVT SrcVT = Src.getValueType();
unsigned InBits = SrcVT.getScalarSizeInBits();
unsigned InElts = SrcVT.isVector() ? SrcVT.getVectorNumElements() : 1;
bool IsVecInReg = Op.getOpcode() == ISD::ZERO_EXTEND_VECTOR_INREG;
// If none of the top bits are demanded, convert this into an any_extend.
if (DemandedBits.getActiveBits() <= InBits) {
// If we only need the non-extended bits of the bottom element
// then we can just bitcast to the result.
if (IsVecInReg && DemandedElts == 1 &&
VT.getSizeInBits() == SrcVT.getSizeInBits() &&
TLO.DAG.getDataLayout().isLittleEndian())
return TLO.CombineTo(Op, TLO.DAG.getBitcast(VT, Src));
unsigned Opc =
IsVecInReg ? ISD::ANY_EXTEND_VECTOR_INREG : ISD::ANY_EXTEND;
if (!TLO.LegalOperations() || isOperationLegal(Opc, VT))
return TLO.CombineTo(Op, TLO.DAG.getNode(Opc, dl, VT, Src));
}
APInt InDemandedBits = DemandedBits.trunc(InBits);
APInt InDemandedElts = DemandedElts.zextOrSelf(InElts);
if (SimplifyDemandedBits(Src, InDemandedBits, InDemandedElts, Known, TLO,
Depth + 1))
return true;
assert(!Known.hasConflict() && "Bits known to be one AND zero?");
assert(Known.getBitWidth() == InBits && "Src width has changed?");
Known = Known.zext(BitWidth);
break;
}
case ISD::SIGN_EXTEND:
case ISD::SIGN_EXTEND_VECTOR_INREG: {
SDValue Src = Op.getOperand(0);
EVT SrcVT = Src.getValueType();
unsigned InBits = SrcVT.getScalarSizeInBits();
unsigned InElts = SrcVT.isVector() ? SrcVT.getVectorNumElements() : 1;
bool IsVecInReg = Op.getOpcode() == ISD::SIGN_EXTEND_VECTOR_INREG;
// If none of the top bits are demanded, convert this into an any_extend.
if (DemandedBits.getActiveBits() <= InBits) {
// If we only need the non-extended bits of the bottom element
// then we can just bitcast to the result.
if (IsVecInReg && DemandedElts == 1 &&
VT.getSizeInBits() == SrcVT.getSizeInBits() &&
TLO.DAG.getDataLayout().isLittleEndian())
return TLO.CombineTo(Op, TLO.DAG.getBitcast(VT, Src));
unsigned Opc =
IsVecInReg ? ISD::ANY_EXTEND_VECTOR_INREG : ISD::ANY_EXTEND;
if (!TLO.LegalOperations() || isOperationLegal(Opc, VT))
return TLO.CombineTo(Op, TLO.DAG.getNode(Opc, dl, VT, Src));
}
APInt InDemandedBits = DemandedBits.trunc(InBits);
APInt InDemandedElts = DemandedElts.zextOrSelf(InElts);
// Since some of the sign extended bits are demanded, we know that the sign
// bit is demanded.
InDemandedBits.setBit(InBits - 1);
if (SimplifyDemandedBits(Src, InDemandedBits, InDemandedElts, Known, TLO,
Depth + 1))
return true;
assert(!Known.hasConflict() && "Bits known to be one AND zero?");
assert(Known.getBitWidth() == InBits && "Src width has changed?");
// If the sign bit is known one, the top bits match.
Known = Known.sext(BitWidth);
// If the sign bit is known zero, convert this to a zero extend.
if (Known.isNonNegative()) {
unsigned Opc =
IsVecInReg ? ISD::ZERO_EXTEND_VECTOR_INREG : ISD::ZERO_EXTEND;
if (!TLO.LegalOperations() || isOperationLegal(Opc, VT))
return TLO.CombineTo(Op, TLO.DAG.getNode(Opc, dl, VT, Src));
}
break;
}
case ISD::ANY_EXTEND:
case ISD::ANY_EXTEND_VECTOR_INREG: {
SDValue Src = Op.getOperand(0);
EVT SrcVT = Src.getValueType();
unsigned InBits = SrcVT.getScalarSizeInBits();
unsigned InElts = SrcVT.isVector() ? SrcVT.getVectorNumElements() : 1;
bool IsVecInReg = Op.getOpcode() == ISD::ANY_EXTEND_VECTOR_INREG;
// If we only need the bottom element then we can just bitcast.
// TODO: Handle ANY_EXTEND?
if (IsVecInReg && DemandedElts == 1 &&
VT.getSizeInBits() == SrcVT.getSizeInBits() &&
TLO.DAG.getDataLayout().isLittleEndian())
return TLO.CombineTo(Op, TLO.DAG.getBitcast(VT, Src));
APInt InDemandedBits = DemandedBits.trunc(InBits);
APInt InDemandedElts = DemandedElts.zextOrSelf(InElts);
if (SimplifyDemandedBits(Src, InDemandedBits, InDemandedElts, Known, TLO,
Depth + 1))
return true;
assert(!Known.hasConflict() && "Bits known to be one AND zero?");
assert(Known.getBitWidth() == InBits && "Src width has changed?");
Known = Known.anyext(BitWidth);
// Attempt to avoid multi-use ops if we don't need anything from them.
if (SDValue NewSrc = SimplifyMultipleUseDemandedBits(
Src, InDemandedBits, InDemandedElts, TLO.DAG, Depth + 1))
return TLO.CombineTo(Op, TLO.DAG.getNode(Op.getOpcode(), dl, VT, NewSrc));
break;
}
case ISD::TRUNCATE: {
SDValue Src = Op.getOperand(0);
// Simplify the input, using demanded bit information, and compute the known
// zero/one bits live out.
unsigned OperandBitWidth = Src.getScalarValueSizeInBits();
APInt TruncMask = DemandedBits.zext(OperandBitWidth);
if (SimplifyDemandedBits(Src, TruncMask, Known, TLO, Depth + 1))
return true;
Known = Known.trunc(BitWidth);
// Attempt to avoid multi-use ops if we don't need anything from them.
if (SDValue NewSrc = SimplifyMultipleUseDemandedBits(
Src, TruncMask, DemandedElts, TLO.DAG, Depth + 1))
return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::TRUNCATE, dl, VT, NewSrc));
// If the input is only used by this truncate, see if we can shrink it based
// on the known demanded bits.
if (Src.getNode()->hasOneUse()) {
switch (Src.getOpcode()) {
default:
break;
case ISD::SRL:
// Shrink SRL by a constant if none of the high bits shifted in are
// demanded.
if (TLO.LegalTypes() && !isTypeDesirableForOp(ISD::SRL, VT))
// Do not turn (vt1 truncate (vt2 srl)) into (vt1 srl) if vt1 is
// undesirable.
break;
SDValue ShAmt = Src.getOperand(1);
auto *ShAmtC = dyn_cast<ConstantSDNode>(ShAmt);
if (!ShAmtC || ShAmtC->getAPIntValue().uge(BitWidth))
break;
uint64_t ShVal = ShAmtC->getZExtValue();
APInt HighBits =
APInt::getHighBitsSet(OperandBitWidth, OperandBitWidth - BitWidth);
HighBits.lshrInPlace(ShVal);
HighBits = HighBits.trunc(BitWidth);
if (!(HighBits & DemandedBits)) {
// None of the shifted in bits are needed. Add a truncate of the
// shift input, then shift it.
if (TLO.LegalTypes())
ShAmt = TLO.DAG.getConstant(ShVal, dl, getShiftAmountTy(VT, DL));
SDValue NewTrunc =
TLO.DAG.getNode(ISD::TRUNCATE, dl, VT, Src.getOperand(0));
return TLO.CombineTo(
Op, TLO.DAG.getNode(ISD::SRL, dl, VT, NewTrunc, ShAmt));
}
break;
}
}
assert(!Known.hasConflict() && "Bits known to be one AND zero?");
break;
}
case ISD::AssertZext: {
// AssertZext demands all of the high bits, plus any of the low bits
// demanded by its users.
EVT ZVT = cast<VTSDNode>(Op.getOperand(1))->getVT();
APInt InMask = APInt::getLowBitsSet(BitWidth, ZVT.getSizeInBits());
if (SimplifyDemandedBits(Op.getOperand(0), ~InMask | DemandedBits, Known,
TLO, Depth + 1))
return true;
assert(!Known.hasConflict() && "Bits known to be one AND zero?");
Known.Zero |= ~InMask;
break;
}
case ISD::EXTRACT_VECTOR_ELT: {
SDValue Src = Op.getOperand(0);
SDValue Idx = Op.getOperand(1);
unsigned NumSrcElts = Src.getValueType().getVectorNumElements();
unsigned EltBitWidth = Src.getScalarValueSizeInBits();
// Demand the bits from every vector element without a constant index.
APInt DemandedSrcElts = APInt::getAllOnesValue(NumSrcElts);
if (auto *CIdx = dyn_cast<ConstantSDNode>(Idx))
if (CIdx->getAPIntValue().ult(NumSrcElts))
DemandedSrcElts = APInt::getOneBitSet(NumSrcElts, CIdx->getZExtValue());
// If BitWidth > EltBitWidth the value is anyext:ed. So we do not know
// anything about the extended bits.
APInt DemandedSrcBits = DemandedBits;
if (BitWidth > EltBitWidth)
DemandedSrcBits = DemandedSrcBits.trunc(EltBitWidth);
if (SimplifyDemandedBits(Src, DemandedSrcBits, DemandedSrcElts, Known2, TLO,
Depth + 1))
return true;
// Attempt to avoid multi-use ops if we don't need anything from them.
if (!DemandedSrcBits.isAllOnesValue() ||
!DemandedSrcElts.isAllOnesValue()) {
if (SDValue DemandedSrc = SimplifyMultipleUseDemandedBits(
Src, DemandedSrcBits, DemandedSrcElts, TLO.DAG, Depth + 1)) {
SDValue NewOp =
TLO.DAG.getNode(Op.getOpcode(), dl, VT, DemandedSrc, Idx);
return TLO.CombineTo(Op, NewOp);
}
}
Known = Known2;
if (BitWidth > EltBitWidth)
Known = Known.anyext(BitWidth);
break;
}
case ISD::BITCAST: {
SDValue Src = Op.getOperand(0);
EVT SrcVT = Src.getValueType();
unsigned NumSrcEltBits = SrcVT.getScalarSizeInBits();
// If this is an FP->Int bitcast and if the sign bit is the only
// thing demanded, turn this into a FGETSIGN.
if (!TLO.LegalOperations() && !VT.isVector() && !SrcVT.isVector() &&
DemandedBits == APInt::getSignMask(Op.getValueSizeInBits()) &&
SrcVT.isFloatingPoint()) {
bool OpVTLegal = isOperationLegalOrCustom(ISD::FGETSIGN, VT);
bool i32Legal = isOperationLegalOrCustom(ISD::FGETSIGN, MVT::i32);
if ((OpVTLegal || i32Legal) && VT.isSimple() && SrcVT != MVT::f16 &&
SrcVT != MVT::f128) {
// Cannot eliminate/lower SHL for f128 yet.
EVT Ty = OpVTLegal ? VT : MVT::i32;
// Make a FGETSIGN + SHL to move the sign bit into the appropriate
// place. We expect the SHL to be eliminated by other optimizations.
SDValue Sign = TLO.DAG.getNode(ISD::FGETSIGN, dl, Ty, Src);
unsigned OpVTSizeInBits = Op.getValueSizeInBits();
if (!OpVTLegal && OpVTSizeInBits > 32)
Sign = TLO.DAG.getNode(ISD::ZERO_EXTEND, dl, VT, Sign);
unsigned ShVal = Op.getValueSizeInBits() - 1;
SDValue ShAmt = TLO.DAG.getConstant(ShVal, dl, VT);
return TLO.CombineTo(Op,
TLO.DAG.getNode(ISD::SHL, dl, VT, Sign, ShAmt));
}
}
// Bitcast from a vector using SimplifyDemanded Bits/VectorElts.
// Demand the elt/bit if any of the original elts/bits are demanded.
// TODO - bigendian once we have test coverage.
if (SrcVT.isVector() && (BitWidth % NumSrcEltBits) == 0 &&
TLO.DAG.getDataLayout().isLittleEndian()) {
unsigned Scale = BitWidth / NumSrcEltBits;
unsigned NumSrcElts = SrcVT.getVectorNumElements();
APInt DemandedSrcBits = APInt::getNullValue(NumSrcEltBits);
APInt DemandedSrcElts = APInt::getNullValue(NumSrcElts);
for (unsigned i = 0; i != Scale; ++i) {
unsigned Offset = i * NumSrcEltBits;
APInt Sub = DemandedBits.extractBits(NumSrcEltBits, Offset);
if (!Sub.isNullValue()) {
DemandedSrcBits |= Sub;
for (unsigned j = 0; j != NumElts; ++j)
if (DemandedElts[j])
DemandedSrcElts.setBit((j * Scale) + i);
}
}
APInt KnownSrcUndef, KnownSrcZero;
if (SimplifyDemandedVectorElts(Src, DemandedSrcElts, KnownSrcUndef,
KnownSrcZero, TLO, Depth + 1))
return true;
KnownBits KnownSrcBits;
if (SimplifyDemandedBits(Src, DemandedSrcBits, DemandedSrcElts,
KnownSrcBits, TLO, Depth + 1))
return true;
} else if ((NumSrcEltBits % BitWidth) == 0 &&
TLO.DAG.getDataLayout().isLittleEndian()) {
unsigned Scale = NumSrcEltBits / BitWidth;
unsigned NumSrcElts = SrcVT.isVector() ? SrcVT.getVectorNumElements() : 1;
APInt DemandedSrcBits = APInt::getNullValue(NumSrcEltBits);
APInt DemandedSrcElts = APInt::getNullValue(NumSrcElts);
for (unsigned i = 0; i != NumElts; ++i)
if (DemandedElts[i]) {
unsigned Offset = (i % Scale) * BitWidth;
DemandedSrcBits.insertBits(DemandedBits, Offset);
DemandedSrcElts.setBit(i / Scale);
}
if (SrcVT.isVector()) {
APInt KnownSrcUndef, KnownSrcZero;
if (SimplifyDemandedVectorElts(Src, DemandedSrcElts, KnownSrcUndef,
KnownSrcZero, TLO, Depth + 1))
return true;
}
KnownBits KnownSrcBits;
if (SimplifyDemandedBits(Src, DemandedSrcBits, DemandedSrcElts,
KnownSrcBits, TLO, Depth + 1))
return true;
}
// If this is a bitcast, let computeKnownBits handle it. Only do this on a
// recursive call where Known may be useful to the caller.
if (Depth > 0) {
Known = TLO.DAG.computeKnownBits(Op, DemandedElts, Depth);
return false;
}
break;
}
case ISD::ADD:
case ISD::MUL:
case ISD::SUB: {
// Add, Sub, and Mul don't demand any bits in positions beyond that
// of the highest bit demanded of them.
SDValue Op0 = Op.getOperand(0), Op1 = Op.getOperand(1);
SDNodeFlags Flags = Op.getNode()->getFlags();
unsigned DemandedBitsLZ = DemandedBits.countLeadingZeros();
APInt LoMask = APInt::getLowBitsSet(BitWidth, BitWidth - DemandedBitsLZ);
if (SimplifyDemandedBits(Op0, LoMask, DemandedElts, Known2, TLO,
Depth + 1) ||
SimplifyDemandedBits(Op1, LoMask, DemandedElts, Known2, TLO,
Depth + 1) ||
// See if the operation should be performed at a smaller bit width.
ShrinkDemandedOp(Op, BitWidth, DemandedBits, TLO)) {
if (Flags.hasNoSignedWrap() || Flags.hasNoUnsignedWrap()) {
// Disable the nsw and nuw flags. We can no longer guarantee that we
// won't wrap after simplification.
Flags.setNoSignedWrap(false);
Flags.setNoUnsignedWrap(false);
SDValue NewOp =
TLO.DAG.getNode(Op.getOpcode(), dl, VT, Op0, Op1, Flags);
return TLO.CombineTo(Op, NewOp);
}
return true;
}
// Attempt to avoid multi-use ops if we don't need anything from them.
if (!LoMask.isAllOnesValue() || !DemandedElts.isAllOnesValue()) {
SDValue DemandedOp0 = SimplifyMultipleUseDemandedBits(
Op0, LoMask, DemandedElts, TLO.DAG, Depth + 1);
SDValue DemandedOp1 = SimplifyMultipleUseDemandedBits(
Op1, LoMask, DemandedElts, TLO.DAG, Depth + 1);
if (DemandedOp0 || DemandedOp1) {
Flags.setNoSignedWrap(false);
Flags.setNoUnsignedWrap(false);
Op0 = DemandedOp0 ? DemandedOp0 : Op0;
Op1 = DemandedOp1 ? DemandedOp1 : Op1;
SDValue NewOp =
TLO.DAG.getNode(Op.getOpcode(), dl, VT, Op0, Op1, Flags);
return TLO.CombineTo(Op, NewOp);
}
}
// If we have a constant operand, we may be able to turn it into -1 if we
// do not demand the high bits. This can make the constant smaller to
// encode, allow more general folding, or match specialized instruction
// patterns (eg, 'blsr' on x86). Don't bother changing 1 to -1 because that
// is probably not useful (and could be detrimental).
ConstantSDNode *C = isConstOrConstSplat(Op1);
APInt HighMask = APInt::getHighBitsSet(BitWidth, DemandedBitsLZ);
if (C && !C->isAllOnesValue() && !C->isOne() &&
(C->getAPIntValue() | HighMask).isAllOnesValue()) {
SDValue Neg1 = TLO.DAG.getAllOnesConstant(dl, VT);
// Disable the nsw and nuw flags. We can no longer guarantee that we
// won't wrap after simplification.
Flags.setNoSignedWrap(false);
Flags.setNoUnsignedWrap(false);
SDValue NewOp = TLO.DAG.getNode(Op.getOpcode(), dl, VT, Op0, Neg1, Flags);
return TLO.CombineTo(Op, NewOp);
}
LLVM_FALLTHROUGH;
}
default:
if (Op.getOpcode() >= ISD::BUILTIN_OP_END) {
if (SimplifyDemandedBitsForTargetNode(Op, DemandedBits, DemandedElts,
Known, TLO, Depth))
return true;
break;
}
// Just use computeKnownBits to compute output bits.
Known = TLO.DAG.computeKnownBits(Op, DemandedElts, Depth);
break;
}
// If we know the value of all of the demanded bits, return this as a
// constant.
if (DemandedBits.isSubsetOf(Known.Zero | Known.One)) {
// Avoid folding to a constant if any OpaqueConstant is involved.
const SDNode *N = Op.getNode();
for (SDNodeIterator I = SDNodeIterator::begin(N),
E = SDNodeIterator::end(N);
I != E; ++I) {
SDNode *Op = *I;
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op))
if (C->isOpaque())
return false;
}
// TODO: Handle float bits as well.
if (VT.isInteger())
return TLO.CombineTo(Op, TLO.DAG.getConstant(Known.One, dl, VT));
}
return false;
}
bool TargetLowering::SimplifyDemandedVectorElts(SDValue Op,
const APInt &DemandedElts,
APInt &KnownUndef,
APInt &KnownZero,
DAGCombinerInfo &DCI) const {
SelectionDAG &DAG = DCI.DAG;
TargetLoweringOpt TLO(DAG, !DCI.isBeforeLegalize(),
!DCI.isBeforeLegalizeOps());
bool Simplified =
SimplifyDemandedVectorElts(Op, DemandedElts, KnownUndef, KnownZero, TLO);
if (Simplified) {
DCI.AddToWorklist(Op.getNode());
DCI.CommitTargetLoweringOpt(TLO);
}
return Simplified;
}
/// Given a vector binary operation and known undefined elements for each input
/// operand, compute whether each element of the output is undefined.
static APInt getKnownUndefForVectorBinop(SDValue BO, SelectionDAG &DAG,
const APInt &UndefOp0,
const APInt &UndefOp1) {
EVT VT = BO.getValueType();
assert(DAG.getTargetLoweringInfo().isBinOp(BO.getOpcode()) && VT.isVector() &&
"Vector binop only");
EVT EltVT = VT.getVectorElementType();
unsigned NumElts = VT.getVectorNumElements();
assert(UndefOp0.getBitWidth() == NumElts &&
UndefOp1.getBitWidth() == NumElts && "Bad type for undef analysis");
auto getUndefOrConstantElt = [&](SDValue V, unsigned Index,
const APInt &UndefVals) {
if (UndefVals[Index])
return DAG.getUNDEF(EltVT);
if (auto *BV = dyn_cast<BuildVectorSDNode>(V)) {
// Try hard to make sure that the getNode() call is not creating temporary
// nodes. Ignore opaque integers because they do not constant fold.
SDValue Elt = BV->getOperand(Index);
auto *C = dyn_cast<ConstantSDNode>(Elt);
if (isa<ConstantFPSDNode>(Elt) || Elt.isUndef() || (C && !C->isOpaque()))
return Elt;
}
return SDValue();
};
APInt KnownUndef = APInt::getNullValue(NumElts);
for (unsigned i = 0; i != NumElts; ++i) {
// If both inputs for this element are either constant or undef and match
// the element type, compute the constant/undef result for this element of
// the vector.
// TODO: Ideally we would use FoldConstantArithmetic() here, but that does
// not handle FP constants. The code within getNode() should be refactored
// to avoid the danger of creating a bogus temporary node here.
SDValue C0 = getUndefOrConstantElt(BO.getOperand(0), i, UndefOp0);
SDValue C1 = getUndefOrConstantElt(BO.getOperand(1), i, UndefOp1);
if (C0 && C1 && C0.getValueType() == EltVT && C1.getValueType() == EltVT)
if (DAG.getNode(BO.getOpcode(), SDLoc(BO), EltVT, C0, C1).isUndef())
KnownUndef.setBit(i);
}
return KnownUndef;
}
bool TargetLowering::SimplifyDemandedVectorElts(
SDValue Op, const APInt &OriginalDemandedElts, APInt &KnownUndef,
APInt &KnownZero, TargetLoweringOpt &TLO, unsigned Depth,
bool AssumeSingleUse) const {
EVT VT = Op.getValueType();
unsigned Opcode = Op.getOpcode();
APInt DemandedElts = OriginalDemandedElts;
unsigned NumElts = DemandedElts.getBitWidth();
assert(VT.isVector() && "Expected vector op");
KnownUndef = KnownZero = APInt::getNullValue(NumElts);
// TODO: For now we assume we know nothing about scalable vectors.
if (VT.isScalableVector())
return false;
assert(VT.getVectorNumElements() == NumElts &&
"Mask size mismatches value type element count!");
// Undef operand.
if (Op.isUndef()) {
KnownUndef.setAllBits();
return false;
}
// If Op has other users, assume that all elements are needed.
if (!Op.getNode()->hasOneUse() && !AssumeSingleUse)
DemandedElts.setAllBits();
// Not demanding any elements from Op.
if (DemandedElts == 0) {
KnownUndef.setAllBits();
return TLO.CombineTo(Op, TLO.DAG.getUNDEF(VT));
}
// Limit search depth.
if (Depth >= SelectionDAG::MaxRecursionDepth)
return false;
SDLoc DL(Op);
unsigned EltSizeInBits = VT.getScalarSizeInBits();
// Helper for demanding the specified elements and all the bits of both binary
// operands.
auto SimplifyDemandedVectorEltsBinOp = [&](SDValue Op0, SDValue Op1) {
SDValue NewOp0 = SimplifyMultipleUseDemandedVectorElts(Op0, DemandedElts,
TLO.DAG, Depth + 1);
SDValue NewOp1 = SimplifyMultipleUseDemandedVectorElts(Op1, DemandedElts,
TLO.DAG, Depth + 1);
if (NewOp0 || NewOp1) {
SDValue NewOp = TLO.DAG.getNode(
Opcode, SDLoc(Op), VT, NewOp0 ? NewOp0 : Op0, NewOp1 ? NewOp1 : Op1);
return TLO.CombineTo(Op, NewOp);
}
return false;
};
switch (Opcode) {
case ISD::SCALAR_TO_VECTOR: {
if (!DemandedElts[0]) {
KnownUndef.setAllBits();
return TLO.CombineTo(Op, TLO.DAG.getUNDEF(VT));
}
KnownUndef.setHighBits(NumElts - 1);
break;
}
case ISD::BITCAST: {
SDValue Src = Op.getOperand(0);
EVT SrcVT = Src.getValueType();
// We only handle vectors here.
// TODO - investigate calling SimplifyDemandedBits/ComputeKnownBits?
if (!SrcVT.isVector())
break;
// Fast handling of 'identity' bitcasts.
unsigned NumSrcElts = SrcVT.getVectorNumElements();
if (NumSrcElts == NumElts)
return SimplifyDemandedVectorElts(Src, DemandedElts, KnownUndef,
KnownZero, TLO, Depth + 1);
APInt SrcZero, SrcUndef;
APInt SrcDemandedElts = APInt::getNullValue(NumSrcElts);
// Bitcast from 'large element' src vector to 'small element' vector, we
// must demand a source element if any DemandedElt maps to it.
if ((NumElts % NumSrcElts) == 0) {
unsigned Scale = NumElts / NumSrcElts;
for (unsigned i = 0; i != NumElts; ++i)
if (DemandedElts[i])
SrcDemandedElts.setBit(i / Scale);
if (SimplifyDemandedVectorElts(Src, SrcDemandedElts, SrcUndef, SrcZero,
TLO, Depth + 1))
return true;
// Try calling SimplifyDemandedBits, converting demanded elts to the bits
// of the large element.
// TODO - bigendian once we have test coverage.
if (TLO.DAG.getDataLayout().isLittleEndian()) {
unsigned SrcEltSizeInBits = SrcVT.getScalarSizeInBits();
APInt SrcDemandedBits = APInt::getNullValue(SrcEltSizeInBits);
for (unsigned i = 0; i != NumElts; ++i)
if (DemandedElts[i]) {
unsigned Ofs = (i % Scale) * EltSizeInBits;
SrcDemandedBits.setBits(Ofs, Ofs + EltSizeInBits);
}
KnownBits Known;
if (SimplifyDemandedBits(Src, SrcDemandedBits, SrcDemandedElts, Known,
TLO, Depth + 1))
return true;
}
// If the src element is zero/undef then all the output elements will be -
// only demanded elements are guaranteed to be correct.
for (unsigned i = 0; i != NumSrcElts; ++i) {
if (SrcDemandedElts[i]) {
if (SrcZero[i])
KnownZero.setBits(i * Scale, (i + 1) * Scale);
if (SrcUndef[i])
KnownUndef.setBits(i * Scale, (i + 1) * Scale);
}
}
}
// Bitcast from 'small element' src vector to 'large element' vector, we
// demand all smaller source elements covered by the larger demanded element
// of this vector.
if ((NumSrcElts % NumElts) == 0) {
unsigned Scale = NumSrcElts / NumElts;
for (unsigned i = 0; i != NumElts; ++i)
if (DemandedElts[i])
SrcDemandedElts.setBits(i * Scale, (i + 1) * Scale);
if (SimplifyDemandedVectorElts(Src, SrcDemandedElts, SrcUndef, SrcZero,
TLO, Depth + 1))
return true;
// If all the src elements covering an output element are zero/undef, then
// the output element will be as well, assuming it was demanded.
for (unsigned i = 0; i != NumElts; ++i) {
if (DemandedElts[i]) {
if (SrcZero.extractBits(Scale, i * Scale).isAllOnesValue())
KnownZero.setBit(i);
if (SrcUndef.extractBits(Scale, i * Scale).isAllOnesValue())
KnownUndef.setBit(i);
}
}
}
break;
}
case ISD::BUILD_VECTOR: {
// Check all elements and simplify any unused elements with UNDEF.
if (!DemandedElts.isAllOnesValue()) {
// Don't simplify BROADCASTS.
if (llvm::any_of(Op->op_values(),
[&](SDValue Elt) { return Op.getOperand(0) != Elt; })) {
SmallVector<SDValue, 32> Ops(Op->op_begin(), Op->op_end());
bool Updated = false;
for (unsigned i = 0; i != NumElts; ++i) {
if (!DemandedElts[i] && !Ops[i].isUndef()) {
Ops[i] = TLO.DAG.getUNDEF(Ops[0].getValueType());
KnownUndef.setBit(i);
Updated = true;
}
}
if (Updated)
return TLO.CombineTo(Op, TLO.DAG.getBuildVector(VT, DL, Ops));
}
}
for (unsigned i = 0; i != NumElts; ++i) {
SDValue SrcOp = Op.getOperand(i);
if (SrcOp.isUndef()) {
KnownUndef.setBit(i);
} else if (EltSizeInBits == SrcOp.getScalarValueSizeInBits() &&
(isNullConstant(SrcOp) || isNullFPConstant(SrcOp))) {
KnownZero.setBit(i);
}
}
break;
}
case ISD::CONCAT_VECTORS: {
EVT SubVT = Op.getOperand(0).getValueType();
unsigned NumSubVecs = Op.getNumOperands();
unsigned NumSubElts = SubVT.getVectorNumElements();
for (unsigned i = 0; i != NumSubVecs; ++i) {
SDValue SubOp = Op.getOperand(i);
APInt SubElts = DemandedElts.extractBits(NumSubElts, i * NumSubElts);
APInt SubUndef, SubZero;
if (SimplifyDemandedVectorElts(SubOp, SubElts, SubUndef, SubZero, TLO,
Depth + 1))
return true;
KnownUndef.insertBits(SubUndef, i * NumSubElts);
KnownZero.insertBits(SubZero, i * NumSubElts);
}
break;
}
case ISD::INSERT_SUBVECTOR: {
// Demand any elements from the subvector and the remainder from the src its
// inserted into.
SDValue Src = Op.getOperand(0);
SDValue Sub = Op.getOperand(1);
uint64_t Idx = Op.getConstantOperandVal(2);
unsigned NumSubElts = Sub.getValueType().getVectorNumElements();
APInt DemandedSubElts = DemandedElts.extractBits(NumSubElts, Idx);
APInt DemandedSrcElts = DemandedElts;
DemandedSrcElts.insertBits(APInt::getNullValue(NumSubElts), Idx);
APInt SubUndef, SubZero;
if (SimplifyDemandedVectorElts(Sub, DemandedSubElts, SubUndef, SubZero, TLO,
Depth + 1))
return true;
// If none of the src operand elements are demanded, replace it with undef.
if (!DemandedSrcElts && !Src.isUndef())
return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::INSERT_SUBVECTOR, DL, VT,
TLO.DAG.getUNDEF(VT), Sub,
Op.getOperand(2)));
if (SimplifyDemandedVectorElts(Src, DemandedSrcElts, KnownUndef, KnownZero,
TLO, Depth + 1))
return true;
KnownUndef.insertBits(SubUndef, Idx);
KnownZero.insertBits(SubZero, Idx);
// Attempt to avoid multi-use ops if we don't need anything from them.
if (!DemandedSrcElts.isAllOnesValue() ||
!DemandedSubElts.isAllOnesValue()) {
SDValue NewSrc = SimplifyMultipleUseDemandedVectorElts(
Src, DemandedSrcElts, TLO.DAG, Depth + 1);
SDValue NewSub = SimplifyMultipleUseDemandedVectorElts(
Sub, DemandedSubElts, TLO.DAG, Depth + 1);
if (NewSrc || NewSub) {
NewSrc = NewSrc ? NewSrc : Src;
NewSub = NewSub ? NewSub : Sub;
SDValue NewOp = TLO.DAG.getNode(Op.getOpcode(), SDLoc(Op), VT, NewSrc,
NewSub, Op.getOperand(2));
return TLO.CombineTo(Op, NewOp);
}
}
break;
}
case ISD::EXTRACT_SUBVECTOR: {
// Offset the demanded elts by the subvector index.
SDValue Src = Op.getOperand(0);
if (Src.getValueType().isScalableVector())
break;
uint64_t Idx = Op.getConstantOperandVal(1);
unsigned NumSrcElts = Src.getValueType().getVectorNumElements();
APInt DemandedSrcElts = DemandedElts.zextOrSelf(NumSrcElts).shl(Idx);
APInt SrcUndef, SrcZero;
if (SimplifyDemandedVectorElts(Src, DemandedSrcElts, SrcUndef, SrcZero, TLO,
Depth + 1))
return true;
KnownUndef = SrcUndef.extractBits(NumElts, Idx);
KnownZero = SrcZero.extractBits(NumElts, Idx);
// Attempt to avoid multi-use ops if we don't need anything from them.
if (!DemandedElts.isAllOnesValue()) {
SDValue NewSrc = SimplifyMultipleUseDemandedVectorElts(
Src, DemandedSrcElts, TLO.DAG, Depth + 1);
if (NewSrc) {
SDValue NewOp = TLO.DAG.getNode(Op.getOpcode(), SDLoc(Op), VT, NewSrc,
Op.getOperand(1));
return TLO.CombineTo(Op, NewOp);
}
}
break;
}
case ISD::INSERT_VECTOR_ELT: {
SDValue Vec = Op.getOperand(0);
SDValue Scl = Op.getOperand(1);
auto *CIdx = dyn_cast<ConstantSDNode>(Op.getOperand(2));
// For a legal, constant insertion index, if we don't need this insertion
// then strip it, else remove it from the demanded elts.
if (CIdx && CIdx->getAPIntValue().ult(NumElts)) {
unsigned Idx = CIdx->getZExtValue();
if (!DemandedElts[Idx])
return TLO.CombineTo(Op, Vec);
APInt DemandedVecElts(DemandedElts);
DemandedVecElts.clearBit(Idx);
if (SimplifyDemandedVectorElts(Vec, DemandedVecElts, KnownUndef,
KnownZero, TLO, Depth + 1))
return true;
KnownUndef.clearBit(Idx);
if (Scl.isUndef())
KnownUndef.setBit(Idx);
KnownZero.clearBit(Idx);
if (isNullConstant(Scl) || isNullFPConstant(Scl))
KnownZero.setBit(Idx);
break;
}
APInt VecUndef, VecZero;
if (SimplifyDemandedVectorElts(Vec, DemandedElts, VecUndef, VecZero, TLO,
Depth + 1))
return true;
// Without knowing the insertion index we can't set KnownUndef/KnownZero.
break;
}
case ISD::VSELECT: {
// Try to transform the select condition based on the current demanded
// elements.
// TODO: If a condition element is undef, we can choose from one arm of the
// select (and if one arm is undef, then we can propagate that to the
// result).
// TODO - add support for constant vselect masks (see IR version of this).
APInt UnusedUndef, UnusedZero;
if (SimplifyDemandedVectorElts(Op.getOperand(0), DemandedElts, UnusedUndef,
UnusedZero, TLO, Depth + 1))
return true;
// See if we can simplify either vselect operand.
APInt DemandedLHS(DemandedElts);
APInt DemandedRHS(DemandedElts);
APInt UndefLHS, ZeroLHS;
APInt UndefRHS, ZeroRHS;
if (SimplifyDemandedVectorElts(Op.getOperand(1), DemandedLHS, UndefLHS,
ZeroLHS, TLO, Depth + 1))
return true;
if (SimplifyDemandedVectorElts(Op.getOperand(2), DemandedRHS, UndefRHS,
ZeroRHS, TLO, Depth + 1))
return true;
KnownUndef = UndefLHS & UndefRHS;
KnownZero = ZeroLHS & ZeroRHS;
break;
}
case ISD::VECTOR_SHUFFLE: {
ArrayRef<int> ShuffleMask = cast<ShuffleVectorSDNode>(Op)->getMask();
// Collect demanded elements from shuffle operands..
APInt DemandedLHS(NumElts, 0);
APInt DemandedRHS(NumElts, 0);
for (unsigned i = 0; i != NumElts; ++i) {
int M = ShuffleMask[i];
if (M < 0 || !DemandedElts[i])
continue;
assert(0 <= M && M < (int)(2 * NumElts) && "Shuffle index out of range");
if (M < (int)NumElts)
DemandedLHS.setBit(M);
else
DemandedRHS.setBit(M - NumElts);
}
// See if we can simplify either shuffle operand.
APInt UndefLHS, ZeroLHS;
APInt UndefRHS, ZeroRHS;
if (SimplifyDemandedVectorElts(Op.getOperand(0), DemandedLHS, UndefLHS,
ZeroLHS, TLO, Depth + 1))
return true;
if (SimplifyDemandedVectorElts(Op.getOperand(1), DemandedRHS, UndefRHS,
ZeroRHS, TLO, Depth + 1))
return true;
// Simplify mask using undef elements from LHS/RHS.
bool Updated = false;
bool IdentityLHS = true, IdentityRHS = true;
SmallVector<int, 32> NewMask(ShuffleMask.begin(), ShuffleMask.end());
for (unsigned i = 0; i != NumElts; ++i) {
int &M = NewMask[i];
if (M < 0)
continue;
if (!DemandedElts[i] || (M < (int)NumElts && UndefLHS[M]) ||
(M >= (int)NumElts && UndefRHS[M - NumElts])) {
Updated = true;
M = -1;
}
IdentityLHS &= (M < 0) || (M == (int)i);
IdentityRHS &= (M < 0) || ((M - NumElts) == i);
}
// Update legal shuffle masks based on demanded elements if it won't reduce
// to Identity which can cause premature removal of the shuffle mask.
if (Updated && !IdentityLHS && !IdentityRHS && !TLO.LegalOps) {
SDValue LegalShuffle =
buildLegalVectorShuffle(VT, DL, Op.getOperand(0), Op.getOperand(1),
NewMask, TLO.DAG);
if (LegalShuffle)
return TLO.CombineTo(Op, LegalShuffle);
}
// Propagate undef/zero elements from LHS/RHS.
for (unsigned i = 0; i != NumElts; ++i) {
int M = ShuffleMask[i];
if (M < 0) {
KnownUndef.setBit(i);
} else if (M < (int)NumElts) {
if (UndefLHS[M])
KnownUndef.setBit(i);
if (ZeroLHS[M])
KnownZero.setBit(i);
} else {
if (UndefRHS[M - NumElts])
KnownUndef.setBit(i);
if (ZeroRHS[M - NumElts])
KnownZero.setBit(i);
}
}
break;
}
case ISD::ANY_EXTEND_VECTOR_INREG:
case ISD::SIGN_EXTEND_VECTOR_INREG:
case ISD::ZERO_EXTEND_VECTOR_INREG: {
APInt SrcUndef, SrcZero;
SDValue Src = Op.getOperand(0);
unsigned NumSrcElts = Src.getValueType().getVectorNumElements();
APInt DemandedSrcElts = DemandedElts.zextOrSelf(NumSrcElts);
if (SimplifyDemandedVectorElts(Src, DemandedSrcElts, SrcUndef, SrcZero, TLO,
Depth + 1))
return true;
KnownZero = SrcZero.zextOrTrunc(NumElts);
KnownUndef = SrcUndef.zextOrTrunc(NumElts);
if (Op.getOpcode() == ISD::ANY_EXTEND_VECTOR_INREG &&
Op.getValueSizeInBits() == Src.getValueSizeInBits() &&
DemandedSrcElts == 1 && TLO.DAG.getDataLayout().isLittleEndian()) {
// aext - if we just need the bottom element then we can bitcast.
return TLO.CombineTo(Op, TLO.DAG.getBitcast(VT, Src));
}
if (Op.getOpcode() == ISD::ZERO_EXTEND_VECTOR_INREG) {
// zext(undef) upper bits are guaranteed to be zero.
if (DemandedElts.isSubsetOf(KnownUndef))
return TLO.CombineTo(Op, TLO.DAG.getConstant(0, SDLoc(Op), VT));
KnownUndef.clearAllBits();
}
break;
}
// TODO: There are more binop opcodes that could be handled here - MIN,
// MAX, saturated math, etc.
case ISD::OR:
case ISD::XOR:
case ISD::ADD:
case ISD::SUB:
case ISD::FADD:
case ISD::FSUB:
case ISD::FMUL:
case ISD::FDIV:
case ISD::FREM: {
SDValue Op0 = Op.getOperand(0);
SDValue Op1 = Op.getOperand(1);
APInt UndefRHS, ZeroRHS;
if (SimplifyDemandedVectorElts(Op1, DemandedElts, UndefRHS, ZeroRHS, TLO,
Depth + 1))
return true;
APInt UndefLHS, ZeroLHS;
if (SimplifyDemandedVectorElts(Op0, DemandedElts, UndefLHS, ZeroLHS, TLO,
Depth + 1))
return true;
KnownZero = ZeroLHS & ZeroRHS;
KnownUndef = getKnownUndefForVectorBinop(Op, TLO.DAG, UndefLHS, UndefRHS);
// Attempt to avoid multi-use ops if we don't need anything from them.
// TODO - use KnownUndef to relax the demandedelts?
if (!DemandedElts.isAllOnesValue())
if (SimplifyDemandedVectorEltsBinOp(Op0, Op1))
return true;
break;
}
case ISD::SHL:
case ISD::SRL:
case ISD::SRA:
case ISD::ROTL:
case ISD::ROTR: {
SDValue Op0 = Op.getOperand(0);
SDValue Op1 = Op.getOperand(1);
APInt UndefRHS, ZeroRHS;
if (SimplifyDemandedVectorElts(Op1, DemandedElts, UndefRHS, ZeroRHS, TLO,
Depth + 1))
return true;
APInt UndefLHS, ZeroLHS;
if (SimplifyDemandedVectorElts(Op0, DemandedElts, UndefLHS, ZeroLHS, TLO,
Depth + 1))
return true;
KnownZero = ZeroLHS;
KnownUndef = UndefLHS & UndefRHS; // TODO: use getKnownUndefForVectorBinop?
// Attempt to avoid multi-use ops if we don't need anything from them.
// TODO - use KnownUndef to relax the demandedelts?
if (!DemandedElts.isAllOnesValue())
if (SimplifyDemandedVectorEltsBinOp(Op0, Op1))
return true;
break;
}
case ISD::MUL:
case ISD::AND: {
SDValue Op0 = Op.getOperand(0);
SDValue Op1 = Op.getOperand(1);
APInt SrcUndef, SrcZero;
if (SimplifyDemandedVectorElts(Op1, DemandedElts, SrcUndef, SrcZero, TLO,
Depth + 1))
return true;
if (SimplifyDemandedVectorElts(Op0, DemandedElts, KnownUndef, KnownZero,
TLO, Depth + 1))
return true;
// If either side has a zero element, then the result element is zero, even
// if the other is an UNDEF.
// TODO: Extend getKnownUndefForVectorBinop to also deal with known zeros
// and then handle 'and' nodes with the rest of the binop opcodes.
KnownZero |= SrcZero;
KnownUndef &= SrcUndef;
KnownUndef &= ~KnownZero;
// Attempt to avoid multi-use ops if we don't need anything from them.
// TODO - use KnownUndef to relax the demandedelts?
if (!DemandedElts.isAllOnesValue())
if (SimplifyDemandedVectorEltsBinOp(Op0, Op1))
return true;
break;
}
case ISD::TRUNCATE:
case ISD::SIGN_EXTEND:
case ISD::ZERO_EXTEND:
if (SimplifyDemandedVectorElts(Op.getOperand(0), DemandedElts, KnownUndef,
KnownZero, TLO, Depth + 1))
return true;
if (Op.getOpcode() == ISD::ZERO_EXTEND) {
// zext(undef) upper bits are guaranteed to be zero.
if (DemandedElts.isSubsetOf(KnownUndef))
return TLO.CombineTo(Op, TLO.DAG.getConstant(0, SDLoc(Op), VT));
KnownUndef.clearAllBits();
}
break;
default: {
if (Op.getOpcode() >= ISD::BUILTIN_OP_END) {
if (SimplifyDemandedVectorEltsForTargetNode(Op, DemandedElts, KnownUndef,
KnownZero, TLO, Depth))
return true;
} else {
KnownBits Known;
APInt DemandedBits = APInt::getAllOnesValue(EltSizeInBits);
if (SimplifyDemandedBits(Op, DemandedBits, OriginalDemandedElts, Known,
TLO, Depth, AssumeSingleUse))
return true;
}
break;
}
}
assert((KnownUndef & KnownZero) == 0 && "Elements flagged as undef AND zero");
// Constant fold all undef cases.
// TODO: Handle zero cases as well.
if (DemandedElts.isSubsetOf(KnownUndef))
return TLO.CombineTo(Op, TLO.DAG.getUNDEF(VT));
return false;
}
/// Determine which of the bits specified in Mask are known to be either zero or
/// one and return them in the Known.
void TargetLowering::computeKnownBitsForTargetNode(const SDValue Op,
KnownBits &Known,
const APInt &DemandedElts,
const SelectionDAG &DAG,
unsigned Depth) const {
assert((Op.getOpcode() >= ISD::BUILTIN_OP_END ||
Op.getOpcode() == ISD::INTRINSIC_WO_CHAIN ||
Op.getOpcode() == ISD::INTRINSIC_W_CHAIN ||
Op.getOpcode() == ISD::INTRINSIC_VOID) &&
"Should use MaskedValueIsZero if you don't know whether Op"
" is a target node!");
Known.resetAll();
}
void TargetLowering::computeKnownBitsForTargetInstr(
GISelKnownBits &Analysis, Register R, KnownBits &Known,
const APInt &DemandedElts, const MachineRegisterInfo &MRI,
unsigned Depth) const {
Known.resetAll();
}
void TargetLowering::computeKnownBitsForFrameIndex(
const int FrameIdx, KnownBits &Known, const MachineFunction &MF) const {
// The low bits are known zero if the pointer is aligned.
Known.Zero.setLowBits(Log2(MF.getFrameInfo().getObjectAlign(FrameIdx)));
}
Align TargetLowering::computeKnownAlignForTargetInstr(
GISelKnownBits &Analysis, Register R, const MachineRegisterInfo &MRI,
unsigned Depth) const {
return Align(1);
}
/// This method can be implemented by targets that want to expose additional
/// information about sign bits to the DAG Combiner.
unsigned TargetLowering::ComputeNumSignBitsForTargetNode(SDValue Op,
const APInt &,
const SelectionDAG &,
unsigned Depth) const {
assert((Op.getOpcode() >= ISD::BUILTIN_OP_END ||
Op.getOpcode() == ISD::INTRINSIC_WO_CHAIN ||
Op.getOpcode() == ISD::INTRINSIC_W_CHAIN ||
Op.getOpcode() == ISD::INTRINSIC_VOID) &&
"Should use ComputeNumSignBits if you don't know whether Op"
" is a target node!");
return 1;
}
unsigned TargetLowering::computeNumSignBitsForTargetInstr(
GISelKnownBits &Analysis, Register R, const APInt &DemandedElts,
const MachineRegisterInfo &MRI, unsigned Depth) const {
return 1;
}
bool TargetLowering::SimplifyDemandedVectorEltsForTargetNode(
SDValue Op, const APInt &DemandedElts, APInt &KnownUndef, APInt &KnownZero,
TargetLoweringOpt &TLO, unsigned Depth) const {
assert((Op.getOpcode() >= ISD::BUILTIN_OP_END ||
Op.getOpcode() == ISD::INTRINSIC_WO_CHAIN ||
Op.getOpcode() == ISD::INTRINSIC_W_CHAIN ||
Op.getOpcode() == ISD::INTRINSIC_VOID) &&
"Should use SimplifyDemandedVectorElts if you don't know whether Op"
" is a target node!");
return false;
}
bool TargetLowering::SimplifyDemandedBitsForTargetNode(
SDValue Op, const APInt &DemandedBits, const APInt &DemandedElts,
KnownBits &Known, TargetLoweringOpt &TLO, unsigned Depth) const {
assert((Op.getOpcode() >= ISD::BUILTIN_OP_END ||
Op.getOpcode() == ISD::INTRINSIC_WO_CHAIN ||
Op.getOpcode() == ISD::INTRINSIC_W_CHAIN ||
Op.getOpcode() == ISD::INTRINSIC_VOID) &&
"Should use SimplifyDemandedBits if you don't know whether Op"
" is a target node!");
computeKnownBitsForTargetNode(Op, Known, DemandedElts, TLO.DAG, Depth);
return false;
}
SDValue TargetLowering::SimplifyMultipleUseDemandedBitsForTargetNode(
SDValue Op, const APInt &DemandedBits, const APInt &DemandedElts,
SelectionDAG &DAG, unsigned Depth) const {
assert(
(Op.getOpcode() >= ISD::BUILTIN_OP_END ||
Op.getOpcode() == ISD::INTRINSIC_WO_CHAIN ||
Op.getOpcode() == ISD::INTRINSIC_W_CHAIN ||
Op.getOpcode() == ISD::INTRINSIC_VOID) &&
"Should use SimplifyMultipleUseDemandedBits if you don't know whether Op"
" is a target node!");
return SDValue();
}
SDValue
TargetLowering::buildLegalVectorShuffle(EVT VT, const SDLoc &DL, SDValue N0,
SDValue N1, MutableArrayRef<int> Mask,
SelectionDAG &DAG) const {
bool LegalMask = isShuffleMaskLegal(Mask, VT);
if (!LegalMask) {
std::swap(N0, N1);
ShuffleVectorSDNode::commuteMask(Mask);
LegalMask = isShuffleMaskLegal(Mask, VT);
}
if (!LegalMask)
return SDValue();
return DAG.getVectorShuffle(VT, DL, N0, N1, Mask);
}
const Constant *TargetLowering::getTargetConstantFromLoad(LoadSDNode*) const {
return nullptr;
}
bool TargetLowering::isKnownNeverNaNForTargetNode(SDValue Op,
const SelectionDAG &DAG,
bool SNaN,
unsigned Depth) const {
assert((Op.getOpcode() >= ISD::BUILTIN_OP_END ||
Op.getOpcode() == ISD::INTRINSIC_WO_CHAIN ||
Op.getOpcode() == ISD::INTRINSIC_W_CHAIN ||
Op.getOpcode() == ISD::INTRINSIC_VOID) &&
"Should use isKnownNeverNaN if you don't know whether Op"
" is a target node!");
return false;
}
// FIXME: Ideally, this would use ISD::isConstantSplatVector(), but that must
// work with truncating build vectors and vectors with elements of less than
// 8 bits.
bool TargetLowering::isConstTrueVal(const SDNode *N) const {
if (!N)
return false;
APInt CVal;
if (auto *CN = dyn_cast<ConstantSDNode>(N)) {
CVal = CN->getAPIntValue();
} else if (auto *BV = dyn_cast<BuildVectorSDNode>(N)) {
auto *CN = BV->getConstantSplatNode();
if (!CN)
return false;
// If this is a truncating build vector, truncate the splat value.
// Otherwise, we may fail to match the expected values below.
unsigned BVEltWidth = BV->getValueType(0).getScalarSizeInBits();
CVal = CN->getAPIntValue();
if (BVEltWidth < CVal.getBitWidth())
CVal = CVal.trunc(BVEltWidth);
} else {
return false;
}
switch (getBooleanContents(N->getValueType(0))) {
case UndefinedBooleanContent:
return CVal[0];
case ZeroOrOneBooleanContent:
return CVal.isOneValue();
case ZeroOrNegativeOneBooleanContent:
return CVal.isAllOnesValue();
}
llvm_unreachable("Invalid boolean contents");
}
bool TargetLowering::isConstFalseVal(const SDNode *N) const {
if (!N)
return false;
const ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N);
if (!CN) {
const BuildVectorSDNode *BV = dyn_cast<BuildVectorSDNode>(N);
if (!BV)
return false;
// Only interested in constant splats, we don't care about undef
// elements in identifying boolean constants and getConstantSplatNode
// returns NULL if all ops are undef;
CN = BV->getConstantSplatNode();
if (!CN)
return false;
}
if (getBooleanContents(N->getValueType(0)) == UndefinedBooleanContent)
return !CN->getAPIntValue()[0];
return CN->isNullValue();
}
bool TargetLowering::isExtendedTrueVal(const ConstantSDNode *N, EVT VT,
bool SExt) const {
if (VT == MVT::i1)
return N->isOne();
TargetLowering::BooleanContent Cnt = getBooleanContents(VT);
switch (Cnt) {
case TargetLowering::ZeroOrOneBooleanContent:
// An extended value of 1 is always true, unless its original type is i1,
// in which case it will be sign extended to -1.
return (N->isOne() && !SExt) || (SExt && (N->getValueType(0) != MVT::i1));
case TargetLowering::UndefinedBooleanContent:
case TargetLowering::ZeroOrNegativeOneBooleanContent:
return N->isAllOnesValue() && SExt;
}
llvm_unreachable("Unexpected enumeration.");
}
/// This helper function of SimplifySetCC tries to optimize the comparison when
/// either operand of the SetCC node is a bitwise-and instruction.
SDValue TargetLowering::foldSetCCWithAnd(EVT VT, SDValue N0, SDValue N1,
ISD::CondCode Cond, const SDLoc &DL,
DAGCombinerInfo &DCI) const {
// Match these patterns in any of their permutations:
// (X & Y) == Y
// (X & Y) != Y
if (N1.getOpcode() == ISD::AND && N0.getOpcode() != ISD::AND)
std::swap(N0, N1);
EVT OpVT = N0.getValueType();
if (N0.getOpcode() != ISD::AND || !OpVT.isInteger() ||
(Cond != ISD::SETEQ && Cond != ISD::SETNE))
return SDValue();
SDValue X, Y;
if (N0.getOperand(0) == N1) {
X = N0.getOperand(1);
Y = N0.getOperand(0);
} else if (N0.getOperand(1) == N1) {
X = N0.getOperand(0);
Y = N0.getOperand(1);
} else {
return SDValue();
}
SelectionDAG &DAG = DCI.DAG;
SDValue Zero = DAG.getConstant(0, DL, OpVT);
if (DAG.isKnownToBeAPowerOfTwo(Y)) {
// Simplify X & Y == Y to X & Y != 0 if Y has exactly one bit set.
// Note that where Y is variable and is known to have at most one bit set
// (for example, if it is Z & 1) we cannot do this; the expressions are not
// equivalent when Y == 0.
assert(OpVT.isInteger());
Cond = ISD::getSetCCInverse(Cond, OpVT);
if (DCI.isBeforeLegalizeOps() ||
isCondCodeLegal(Cond, N0.getSimpleValueType()))
return DAG.getSetCC(DL, VT, N0, Zero, Cond);
} else if (N0.hasOneUse() && hasAndNotCompare(Y)) {
// If the target supports an 'and-not' or 'and-complement' logic operation,
// try to use that to make a comparison operation more efficient.
// But don't do this transform if the mask is a single bit because there are
// more efficient ways to deal with that case (for example, 'bt' on x86 or
// 'rlwinm' on PPC).
// Bail out if the compare operand that we want to turn into a zero is
// already a zero (otherwise, infinite loop).
auto *YConst = dyn_cast<ConstantSDNode>(Y);
if (YConst && YConst->isNullValue())
return SDValue();
// Transform this into: ~X & Y == 0.
SDValue NotX = DAG.getNOT(SDLoc(X), X, OpVT);
SDValue NewAnd = DAG.getNode(ISD::AND, SDLoc(N0), OpVT, NotX, Y);
return DAG.getSetCC(DL, VT, NewAnd, Zero, Cond);
}
return SDValue();
}
/// There are multiple IR patterns that could be checking whether certain
/// truncation of a signed number would be lossy or not. The pattern which is
/// best at IR level, may not lower optimally. Thus, we want to unfold it.
/// We are looking for the following pattern: (KeptBits is a constant)
/// (add %x, (1 << (KeptBits-1))) srccond (1 << KeptBits)
/// KeptBits won't be bitwidth(x), that will be constant-folded to true/false.
/// KeptBits also can't be 1, that would have been folded to %x dstcond 0
/// We will unfold it into the natural trunc+sext pattern:
/// ((%x << C) a>> C) dstcond %x
/// Where C = bitwidth(x) - KeptBits and C u< bitwidth(x)
SDValue TargetLowering::optimizeSetCCOfSignedTruncationCheck(
EVT SCCVT, SDValue N0, SDValue N1, ISD::CondCode Cond, DAGCombinerInfo &DCI,
const SDLoc &DL) const {
// We must be comparing with a constant.
ConstantSDNode *C1;
if (!(C1 = dyn_cast<ConstantSDNode>(N1)))
return SDValue();
// N0 should be: add %x, (1 << (KeptBits-1))
if (N0->getOpcode() != ISD::ADD)
return SDValue();
// And we must be 'add'ing a constant.
ConstantSDNode *C01;
if (!(C01 = dyn_cast<ConstantSDNode>(N0->getOperand(1))))
return SDValue();
SDValue X = N0->getOperand(0);
EVT XVT = X.getValueType();
// Validate constants ...
APInt I1 = C1->getAPIntValue();
ISD::CondCode NewCond;
if (Cond == ISD::CondCode::SETULT) {
NewCond = ISD::CondCode::SETEQ;
} else if (Cond == ISD::CondCode::SETULE) {
NewCond = ISD::CondCode::SETEQ;
// But need to 'canonicalize' the constant.
I1 += 1;
} else if (Cond == ISD::CondCode::SETUGT) {
NewCond = ISD::CondCode::SETNE;
// But need to 'canonicalize' the constant.
I1 += 1;
} else if (Cond == ISD::CondCode::SETUGE) {
NewCond = ISD::CondCode::SETNE;
} else
return SDValue();
APInt I01 = C01->getAPIntValue();
auto checkConstants = [&I1, &I01]() -> bool {
// Both of them must be power-of-two, and the constant from setcc is bigger.
return I1.ugt(I01) && I1.isPowerOf2() && I01.isPowerOf2();
};
if (checkConstants()) {
// Great, e.g. got icmp ult i16 (add i16 %x, 128), 256
} else {
// What if we invert constants? (and the target predicate)
I1.negate();
I01.negate();
assert(XVT.isInteger());
NewCond = getSetCCInverse(NewCond, XVT);
if (!checkConstants())
return SDValue();
// Great, e.g. got icmp uge i16 (add i16 %x, -128), -256
}
// They are power-of-two, so which bit is set?
const unsigned KeptBits = I1.logBase2();
const unsigned KeptBitsMinusOne = I01.logBase2();
// Magic!
if (KeptBits != (KeptBitsMinusOne + 1))
return SDValue();
assert(KeptBits > 0 && KeptBits < XVT.getSizeInBits() && "unreachable");
// We don't want to do this in every single case.
SelectionDAG &DAG = DCI.DAG;
if (!DAG.getTargetLoweringInfo().shouldTransformSignedTruncationCheck(
XVT, KeptBits))
return SDValue();
const unsigned MaskedBits = XVT.getSizeInBits() - KeptBits;
assert(MaskedBits > 0 && MaskedBits < XVT.getSizeInBits() && "unreachable");
// Unfold into: ((%x << C) a>> C) cond %x
// Where 'cond' will be either 'eq' or 'ne'.
SDValue ShiftAmt = DAG.getConstant(MaskedBits, DL, XVT);
SDValue T0 = DAG.getNode(ISD::SHL, DL, XVT, X, ShiftAmt);
SDValue T1 = DAG.getNode(ISD::SRA, DL, XVT, T0, ShiftAmt);
SDValue T2 = DAG.getSetCC(DL, SCCVT, T1, X, NewCond);
return T2;
}
// (X & (C l>>/<< Y)) ==/!= 0 --> ((X <</l>> Y) & C) ==/!= 0
SDValue TargetLowering::optimizeSetCCByHoistingAndByConstFromLogicalShift(
EVT SCCVT, SDValue N0, SDValue N1C, ISD::CondCode Cond,
DAGCombinerInfo &DCI, const SDLoc &DL) const {
assert(isConstOrConstSplat(N1C) &&
isConstOrConstSplat(N1C)->getAPIntValue().isNullValue() &&
"Should be a comparison with 0.");
assert((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
"Valid only for [in]equality comparisons.");
unsigned NewShiftOpcode;
SDValue X, C, Y;
SelectionDAG &DAG = DCI.DAG;
const TargetLowering &TLI = DAG.getTargetLoweringInfo();
// Look for '(C l>>/<< Y)'.
auto Match = [&NewShiftOpcode, &X, &C, &Y, &TLI, &DAG](SDValue V) {
// The shift should be one-use.
if (!V.hasOneUse())
return false;
unsigned OldShiftOpcode = V.getOpcode();
switch (OldShiftOpcode) {
case ISD::SHL:
NewShiftOpcode = ISD::SRL;
break;
case ISD::SRL:
NewShiftOpcode = ISD::SHL;
break;
default:
return false; // must be a logical shift.
}
// We should be shifting a constant.
// FIXME: best to use isConstantOrConstantVector().
C = V.getOperand(0);
ConstantSDNode *CC =
isConstOrConstSplat(C, /*AllowUndefs=*/true, /*AllowTruncation=*/true);
if (!CC)
return false;
Y = V.getOperand(1);
ConstantSDNode *XC =
isConstOrConstSplat(X, /*AllowUndefs=*/true, /*AllowTruncation=*/true);
return TLI.shouldProduceAndByConstByHoistingConstFromShiftsLHSOfAnd(
X, XC, CC, Y, OldShiftOpcode, NewShiftOpcode, DAG);
};
// LHS of comparison should be an one-use 'and'.
if (N0.getOpcode() != ISD::AND || !N0.hasOneUse())
return SDValue();
X = N0.getOperand(0);
SDValue Mask = N0.getOperand(1);
// 'and' is commutative!
if (!Match(Mask)) {
std::swap(X, Mask);
if (!Match(Mask))
return SDValue();
}
EVT VT = X.getValueType();
// Produce:
// ((X 'OppositeShiftOpcode' Y) & C) Cond 0
SDValue T0 = DAG.getNode(NewShiftOpcode, DL, VT, X, Y);
SDValue T1 = DAG.getNode(ISD::AND, DL, VT, T0, C);
SDValue T2 = DAG.getSetCC(DL, SCCVT, T1, N1C, Cond);
return T2;
}
/// Try to fold an equality comparison with a {add/sub/xor} binary operation as
/// the 1st operand (N0). Callers are expected to swap the N0/N1 parameters to
/// handle the commuted versions of these patterns.
SDValue TargetLowering::foldSetCCWithBinOp(EVT VT, SDValue N0, SDValue N1,
ISD::CondCode Cond, const SDLoc &DL,
DAGCombinerInfo &DCI) const {
unsigned BOpcode = N0.getOpcode();
assert((BOpcode == ISD::ADD || BOpcode == ISD::SUB || BOpcode == ISD::XOR) &&
"Unexpected binop");
assert((Cond == ISD::SETEQ || Cond == ISD::SETNE) && "Unexpected condcode");
// (X + Y) == X --> Y == 0
// (X - Y) == X --> Y == 0
// (X ^ Y) == X --> Y == 0
SelectionDAG &DAG = DCI.DAG;
EVT OpVT = N0.getValueType();
SDValue X = N0.getOperand(0);
SDValue Y = N0.getOperand(1);
if (X == N1)
return DAG.getSetCC(DL, VT, Y, DAG.getConstant(0, DL, OpVT), Cond);
if (Y != N1)
return SDValue();
// (X + Y) == Y --> X == 0
// (X ^ Y) == Y --> X == 0
if (BOpcode == ISD::ADD || BOpcode == ISD::XOR)
return DAG.getSetCC(DL, VT, X, DAG.getConstant(0, DL, OpVT), Cond);
// The shift would not be valid if the operands are boolean (i1).
if (!N0.hasOneUse() || OpVT.getScalarSizeInBits() == 1)
return SDValue();
// (X - Y) == Y --> X == Y << 1
EVT ShiftVT = getShiftAmountTy(OpVT, DAG.getDataLayout(),
!DCI.isBeforeLegalize());
SDValue One = DAG.getConstant(1, DL, ShiftVT);
SDValue YShl1 = DAG.getNode(ISD::SHL, DL, N1.getValueType(), Y, One);
if (!DCI.isCalledByLegalizer())
DCI.AddToWorklist(YShl1.getNode());
return DAG.getSetCC(DL, VT, X, YShl1, Cond);
}
/// Try to simplify a setcc built with the specified operands and cc. If it is
/// unable to simplify it, return a null SDValue.
SDValue TargetLowering::SimplifySetCC(EVT VT, SDValue N0, SDValue N1,
ISD::CondCode Cond, bool foldBooleans,
DAGCombinerInfo &DCI,
const SDLoc &dl) const {
SelectionDAG &DAG = DCI.DAG;
const DataLayout &Layout = DAG.getDataLayout();
EVT OpVT = N0.getValueType();
// Constant fold or commute setcc.
if (SDValue Fold = DAG.FoldSetCC(VT, N0, N1, Cond, dl))
return Fold;
// Ensure that the constant occurs on the RHS and fold constant comparisons.
// TODO: Handle non-splat vector constants. All undef causes trouble.
ISD::CondCode SwappedCC = ISD::getSetCCSwappedOperands(Cond);
if (isConstOrConstSplat(N0) &&
(DCI.isBeforeLegalizeOps() ||
isCondCodeLegal(SwappedCC, N0.getSimpleValueType())))
return DAG.getSetCC(dl, VT, N1, N0, SwappedCC);
// If we have a subtract with the same 2 non-constant operands as this setcc
// -- but in reverse order -- then try to commute the operands of this setcc
// to match. A matching pair of setcc (cmp) and sub may be combined into 1
// instruction on some targets.
if (!isConstOrConstSplat(N0) && !isConstOrConstSplat(N1) &&
(DCI.isBeforeLegalizeOps() ||
isCondCodeLegal(SwappedCC, N0.getSimpleValueType())) &&
DAG.getNodeIfExists(ISD::SUB, DAG.getVTList(OpVT), { N1, N0 } ) &&
!DAG.getNodeIfExists(ISD::SUB, DAG.getVTList(OpVT), { N0, N1 } ))
return DAG.getSetCC(dl, VT, N1, N0, SwappedCC);
if (auto *N1C = dyn_cast<ConstantSDNode>(N1.getNode())) {
const APInt &C1 = N1C->getAPIntValue();
// If the LHS is '(srl (ctlz x), 5)', the RHS is 0/1, and this is an
// equality comparison, then we're just comparing whether X itself is
// zero.
if (N0.getOpcode() == ISD::SRL && (C1.isNullValue() || C1.isOneValue()) &&
N0.getOperand(0).getOpcode() == ISD::CTLZ &&
N0.getOperand(1).getOpcode() == ISD::Constant) {
const APInt &ShAmt = N0.getConstantOperandAPInt(1);
if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
ShAmt == Log2_32(N0.getValueSizeInBits())) {
if ((C1 == 0) == (Cond == ISD::SETEQ)) {
// (srl (ctlz x), 5) == 0 -> X != 0
// (srl (ctlz x), 5) != 1 -> X != 0
Cond = ISD::SETNE;
} else {
// (srl (ctlz x), 5) != 0 -> X == 0
// (srl (ctlz x), 5) == 1 -> X == 0
Cond = ISD::SETEQ;
}
SDValue Zero = DAG.getConstant(0, dl, N0.getValueType());
return DAG.getSetCC(dl, VT, N0.getOperand(0).getOperand(0),
Zero, Cond);
}
}
SDValue CTPOP = N0;
// Look through truncs that don't change the value of a ctpop.
if (N0.hasOneUse() && N0.getOpcode() == ISD::TRUNCATE)
CTPOP = N0.getOperand(0);
if (CTPOP.hasOneUse() && CTPOP.getOpcode() == ISD::CTPOP &&
(N0 == CTPOP ||
N0.getValueSizeInBits() > Log2_32_Ceil(CTPOP.getValueSizeInBits()))) {
EVT CTVT = CTPOP.getValueType();
SDValue CTOp = CTPOP.getOperand(0);
// (ctpop x) u< 2 -> (x & x-1) == 0
// (ctpop x) u> 1 -> (x & x-1) != 0
if ((Cond == ISD::SETULT && C1 == 2) || (Cond == ISD::SETUGT && C1 == 1)){
SDValue NegOne = DAG.getAllOnesConstant(dl, CTVT);
SDValue Add = DAG.getNode(ISD::ADD, dl, CTVT, CTOp, NegOne);
SDValue And = DAG.getNode(ISD::AND, dl, CTVT, CTOp, Add);
ISD::CondCode CC = Cond == ISD::SETULT ? ISD::SETEQ : ISD::SETNE;
return DAG.getSetCC(dl, VT, And, DAG.getConstant(0, dl, CTVT), CC);
}
// If ctpop is not supported, expand a power-of-2 comparison based on it.
if (C1 == 1 && !isOperationLegalOrCustom(ISD::CTPOP, CTVT) &&
(Cond == ISD::SETEQ || Cond == ISD::SETNE)) {
// (ctpop x) == 1 --> (x != 0) && ((x & x-1) == 0)
// (ctpop x) != 1 --> (x == 0) || ((x & x-1) != 0)
SDValue Zero = DAG.getConstant(0, dl, CTVT);
SDValue NegOne = DAG.getAllOnesConstant(dl, CTVT);
assert(CTVT.isInteger());
ISD::CondCode InvCond = ISD::getSetCCInverse(Cond, CTVT);
SDValue Add = DAG.getNode(ISD::ADD, dl, CTVT, CTOp, NegOne);
SDValue And = DAG.getNode(ISD::AND, dl, CTVT, CTOp, Add);
SDValue LHS = DAG.getSetCC(dl, VT, CTOp, Zero, InvCond);
SDValue RHS = DAG.getSetCC(dl, VT, And, Zero, Cond);
unsigned LogicOpcode = Cond == ISD::SETEQ ? ISD::AND : ISD::OR;
return DAG.getNode(LogicOpcode, dl, VT, LHS, RHS);
}
}
// (zext x) == C --> x == (trunc C)
// (sext x) == C --> x == (trunc C)
if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
DCI.isBeforeLegalize() && N0->hasOneUse()) {
unsigned MinBits = N0.getValueSizeInBits();
SDValue PreExt;
bool Signed = false;
if (N0->getOpcode() == ISD::ZERO_EXTEND) {
// ZExt
MinBits = N0->getOperand(0).getValueSizeInBits();
PreExt = N0->getOperand(0);
} else if (N0->getOpcode() == ISD::AND) {
// DAGCombine turns costly ZExts into ANDs
if (auto *C = dyn_cast<ConstantSDNode>(N0->getOperand(1)))
if ((C->getAPIntValue()+1).isPowerOf2()) {
MinBits = C->getAPIntValue().countTrailingOnes();
PreExt = N0->getOperand(0);
}
} else if (N0->getOpcode() == ISD::SIGN_EXTEND) {
// SExt
MinBits = N0->getOperand(0).getValueSizeInBits();
PreExt = N0->getOperand(0);
Signed = true;
} else if (auto *LN0 = dyn_cast<LoadSDNode>(N0)) {
// ZEXTLOAD / SEXTLOAD
if (LN0->getExtensionType() == ISD::ZEXTLOAD) {
MinBits = LN0->getMemoryVT().getSizeInBits();
PreExt = N0;
} else if (LN0->getExtensionType() == ISD::SEXTLOAD) {
Signed = true;
MinBits = LN0->getMemoryVT().getSizeInBits();
PreExt = N0;
}
}
// Figure out how many bits we need to preserve this constant.
unsigned ReqdBits = Signed ?
C1.getBitWidth() - C1.getNumSignBits() + 1 :
C1.getActiveBits();
// Make sure we're not losing bits from the constant.
if (MinBits > 0 &&
MinBits < C1.getBitWidth() &&
MinBits >= ReqdBits) {
EVT MinVT = EVT::getIntegerVT(*DAG.getContext(), MinBits);
if (isTypeDesirableForOp(ISD::SETCC, MinVT)) {
// Will get folded away.
SDValue Trunc = DAG.getNode(ISD::TRUNCATE, dl, MinVT, PreExt);
if (MinBits == 1 && C1 == 1)
// Invert the condition.
return DAG.getSetCC(dl, VT, Trunc, DAG.getConstant(0, dl, MVT::i1),
Cond == ISD::SETEQ ? ISD::SETNE : ISD::SETEQ);
SDValue C = DAG.getConstant(C1.trunc(MinBits), dl, MinVT);
return DAG.getSetCC(dl, VT, Trunc, C, Cond);
}
// If truncating the setcc operands is not desirable, we can still
// simplify the expression in some cases:
// setcc ([sz]ext (setcc x, y, cc)), 0, setne) -> setcc (x, y, cc)
// setcc ([sz]ext (setcc x, y, cc)), 0, seteq) -> setcc (x, y, inv(cc))
// setcc (zext (setcc x, y, cc)), 1, setne) -> setcc (x, y, inv(cc))
// setcc (zext (setcc x, y, cc)), 1, seteq) -> setcc (x, y, cc)
// setcc (sext (setcc x, y, cc)), -1, setne) -> setcc (x, y, inv(cc))
// setcc (sext (setcc x, y, cc)), -1, seteq) -> setcc (x, y, cc)
SDValue TopSetCC = N0->getOperand(0);
unsigned N0Opc = N0->getOpcode();
bool SExt = (N0Opc == ISD::SIGN_EXTEND);
if (TopSetCC.getValueType() == MVT::i1 && VT == MVT::i1 &&
TopSetCC.getOpcode() == ISD::SETCC &&
(N0Opc == ISD::ZERO_EXTEND || N0Opc == ISD::SIGN_EXTEND) &&
(isConstFalseVal(N1C) ||
isExtendedTrueVal(N1C, N0->getValueType(0), SExt))) {
bool Inverse = (N1C->isNullValue() && Cond == ISD::SETEQ) ||
(!N1C->isNullValue() && Cond == ISD::SETNE);
if (!Inverse)
return TopSetCC;
ISD::CondCode InvCond = ISD::getSetCCInverse(
cast<CondCodeSDNode>(TopSetCC.getOperand(2))->get(),
TopSetCC.getOperand(0).getValueType());
return DAG.getSetCC(dl, VT, TopSetCC.getOperand(0),
TopSetCC.getOperand(1),
InvCond);
}
}
}
// If the LHS is '(and load, const)', the RHS is 0, the test is for
// equality or unsigned, and all 1 bits of the const are in the same
// partial word, see if we can shorten the load.
if (DCI.isBeforeLegalize() &&
!ISD::isSignedIntSetCC(Cond) &&
N0.getOpcode() == ISD::AND && C1 == 0 &&
N0.getNode()->hasOneUse() &&
isa<LoadSDNode>(N0.getOperand(0)) &&
N0.getOperand(0).getNode()->hasOneUse() &&
isa<ConstantSDNode>(N0.getOperand(1))) {
LoadSDNode *Lod = cast<LoadSDNode>(N0.getOperand(0));
APInt bestMask;
unsigned bestWidth = 0, bestOffset = 0;
if (Lod->isSimple() && Lod->isUnindexed()) {
unsigned origWidth = N0.getValueSizeInBits();
unsigned maskWidth = origWidth;
// We can narrow (e.g.) 16-bit extending loads on 32-bit target to
// 8 bits, but have to be careful...
if (Lod->getExtensionType() != ISD::NON_EXTLOAD)
origWidth = Lod->getMemoryVT().getSizeInBits();
const APInt &Mask = N0.getConstantOperandAPInt(1);
for (unsigned width = origWidth / 2; width>=8; width /= 2) {
APInt newMask = APInt::getLowBitsSet(maskWidth, width);
for (unsigned offset=0; offset<origWidth/width; offset++) {
if (Mask.isSubsetOf(newMask)) {
if (Layout.isLittleEndian())
bestOffset = (uint64_t)offset * (width/8);
else
bestOffset = (origWidth/width - offset - 1) * (width/8);
bestMask = Mask.lshr(offset * (width/8) * 8);
bestWidth = width;
break;
}
newMask <<= width;
}
}
}
if (bestWidth) {
EVT newVT = EVT::getIntegerVT(*DAG.getContext(), bestWidth);
if (newVT.isRound() &&
shouldReduceLoadWidth(Lod, ISD::NON_EXTLOAD, newVT)) {
SDValue Ptr = Lod->getBasePtr();
if (bestOffset != 0)
Ptr = DAG.getMemBasePlusOffset(Ptr, bestOffset, dl);
unsigned NewAlign = MinAlign(Lod->getAlignment(), bestOffset);
SDValue NewLoad = DAG.getLoad(
newVT, dl, Lod->getChain(), Ptr,
Lod->getPointerInfo().getWithOffset(bestOffset), NewAlign);
return DAG.getSetCC(dl, VT,
DAG.getNode(ISD::AND, dl, newVT, NewLoad,
DAG.getConstant(bestMask.trunc(bestWidth),
dl, newVT)),
DAG.getConstant(0LL, dl, newVT), Cond);
}
}
}
// If the LHS is a ZERO_EXTEND, perform the comparison on the input.
if (N0.getOpcode() == ISD::ZERO_EXTEND) {
unsigned InSize = N0.getOperand(0).getValueSizeInBits();
// If the comparison constant has bits in the upper part, the
// zero-extended value could never match.
if (C1.intersects(APInt::getHighBitsSet(C1.getBitWidth(),
C1.getBitWidth() - InSize))) {
switch (Cond) {
case ISD::SETUGT:
case ISD::SETUGE:
case ISD::SETEQ:
return DAG.getConstant(0, dl, VT);
case ISD::SETULT:
case ISD::SETULE:
case ISD::SETNE:
return DAG.getConstant(1, dl, VT);
case ISD::SETGT:
case ISD::SETGE:
// True if the sign bit of C1 is set.
return DAG.getConstant(C1.isNegative(), dl, VT);
case ISD::SETLT:
case ISD::SETLE:
// True if the sign bit of C1 isn't set.
return DAG.getConstant(C1.isNonNegative(), dl, VT);
default:
break;
}
}
// Otherwise, we can perform the comparison with the low bits.
switch (Cond) {
case ISD::SETEQ:
case ISD::SETNE:
case ISD::SETUGT:
case ISD::SETUGE:
case ISD::SETULT:
case ISD::SETULE: {
EVT newVT = N0.getOperand(0).getValueType();
if (DCI.isBeforeLegalizeOps() ||
(isOperationLegal(ISD::SETCC, newVT) &&
isCondCodeLegal(Cond, newVT.getSimpleVT()))) {
EVT NewSetCCVT = getSetCCResultType(Layout, *DAG.getContext(), newVT);
SDValue NewConst = DAG.getConstant(C1.trunc(InSize), dl, newVT);
SDValue NewSetCC = DAG.getSetCC(dl, NewSetCCVT, N0.getOperand(0),
NewConst, Cond);
return DAG.getBoolExtOrTrunc(NewSetCC, dl, VT, N0.getValueType());
}
break;
}
default:
break; // todo, be more careful with signed comparisons
}
} else if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG &&
(Cond == ISD::SETEQ || Cond == ISD::SETNE)) {
EVT ExtSrcTy = cast<VTSDNode>(N0.getOperand(1))->getVT();
unsigned ExtSrcTyBits = ExtSrcTy.getSizeInBits();
EVT ExtDstTy = N0.getValueType();
unsigned ExtDstTyBits = ExtDstTy.getSizeInBits();
// If the constant doesn't fit into the number of bits for the source of
// the sign extension, it is impossible for both sides to be equal.
if (C1.getMinSignedBits() > ExtSrcTyBits)
return DAG.getConstant(Cond == ISD::SETNE, dl, VT);
SDValue ZextOp;
EVT Op0Ty = N0.getOperand(0).getValueType();
if (Op0Ty == ExtSrcTy) {
ZextOp = N0.getOperand(0);
} else {
APInt Imm = APInt::getLowBitsSet(ExtDstTyBits, ExtSrcTyBits);
ZextOp = DAG.getNode(ISD::AND, dl, Op0Ty, N0.getOperand(0),
DAG.getConstant(Imm, dl, Op0Ty));
}
if (!DCI.isCalledByLegalizer())
DCI.AddToWorklist(ZextOp.getNode());
// Otherwise, make this a use of a zext.
return DAG.getSetCC(dl, VT, ZextOp,
DAG.getConstant(C1 & APInt::getLowBitsSet(
ExtDstTyBits,
ExtSrcTyBits),
dl, ExtDstTy),
Cond);
} else if ((N1C->isNullValue() || N1C->isOne()) &&
(Cond == ISD::SETEQ || Cond == ISD::SETNE)) {
// SETCC (SETCC), [0|1], [EQ|NE] -> SETCC
if (N0.getOpcode() == ISD::SETCC &&
isTypeLegal(VT) && VT.bitsLE(N0.getValueType()) &&
(N0.getValueType() == MVT::i1 ||
getBooleanContents(N0.getOperand(0).getValueType()) ==
ZeroOrOneBooleanContent)) {
bool TrueWhenTrue = (Cond == ISD::SETEQ) ^ (!N1C->isOne());
if (TrueWhenTrue)
return DAG.getNode(ISD::TRUNCATE, dl, VT, N0);
// Invert the condition.
ISD::CondCode CC = cast<CondCodeSDNode>(N0.getOperand(2))->get();
CC = ISD::getSetCCInverse(CC, N0.getOperand(0).getValueType());
if (DCI.isBeforeLegalizeOps() ||
isCondCodeLegal(CC, N0.getOperand(0).getSimpleValueType()))
return DAG.getSetCC(dl, VT, N0.getOperand(0), N0.getOperand(1), CC);
}
if ((N0.getOpcode() == ISD::XOR ||
(N0.getOpcode() == ISD::AND &&
N0.getOperand(0).getOpcode() == ISD::XOR &&
N0.getOperand(1) == N0.getOperand(0).getOperand(1))) &&
isa<ConstantSDNode>(N0.getOperand(1)) &&
cast<ConstantSDNode>(N0.getOperand(1))->isOne()) {
// If this is (X^1) == 0/1, swap the RHS and eliminate the xor. We
// can only do this if the top bits are known zero.
unsigned BitWidth = N0.getValueSizeInBits();
if (DAG.MaskedValueIsZero(N0,
APInt::getHighBitsSet(BitWidth,
BitWidth-1))) {
// Okay, get the un-inverted input value.
SDValue Val;
if (N0.getOpcode() == ISD::XOR) {
Val = N0.getOperand(0);
} else {
assert(N0.getOpcode() == ISD::AND &&
N0.getOperand(0).getOpcode() == ISD::XOR);
// ((X^1)&1)^1 -> X & 1
Val = DAG.getNode(ISD::AND, dl, N0.getValueType(),
N0.getOperand(0).getOperand(0),
N0.getOperand(1));
}
return DAG.getSetCC(dl, VT, Val, N1,
Cond == ISD::SETEQ ? ISD::SETNE : ISD::SETEQ);
}
} else if (N1C->isOne()) {
SDValue Op0 = N0;
if (Op0.getOpcode() == ISD::TRUNCATE)
Op0 = Op0.getOperand(0);
if ((Op0.getOpcode() == ISD::XOR) &&
Op0.getOperand(0).getOpcode() == ISD::SETCC &&
Op0.getOperand(1).getOpcode() == ISD::SETCC) {
SDValue XorLHS = Op0.getOperand(0);
SDValue XorRHS = Op0.getOperand(1);
// Ensure that the input setccs return an i1 type or 0/1 value.
if (Op0.getValueType() == MVT::i1 ||
(getBooleanContents(XorLHS.getOperand(0).getValueType()) ==
ZeroOrOneBooleanContent &&
getBooleanContents(XorRHS.getOperand(0).getValueType()) ==
ZeroOrOneBooleanContent)) {
// (xor (setcc), (setcc)) == / != 1 -> (setcc) != / == (setcc)
Cond = (Cond == ISD::SETEQ) ? ISD::SETNE : ISD::SETEQ;
return DAG.getSetCC(dl, VT, XorLHS, XorRHS, Cond);
}
}
if (Op0.getOpcode() == ISD::AND &&
isa<ConstantSDNode>(Op0.getOperand(1)) &&
cast<ConstantSDNode>(Op0.getOperand(1))->isOne()) {
// If this is (X&1) == / != 1, normalize it to (X&1) != / == 0.
if (Op0.getValueType().bitsGT(VT))
Op0 = DAG.getNode(ISD::AND, dl, VT,
DAG.getNode(ISD::TRUNCATE, dl, VT, Op0.getOperand(0)),
DAG.getConstant(1, dl, VT));
else if (Op0.getValueType().bitsLT(VT))
Op0 = DAG.getNode(ISD::AND, dl, VT,
DAG.getNode(ISD::ANY_EXTEND, dl, VT, Op0.getOperand(0)),
DAG.getConstant(1, dl, VT));
return DAG.getSetCC(dl, VT, Op0,
DAG.getConstant(0, dl, Op0.getValueType()),
Cond == ISD::SETEQ ? ISD::SETNE : ISD::SETEQ);
}
if (Op0.getOpcode() == ISD::AssertZext &&
cast<VTSDNode>(Op0.getOperand(1))->getVT() == MVT::i1)
return DAG.getSetCC(dl, VT, Op0,
DAG.getConstant(0, dl, Op0.getValueType()),
Cond == ISD::SETEQ ? ISD::SETNE : ISD::SETEQ);
}
}
// Given:
// icmp eq/ne (urem %x, %y), 0
// Iff %x has 0 or 1 bits set, and %y has at least 2 bits set, omit 'urem':
// icmp eq/ne %x, 0
if (N0.getOpcode() == ISD::UREM && N1C->isNullValue() &&
(Cond == ISD::SETEQ || Cond == ISD::SETNE)) {
KnownBits XKnown = DAG.computeKnownBits(N0.getOperand(0));
KnownBits YKnown = DAG.computeKnownBits(N0.getOperand(1));
if (XKnown.countMaxPopulation() == 1 && YKnown.countMinPopulation() >= 2)
return DAG.getSetCC(dl, VT, N0.getOperand(0), N1, Cond);
}
if (SDValue V =
optimizeSetCCOfSignedTruncationCheck(VT, N0, N1, Cond, DCI, dl))
return V;
}
// These simplifications apply to splat vectors as well.
// TODO: Handle more splat vector cases.
if (auto *N1C = isConstOrConstSplat(N1)) {
const APInt &C1 = N1C->getAPIntValue();
APInt MinVal, MaxVal;
unsigned OperandBitSize = N1C->getValueType(0).getScalarSizeInBits();
if (ISD::isSignedIntSetCC(Cond)) {
MinVal = APInt::getSignedMinValue(OperandBitSize);
MaxVal = APInt::getSignedMaxValue(OperandBitSize);
} else {
MinVal = APInt::getMinValue(OperandBitSize);
MaxVal = APInt::getMaxValue(OperandBitSize);
}
// Canonicalize GE/LE comparisons to use GT/LT comparisons.
if (Cond == ISD::SETGE || Cond == ISD::SETUGE) {
// X >= MIN --> true
if (C1 == MinVal)
return DAG.getBoolConstant(true, dl, VT, OpVT);
if (!VT.isVector()) { // TODO: Support this for vectors.
// X >= C0 --> X > (C0 - 1)
APInt C = C1 - 1;
ISD::CondCode NewCC = (Cond == ISD::SETGE) ? ISD::SETGT : ISD::SETUGT;
if ((DCI.isBeforeLegalizeOps() ||
isCondCodeLegal(NewCC, VT.getSimpleVT())) &&
(!N1C->isOpaque() || (C.getBitWidth() <= 64 &&
isLegalICmpImmediate(C.getSExtValue())))) {
return DAG.getSetCC(dl, VT, N0,
DAG.getConstant(C, dl, N1.getValueType()),
NewCC);
}
}
}
if (Cond == ISD::SETLE || Cond == ISD::SETULE) {
// X <= MAX --> true
if (C1 == MaxVal)
return DAG.getBoolConstant(true, dl, VT, OpVT);
// X <= C0 --> X < (C0 + 1)
if (!VT.isVector()) { // TODO: Support this for vectors.
APInt C = C1 + 1;
ISD::CondCode NewCC = (Cond == ISD::SETLE) ? ISD::SETLT : ISD::SETULT;
if ((DCI.isBeforeLegalizeOps() ||
isCondCodeLegal(NewCC, VT.getSimpleVT())) &&
(!N1C->isOpaque() || (C.getBitWidth() <= 64 &&
isLegalICmpImmediate(C.getSExtValue())))) {
return DAG.getSetCC(dl, VT, N0,
DAG.getConstant(C, dl, N1.getValueType()),
NewCC);
}
}
}
if (Cond == ISD::SETLT || Cond == ISD::SETULT) {
if (C1 == MinVal)
return DAG.getBoolConstant(false, dl, VT, OpVT); // X < MIN --> false
// TODO: Support this for vectors after legalize ops.
if (!VT.isVector() || DCI.isBeforeLegalizeOps()) {
// Canonicalize setlt X, Max --> setne X, Max
if (C1 == MaxVal)
return DAG.getSetCC(dl, VT, N0, N1, ISD::SETNE);
// If we have setult X, 1, turn it into seteq X, 0
if (C1 == MinVal+1)
return DAG.getSetCC(dl, VT, N0,
DAG.getConstant(MinVal, dl, N0.getValueType()),
ISD::SETEQ);
}
}
if (Cond == ISD::SETGT || Cond == ISD::SETUGT) {
if (C1 == MaxVal)
return DAG.getBoolConstant(false, dl, VT, OpVT); // X > MAX --> false
// TODO: Support this for vectors after legalize ops.
if (!VT.isVector() || DCI.isBeforeLegalizeOps()) {
// Canonicalize setgt X, Min --> setne X, Min
if (C1 == MinVal)
return DAG.getSetCC(dl, VT, N0, N1, ISD::SETNE);
// If we have setugt X, Max-1, turn it into seteq X, Max
if (C1 == MaxVal-1)
return DAG.getSetCC(dl, VT, N0,
DAG.getConstant(MaxVal, dl, N0.getValueType()),
ISD::SETEQ);
}
}
if (Cond == ISD::SETEQ || Cond == ISD::SETNE) {
// (X & (C l>>/<< Y)) ==/!= 0 --> ((X <</l>> Y) & C) ==/!= 0
if (C1.isNullValue())
if (SDValue CC = optimizeSetCCByHoistingAndByConstFromLogicalShift(
VT, N0, N1, Cond, DCI, dl))
return CC;
}
// If we have "setcc X, C0", check to see if we can shrink the immediate
// by changing cc.
// TODO: Support this for vectors after legalize ops.
if (!VT.isVector() || DCI.isBeforeLegalizeOps()) {
// SETUGT X, SINTMAX -> SETLT X, 0
if (Cond == ISD::SETUGT &&
C1 == APInt::getSignedMaxValue(OperandBitSize))
return DAG.getSetCC(dl, VT, N0,
DAG.getConstant(0, dl, N1.getValueType()),
ISD::SETLT);
// SETULT X, SINTMIN -> SETGT X, -1
if (Cond == ISD::SETULT &&
C1 == APInt::getSignedMinValue(OperandBitSize)) {
SDValue ConstMinusOne =
DAG.getConstant(APInt::getAllOnesValue(OperandBitSize), dl,
N1.getValueType());
return DAG.getSetCC(dl, VT, N0, ConstMinusOne, ISD::SETGT);
}
}
}
// Back to non-vector simplifications.
// TODO: Can we do these for vector splats?
if (auto *N1C = dyn_cast<ConstantSDNode>(N1.getNode())) {
const TargetLowering &TLI = DAG.getTargetLoweringInfo();
const APInt &C1 = N1C->getAPIntValue();
EVT ShValTy = N0.getValueType();
// Fold bit comparisons when we can.
if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
(VT == ShValTy || (isTypeLegal(VT) && VT.bitsLE(ShValTy))) &&
N0.getOpcode() == ISD::AND) {
if (auto *AndRHS = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
EVT ShiftTy =
getShiftAmountTy(ShValTy, Layout, !DCI.isBeforeLegalize());
if (Cond == ISD::SETNE && C1 == 0) {// (X & 8) != 0 --> (X & 8) >> 3
// Perform the xform if the AND RHS is a single bit.
unsigned ShCt = AndRHS->getAPIntValue().logBase2();
if (AndRHS->getAPIntValue().isPowerOf2() &&
!TLI.shouldAvoidTransformToShift(ShValTy, ShCt)) {
return DAG.getNode(ISD::TRUNCATE, dl, VT,
DAG.getNode(ISD::SRL, dl, ShValTy, N0,
DAG.getConstant(ShCt, dl, ShiftTy)));
}
} else if (Cond == ISD::SETEQ && C1 == AndRHS->getAPIntValue()) {
// (X & 8) == 8 --> (X & 8) >> 3
// Perform the xform if C1 is a single bit.
unsigned ShCt = C1.logBase2();
if (C1.isPowerOf2() &&
!TLI.shouldAvoidTransformToShift(ShValTy, ShCt)) {
return DAG.getNode(ISD::TRUNCATE, dl, VT,
DAG.getNode(ISD::SRL, dl, ShValTy, N0,
DAG.getConstant(ShCt, dl, ShiftTy)));
}
}
}
}
if (C1.getMinSignedBits() <= 64 &&
!isLegalICmpImmediate(C1.getSExtValue())) {
EVT ShiftTy = getShiftAmountTy(ShValTy, Layout, !DCI.isBeforeLegalize());
// (X & -256) == 256 -> (X >> 8) == 1
if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
N0.getOpcode() == ISD::AND && N0.hasOneUse()) {
if (auto *AndRHS = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
const APInt &AndRHSC = AndRHS->getAPIntValue();
if ((-AndRHSC).isPowerOf2() && (AndRHSC & C1) == C1) {
unsigned ShiftBits = AndRHSC.countTrailingZeros();
if (!TLI.shouldAvoidTransformToShift(ShValTy, ShiftBits)) {
SDValue Shift =
DAG.getNode(ISD::SRL, dl, ShValTy, N0.getOperand(0),
DAG.getConstant(ShiftBits, dl, ShiftTy));
SDValue CmpRHS = DAG.getConstant(C1.lshr(ShiftBits), dl, ShValTy);
return DAG.getSetCC(dl, VT, Shift, CmpRHS, Cond);
}
}
}
} else if (Cond == ISD::SETULT || Cond == ISD::SETUGE ||
Cond == ISD::SETULE || Cond == ISD::SETUGT) {
bool AdjOne = (Cond == ISD::SETULE || Cond == ISD::SETUGT);
// X < 0x100000000 -> (X >> 32) < 1
// X >= 0x100000000 -> (X >> 32) >= 1
// X <= 0x0ffffffff -> (X >> 32) < 1
// X > 0x0ffffffff -> (X >> 32) >= 1
unsigned ShiftBits;
APInt NewC = C1;
ISD::CondCode NewCond = Cond;
if (AdjOne) {
ShiftBits = C1.countTrailingOnes();
NewC = NewC + 1;
NewCond = (Cond == ISD::SETULE) ? ISD::SETULT : ISD::SETUGE;
} else {
ShiftBits = C1.countTrailingZeros();
}
NewC.lshrInPlace(ShiftBits);
if (ShiftBits && NewC.getMinSignedBits() <= 64 &&
isLegalICmpImmediate(NewC.getSExtValue()) &&
!TLI.shouldAvoidTransformToShift(ShValTy, ShiftBits)) {
SDValue Shift = DAG.getNode(ISD::SRL, dl, ShValTy, N0,
DAG.getConstant(ShiftBits, dl, ShiftTy));
SDValue CmpRHS = DAG.getConstant(NewC, dl, ShValTy);
return DAG.getSetCC(dl, VT, Shift, CmpRHS, NewCond);
}
}
}
}
if (!isa<ConstantFPSDNode>(N0) && isa<ConstantFPSDNode>(N1)) {
auto *CFP = cast<ConstantFPSDNode>(N1);
assert(!CFP->getValueAPF().isNaN() && "Unexpected NaN value");
// Otherwise, we know the RHS is not a NaN. Simplify the node to drop the
// constant if knowing that the operand is non-nan is enough. We prefer to
// have SETO(x,x) instead of SETO(x, 0.0) because this avoids having to
// materialize 0.0.
if (Cond == ISD::SETO || Cond == ISD::SETUO)
return DAG.getSetCC(dl, VT, N0, N0, Cond);
// setcc (fneg x), C -> setcc swap(pred) x, -C
if (N0.getOpcode() == ISD::FNEG) {
ISD::CondCode SwapCond = ISD::getSetCCSwappedOperands(Cond);
if (DCI.isBeforeLegalizeOps() ||
isCondCodeLegal(SwapCond, N0.getSimpleValueType())) {
SDValue NegN1 = DAG.getNode(ISD::FNEG, dl, N0.getValueType(), N1);
return DAG.getSetCC(dl, VT, N0.getOperand(0), NegN1, SwapCond);
}
}
// If the condition is not legal, see if we can find an equivalent one
// which is legal.
if (!isCondCodeLegal(Cond, N0.getSimpleValueType())) {
// If the comparison was an awkward floating-point == or != and one of
// the comparison operands is infinity or negative infinity, convert the
// condition to a less-awkward <= or >=.
if (CFP->getValueAPF().isInfinity()) {
bool IsNegInf = CFP->getValueAPF().isNegative();
ISD::CondCode NewCond = ISD::SETCC_INVALID;
switch (Cond) {
case ISD::SETOEQ: NewCond = IsNegInf ? ISD::SETOLE : ISD::SETOGE; break;
case ISD::SETUEQ: NewCond = IsNegInf ? ISD::SETULE : ISD::SETUGE; break;
case ISD::SETUNE: NewCond = IsNegInf ? ISD::SETUGT : ISD::SETULT; break;
case ISD::SETONE: NewCond = IsNegInf ? ISD::SETOGT : ISD::SETOLT; break;
default: break;
}
if (NewCond != ISD::SETCC_INVALID &&
isCondCodeLegal(NewCond, N0.getSimpleValueType()))
return DAG.getSetCC(dl, VT, N0, N1, NewCond);
}
}
}
if (N0 == N1) {
// The sext(setcc()) => setcc() optimization relies on the appropriate
// constant being emitted.
assert(!N0.getValueType().isInteger() &&
"Integer types should be handled by FoldSetCC");
bool EqTrue = ISD::isTrueWhenEqual(Cond);
unsigned UOF = ISD::getUnorderedFlavor(Cond);
if (UOF == 2) // FP operators that are undefined on NaNs.
return DAG.getBoolConstant(EqTrue, dl, VT, OpVT);
if (UOF == unsigned(EqTrue))
return DAG.getBoolConstant(EqTrue, dl, VT, OpVT);
// Otherwise, we can't fold it. However, we can simplify it to SETUO/SETO
// if it is not already.
ISD::CondCode NewCond = UOF == 0 ? ISD::SETO : ISD::SETUO;
if (NewCond != Cond &&
(DCI.isBeforeLegalizeOps() ||
isCondCodeLegal(NewCond, N0.getSimpleValueType())))
return DAG.getSetCC(dl, VT, N0, N1, NewCond);
}
if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
N0.getValueType().isInteger()) {
if (N0.getOpcode() == ISD::ADD || N0.getOpcode() == ISD::SUB ||
N0.getOpcode() == ISD::XOR) {
// Simplify (X+Y) == (X+Z) --> Y == Z
if (N0.getOpcode() == N1.getOpcode()) {
if (N0.getOperand(0) == N1.getOperand(0))
return DAG.getSetCC(dl, VT, N0.getOperand(1), N1.getOperand(1), Cond);
if (N0.getOperand(1) == N1.getOperand(1))
return DAG.getSetCC(dl, VT, N0.getOperand(0), N1.getOperand(0), Cond);
if (isCommutativeBinOp(N0.getOpcode())) {
// If X op Y == Y op X, try other combinations.
if (N0.getOperand(0) == N1.getOperand(1))
return DAG.getSetCC(dl, VT, N0.getOperand(1), N1.getOperand(0),
Cond);
if (N0.getOperand(1) == N1.getOperand(0))
return DAG.getSetCC(dl, VT, N0.getOperand(0), N1.getOperand(1),
Cond);
}
}
// If RHS is a legal immediate value for a compare instruction, we need
// to be careful about increasing register pressure needlessly.
bool LegalRHSImm = false;
if (auto *RHSC = dyn_cast<ConstantSDNode>(N1)) {
if (auto *LHSR = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
// Turn (X+C1) == C2 --> X == C2-C1
if (N0.getOpcode() == ISD::ADD && N0.getNode()->hasOneUse()) {
return DAG.getSetCC(dl, VT, N0.getOperand(0),
DAG.getConstant(RHSC->getAPIntValue()-
LHSR->getAPIntValue(),
dl, N0.getValueType()), Cond);
}
// Turn (X^C1) == C2 into X == C1^C2 iff X&~C1 = 0.
if (N0.getOpcode() == ISD::XOR)
// If we know that all of the inverted bits are zero, don't bother
// performing the inversion.
if (DAG.MaskedValueIsZero(N0.getOperand(0), ~LHSR->getAPIntValue()))
return
DAG.getSetCC(dl, VT, N0.getOperand(0),
DAG.getConstant(LHSR->getAPIntValue() ^
RHSC->getAPIntValue(),
dl, N0.getValueType()),
Cond);
}
// Turn (C1-X) == C2 --> X == C1-C2
if (auto *SUBC = dyn_cast<ConstantSDNode>(N0.getOperand(0))) {
if (N0.getOpcode() == ISD::SUB && N0.getNode()->hasOneUse()) {
return
DAG.getSetCC(dl, VT, N0.getOperand(1),
DAG.getConstant(SUBC->getAPIntValue() -
RHSC->getAPIntValue(),
dl, N0.getValueType()),
Cond);
}
}
// Could RHSC fold directly into a compare?
if (RHSC->getValueType(0).getSizeInBits() <= 64)
LegalRHSImm = isLegalICmpImmediate(RHSC->getSExtValue());
}
// (X+Y) == X --> Y == 0 and similar folds.
// Don't do this if X is an immediate that can fold into a cmp
// instruction and X+Y has other uses. It could be an induction variable
// chain, and the transform would increase register pressure.
if (!LegalRHSImm || N0.hasOneUse())
if (SDValue V = foldSetCCWithBinOp(VT, N0, N1, Cond, dl, DCI))
return V;
}
if (N1.getOpcode() == ISD::ADD || N1.getOpcode() == ISD::SUB ||
N1.getOpcode() == ISD::XOR)
if (SDValue V = foldSetCCWithBinOp(VT, N1, N0, Cond, dl, DCI))
return V;
if (SDValue V = foldSetCCWithAnd(VT, N0, N1, Cond, dl, DCI))
return V;
}
// Fold remainder of division by a constant.
if ((N0.getOpcode() == ISD::UREM || N0.getOpcode() == ISD::SREM) &&
N0.hasOneUse() && (Cond == ISD::SETEQ || Cond == ISD::SETNE)) {
AttributeList Attr = DAG.getMachineFunction().getFunction().getAttributes();
// When division is cheap or optimizing for minimum size,
// fall through to DIVREM creation by skipping this fold.
if (!isIntDivCheap(VT, Attr) && !Attr.hasFnAttribute(Attribute::MinSize)) {
if (N0.getOpcode() == ISD::UREM) {
if (SDValue Folded = buildUREMEqFold(VT, N0, N1, Cond, DCI, dl))
return Folded;
} else if (N0.getOpcode() == ISD::SREM) {
if (SDValue Folded = buildSREMEqFold(VT, N0, N1, Cond, DCI, dl))
return Folded;
}
}
}
// Fold away ALL boolean setcc's.
if (N0.getValueType().getScalarType() == MVT::i1 && foldBooleans) {
SDValue Temp;
switch (Cond) {
default: llvm_unreachable("Unknown integer setcc!");
case ISD::SETEQ: // X == Y -> ~(X^Y)
Temp = DAG.getNode(ISD::XOR, dl, OpVT, N0, N1);
N0 = DAG.getNOT(dl, Temp, OpVT);
if (!DCI.isCalledByLegalizer())
DCI.AddToWorklist(Temp.getNode());
break;
case ISD::SETNE: // X != Y --> (X^Y)
N0 = DAG.getNode(ISD::XOR, dl, OpVT, N0, N1);
break;
case ISD::SETGT: // X >s Y --> X == 0 & Y == 1 --> ~X & Y
case ISD::SETULT: // X <u Y --> X == 0 & Y == 1 --> ~X & Y
Temp = DAG.getNOT(dl, N0, OpVT);
N0 = DAG.getNode(ISD::AND, dl, OpVT, N1, Temp);
if (!DCI.isCalledByLegalizer())
DCI.AddToWorklist(Temp.getNode());
break;
case ISD::SETLT: // X <s Y --> X == 1 & Y == 0 --> ~Y & X
case ISD::SETUGT: // X >u Y --> X == 1 & Y == 0 --> ~Y & X
Temp = DAG.getNOT(dl, N1, OpVT);
N0 = DAG.getNode(ISD::AND, dl, OpVT, N0, Temp);
if (!DCI.isCalledByLegalizer())
DCI.AddToWorklist(Temp.getNode());
break;
case ISD::SETULE: // X <=u Y --> X == 0 | Y == 1 --> ~X | Y
case ISD::SETGE: // X >=s Y --> X == 0 | Y == 1 --> ~X | Y
Temp = DAG.getNOT(dl, N0, OpVT);
N0 = DAG.getNode(ISD::OR, dl, OpVT, N1, Temp);
if (!DCI.isCalledByLegalizer())
DCI.AddToWorklist(Temp.getNode());
break;
case ISD::SETUGE: // X >=u Y --> X == 1 | Y == 0 --> ~Y | X
case ISD::SETLE: // X <=s Y --> X == 1 | Y == 0 --> ~Y | X
Temp = DAG.getNOT(dl, N1, OpVT);
N0 = DAG.getNode(ISD::OR, dl, OpVT, N0, Temp);
break;
}
if (VT.getScalarType() != MVT::i1) {
if (!DCI.isCalledByLegalizer())
DCI.AddToWorklist(N0.getNode());
// FIXME: If running after legalize, we probably can't do this.
ISD::NodeType ExtendCode = getExtendForContent(getBooleanContents(OpVT));
N0 = DAG.getNode(ExtendCode, dl, VT, N0);
}
return N0;
}
// Could not fold it.
return SDValue();
}
/// Returns true (and the GlobalValue and the offset) if the node is a
/// GlobalAddress + offset.
bool TargetLowering::isGAPlusOffset(SDNode *WN, const GlobalValue *&GA,
int64_t &Offset) const {
SDNode *N = unwrapAddress(SDValue(WN, 0)).getNode();
if (auto *GASD = dyn_cast<GlobalAddressSDNode>(N)) {
GA = GASD->getGlobal();
Offset += GASD->getOffset();
return true;
}
if (N->getOpcode() == ISD::ADD) {
SDValue N1 = N->getOperand(0);
SDValue N2 = N->getOperand(1);
if (isGAPlusOffset(N1.getNode(), GA, Offset)) {
if (auto *V = dyn_cast<ConstantSDNode>(N2)) {
Offset += V->getSExtValue();
return true;
}
} else if (isGAPlusOffset(N2.getNode(), GA, Offset)) {
if (auto *V = dyn_cast<ConstantSDNode>(N1)) {
Offset += V->getSExtValue();
return true;
}
}
}
return false;
}
SDValue TargetLowering::PerformDAGCombine(SDNode *N,
DAGCombinerInfo &DCI) const {
// Default implementation: no optimization.
return SDValue();
}
//===----------------------------------------------------------------------===//
// Inline Assembler Implementation Methods
//===----------------------------------------------------------------------===//
TargetLowering::ConstraintType
TargetLowering::getConstraintType(StringRef Constraint) const {
unsigned S = Constraint.size();
if (S == 1) {
switch (Constraint[0]) {
default: break;
case 'r':
return C_RegisterClass;
case 'm': // memory
case 'o': // offsetable
case 'V': // not offsetable
return C_Memory;
case 'n': // Simple Integer
case 'E': // Floating Point Constant
case 'F': // Floating Point Constant
return C_Immediate;
case 'i': // Simple Integer or Relocatable Constant
case 's': // Relocatable Constant
case 'p': // Address.
case 'X': // Allow ANY value.
case 'I': // Target registers.
case 'J':
case 'K':
case 'L':
case 'M':
case 'N':
case 'O':
case 'P':
case '<':
case '>':
return C_Other;
}
}
if (S > 1 && Constraint[0] == '{' && Constraint[S - 1] == '}') {
if (S == 8 && Constraint.substr(1, 6) == "memory") // "{memory}"
return C_Memory;
return C_Register;
}
return C_Unknown;
}
/// Try to replace an X constraint, which matches anything, with another that
/// has more specific requirements based on the type of the corresponding
/// operand.
const char *TargetLowering::LowerXConstraint(EVT ConstraintVT) const {
if (ConstraintVT.isInteger())
return "r";
if (ConstraintVT.isFloatingPoint())
return "f"; // works for many targets
return nullptr;
}
SDValue TargetLowering::LowerAsmOutputForConstraint(
SDValue &Chain, SDValue &Flag, SDLoc DL, const AsmOperandInfo &OpInfo,
SelectionDAG &DAG) const {
return SDValue();
}
/// Lower the specified operand into the Ops vector.
/// If it is invalid, don't add anything to Ops.
void TargetLowering::LowerAsmOperandForConstraint(SDValue Op,
std::string &Constraint,
std::vector<SDValue> &Ops,
SelectionDAG &DAG) const {
if (Constraint.length() > 1) return;
char ConstraintLetter = Constraint[0];
switch (ConstraintLetter) {
default: break;
case 'X': // Allows any operand; labels (basic block) use this.
if (Op.getOpcode() == ISD::BasicBlock ||
Op.getOpcode() == ISD::TargetBlockAddress) {
Ops.push_back(Op);
return;
}
LLVM_FALLTHROUGH;
case 'i': // Simple Integer or Relocatable Constant
case 'n': // Simple Integer
case 's': { // Relocatable Constant
GlobalAddressSDNode *GA;
ConstantSDNode *C;
BlockAddressSDNode *BA;
uint64_t Offset = 0;
// Match (GA) or (C) or (GA+C) or (GA-C) or ((GA+C)+C) or (((GA+C)+C)+C),
// etc., since getelementpointer is variadic. We can't use
// SelectionDAG::FoldSymbolOffset because it expects the GA to be accessible
// while in this case the GA may be furthest from the root node which is
// likely an ISD::ADD.
while (1) {
if ((GA = dyn_cast<GlobalAddressSDNode>(Op)) && ConstraintLetter != 'n') {
Ops.push_back(DAG.getTargetGlobalAddress(GA->getGlobal(), SDLoc(Op),
GA->getValueType(0),
Offset + GA->getOffset()));
return;
} else if ((C = dyn_cast<ConstantSDNode>(Op)) &&
ConstraintLetter != 's') {
// gcc prints these as sign extended. Sign extend value to 64 bits
// now; without this it would get ZExt'd later in
// ScheduleDAGSDNodes::EmitNode, which is very generic.
bool IsBool = C->getConstantIntValue()->getBitWidth() == 1;
BooleanContent BCont = getBooleanContents(MVT::i64);
ISD::NodeType ExtOpc = IsBool ? getExtendForContent(BCont)
: ISD::SIGN_EXTEND;
int64_t ExtVal = ExtOpc == ISD::ZERO_EXTEND ? C->getZExtValue()
: C->getSExtValue();
Ops.push_back(DAG.getTargetConstant(Offset + ExtVal,
SDLoc(C), MVT::i64));
return;
} else if ((BA = dyn_cast<BlockAddressSDNode>(Op)) &&
ConstraintLetter != 'n') {
Ops.push_back(DAG.getTargetBlockAddress(
BA->getBlockAddress(), BA->getValueType(0),
Offset + BA->getOffset(), BA->getTargetFlags()));
return;
} else {
const unsigned OpCode = Op.getOpcode();
if (OpCode == ISD::ADD || OpCode == ISD::SUB) {
if ((C = dyn_cast<ConstantSDNode>(Op.getOperand(0))))
Op = Op.getOperand(1);
// Subtraction is not commutative.
else if (OpCode == ISD::ADD &&
(C = dyn_cast<ConstantSDNode>(Op.getOperand(1))))
Op = Op.getOperand(0);
else
return;
Offset += (OpCode == ISD::ADD ? 1 : -1) * C->getSExtValue();
continue;
}
}
return;
}
break;
}
}
}
std::pair<unsigned, const TargetRegisterClass *>
TargetLowering::getRegForInlineAsmConstraint(const TargetRegisterInfo *RI,
StringRef Constraint,
MVT VT) const {
if (Constraint.empty() || Constraint[0] != '{')
return std::make_pair(0u, static_cast<TargetRegisterClass *>(nullptr));
assert(*(Constraint.end() - 1) == '}' && "Not a brace enclosed constraint?");
// Remove the braces from around the name.
StringRef RegName(Constraint.data() + 1, Constraint.size() - 2);
std::pair<unsigned, const TargetRegisterClass *> R =
std::make_pair(0u, static_cast<const TargetRegisterClass *>(nullptr));
// Figure out which register class contains this reg.
for (const TargetRegisterClass *RC : RI->regclasses()) {
// If none of the value types for this register class are valid, we
// can't use it. For example, 64-bit reg classes on 32-bit targets.
if (!isLegalRC(*RI, *RC))
continue;
for (TargetRegisterClass::iterator I = RC->begin(), E = RC->end();
I != E; ++I) {
if (RegName.equals_lower(RI->getRegAsmName(*I))) {
std::pair<unsigned, const TargetRegisterClass *> S =
std::make_pair(*I, RC);
// If this register class has the requested value type, return it,
// otherwise keep searching and return the first class found
// if no other is found which explicitly has the requested type.
if (RI->isTypeLegalForClass(*RC, VT))
return S;
if (!R.second)
R = S;
}
}
}
return R;
}
//===----------------------------------------------------------------------===//
// Constraint Selection.
/// Return true of this is an input operand that is a matching constraint like
/// "4".
bool TargetLowering::AsmOperandInfo::isMatchingInputConstraint() const {
assert(!ConstraintCode.empty() && "No known constraint!");
return isdigit(static_cast<unsigned char>(ConstraintCode[0]));
}
/// If this is an input matching constraint, this method returns the output
/// operand it matches.
unsigned TargetLowering::AsmOperandInfo::getMatchedOperand() const {
assert(!ConstraintCode.empty() && "No known constraint!");
return atoi(ConstraintCode.c_str());
}
/// Split up the constraint string from the inline assembly value into the
/// specific constraints and their prefixes, and also tie in the associated
/// operand values.
/// If this returns an empty vector, and if the constraint string itself
/// isn't empty, there was an error parsing.
TargetLowering::AsmOperandInfoVector
TargetLowering::ParseConstraints(const DataLayout &DL,
const TargetRegisterInfo *TRI,
const CallBase &Call) const {
/// Information about all of the constraints.
AsmOperandInfoVector ConstraintOperands;
const InlineAsm *IA = cast<InlineAsm>(Call.getCalledOperand());
unsigned maCount = 0; // Largest number of multiple alternative constraints.
// Do a prepass over the constraints, canonicalizing them, and building up the
// ConstraintOperands list.
unsigned ArgNo = 0; // ArgNo - The argument of the CallInst.
unsigned ResNo = 0; // ResNo - The result number of the next output.
for (InlineAsm::ConstraintInfo &CI : IA->ParseConstraints()) {
ConstraintOperands.emplace_back(std::move(CI));
AsmOperandInfo &OpInfo = ConstraintOperands.back();
// Update multiple alternative constraint count.
if (OpInfo.multipleAlternatives.size() > maCount)
maCount = OpInfo.multipleAlternatives.size();
OpInfo.ConstraintVT = MVT::Other;
// Compute the value type for each operand.
switch (OpInfo.Type) {
case InlineAsm::isOutput:
// Indirect outputs just consume an argument.
if (OpInfo.isIndirect) {
OpInfo.CallOperandVal = Call.getArgOperand(ArgNo++);
break;
}
// The return value of the call is this value. As such, there is no
// corresponding argument.
assert(!Call.getType()->isVoidTy() && "Bad inline asm!");
if (StructType *STy = dyn_cast<StructType>(Call.getType())) {
OpInfo.ConstraintVT =
getSimpleValueType(DL, STy->getElementType(ResNo));
} else {
assert(ResNo == 0 && "Asm only has one result!");
OpInfo.ConstraintVT = getSimpleValueType(DL, Call.getType());
}
++ResNo;
break;
case InlineAsm::isInput:
OpInfo.CallOperandVal = Call.getArgOperand(ArgNo++);
break;
case InlineAsm::isClobber:
// Nothing to do.
break;
}
if (OpInfo.CallOperandVal) {
llvm::Type *OpTy = OpInfo.CallOperandVal->getType();
if (OpInfo.isIndirect) {
llvm::PointerType *PtrTy = dyn_cast<PointerType>(OpTy);
if (!PtrTy)
report_fatal_error("Indirect operand for inline asm not a pointer!");
OpTy = PtrTy->getElementType();
}
// Look for vector wrapped in a struct. e.g. { <16 x i8> }.
if (StructType *STy = dyn_cast<StructType>(OpTy))
if (STy->getNumElements() == 1)
OpTy = STy->getElementType(0);
// If OpTy is not a single value, it may be a struct/union that we
// can tile with integers.
if (!OpTy->isSingleValueType() && OpTy->isSized()) {
unsigned BitSize = DL.getTypeSizeInBits(OpTy);
switch (BitSize) {
default: break;
case 1:
case 8:
case 16:
case 32:
case 64:
case 128:
OpInfo.ConstraintVT =
MVT::getVT(IntegerType::get(OpTy->getContext(), BitSize), true);
break;
}
} else if (PointerType *PT = dyn_cast<PointerType>(OpTy)) {
unsigned PtrSize = DL.getPointerSizeInBits(PT->getAddressSpace());
OpInfo.ConstraintVT = MVT::getIntegerVT(PtrSize);
} else {
OpInfo.ConstraintVT = MVT::getVT(OpTy, true);
}
}
}
// If we have multiple alternative constraints, select the best alternative.
if (!ConstraintOperands.empty()) {
if (maCount) {
unsigned bestMAIndex = 0;
int bestWeight = -1;
// weight: -1 = invalid match, and 0 = so-so match to 5 = good match.
int weight = -1;
unsigned maIndex;
// Compute the sums of the weights for each alternative, keeping track
// of the best (highest weight) one so far.
for (maIndex = 0; maIndex < maCount; ++maIndex) {
int weightSum = 0;
for (unsigned cIndex = 0, eIndex = ConstraintOperands.size();
cIndex != eIndex; ++cIndex) {
AsmOperandInfo &OpInfo = ConstraintOperands[cIndex];
if (OpInfo.Type == InlineAsm::isClobber)
continue;
// If this is an output operand with a matching input operand,
// look up the matching input. If their types mismatch, e.g. one
// is an integer, the other is floating point, or their sizes are
// different, flag it as an maCantMatch.
if (OpInfo.hasMatchingInput()) {
AsmOperandInfo &Input = ConstraintOperands[OpInfo.MatchingInput];
if (OpInfo.ConstraintVT != Input.ConstraintVT) {
if ((OpInfo.ConstraintVT.isInteger() !=
Input.ConstraintVT.isInteger()) ||
(OpInfo.ConstraintVT.getSizeInBits() !=
Input.ConstraintVT.getSizeInBits())) {
weightSum = -1; // Can't match.
break;
}
}
}
weight = getMultipleConstraintMatchWeight(OpInfo, maIndex);
if (weight == -1) {
weightSum = -1;
break;
}
weightSum += weight;
}
// Update best.
if (weightSum > bestWeight) {
bestWeight = weightSum;
bestMAIndex = maIndex;
}
}
// Now select chosen alternative in each constraint.
for (unsigned cIndex = 0, eIndex = ConstraintOperands.size();
cIndex != eIndex; ++cIndex) {
AsmOperandInfo &cInfo = ConstraintOperands[cIndex];
if (cInfo.Type == InlineAsm::isClobber)
continue;
cInfo.selectAlternative(bestMAIndex);
}
}
}
// Check and hook up tied operands, choose constraint code to use.
for (unsigned cIndex = 0, eIndex = ConstraintOperands.size();
cIndex != eIndex; ++cIndex) {
AsmOperandInfo &OpInfo = ConstraintOperands[cIndex];
// If this is an output operand with a matching input operand, look up the
// matching input. If their types mismatch, e.g. one is an integer, the
// other is floating point, or their sizes are different, flag it as an
// error.
if (OpInfo.hasMatchingInput()) {
AsmOperandInfo &Input = ConstraintOperands[OpInfo.MatchingInput];
if (OpInfo.ConstraintVT != Input.ConstraintVT) {
std::pair<unsigned, const TargetRegisterClass *> MatchRC =
getRegForInlineAsmConstraint(TRI, OpInfo.ConstraintCode,
OpInfo.ConstraintVT);
std::pair<unsigned, const TargetRegisterClass *> InputRC =
getRegForInlineAsmConstraint(TRI, Input.ConstraintCode,
Input.ConstraintVT);
if ((OpInfo.ConstraintVT.isInteger() !=
Input.ConstraintVT.isInteger()) ||
(MatchRC.second != InputRC.second)) {
report_fatal_error("Unsupported asm: input constraint"
" with a matching output constraint of"
" incompatible type!");
}
}
}
}
return ConstraintOperands;
}
/// Return an integer indicating how general CT is.
static unsigned getConstraintGenerality(TargetLowering::ConstraintType CT) {
switch (CT) {
case TargetLowering::C_Immediate:
case TargetLowering::C_Other:
case TargetLowering::C_Unknown:
return 0;
case TargetLowering::C_Register:
return 1;
case TargetLowering::C_RegisterClass:
return 2;
case TargetLowering::C_Memory:
return 3;
}
llvm_unreachable("Invalid constraint type");
}
/// Examine constraint type and operand type and determine a weight value.
/// This object must already have been set up with the operand type
/// and the current alternative constraint selected.
TargetLowering::ConstraintWeight
TargetLowering::getMultipleConstraintMatchWeight(
AsmOperandInfo &info, int maIndex) const {
InlineAsm::ConstraintCodeVector *rCodes;
if (maIndex >= (int)info.multipleAlternatives.size())
rCodes = &info.Codes;
else
rCodes = &info.multipleAlternatives[maIndex].Codes;
ConstraintWeight BestWeight = CW_Invalid;
// Loop over the options, keeping track of the most general one.
for (unsigned i = 0, e = rCodes->size(); i != e; ++i) {
ConstraintWeight weight =
getSingleConstraintMatchWeight(info, (*rCodes)[i].c_str());
if (weight > BestWeight)
BestWeight = weight;
}
return BestWeight;
}
/// Examine constraint type and operand type and determine a weight value.
/// This object must already have been set up with the operand type
/// and the current alternative constraint selected.
TargetLowering::ConstraintWeight
TargetLowering::getSingleConstraintMatchWeight(
AsmOperandInfo &info, const char *constraint) const {
ConstraintWeight weight = CW_Invalid;
Value *CallOperandVal = info.CallOperandVal;
// If we don't have a value, we can't do a match,
// but allow it at the lowest weight.
if (!CallOperandVal)
return CW_Default;
// Look at the constraint type.
switch (*constraint) {
case 'i': // immediate integer.
case 'n': // immediate integer with a known value.
if (isa<ConstantInt>(CallOperandVal))
weight = CW_Constant;
break;
case 's': // non-explicit intregal immediate.
if (isa<GlobalValue>(CallOperandVal))
weight = CW_Constant;
break;
case 'E': // immediate float if host format.
case 'F': // immediate float.
if (isa<ConstantFP>(CallOperandVal))
weight = CW_Constant;
break;
case '<': // memory operand with autodecrement.
case '>': // memory operand with autoincrement.
case 'm': // memory operand.
case 'o': // offsettable memory operand
case 'V': // non-offsettable memory operand
weight = CW_Memory;
break;
case 'r': // general register.
case 'g': // general register, memory operand or immediate integer.
// note: Clang converts "g" to "imr".
if (CallOperandVal->getType()->isIntegerTy())
weight = CW_Register;
break;
case 'X': // any operand.
default:
weight = CW_Default;
break;
}
return weight;
}
/// If there are multiple different constraints that we could pick for this
/// operand (e.g. "imr") try to pick the 'best' one.
/// This is somewhat tricky: constraints fall into four classes:
/// Other -> immediates and magic values
/// Register -> one specific register
/// RegisterClass -> a group of regs
/// Memory -> memory
/// Ideally, we would pick the most specific constraint possible: if we have
/// something that fits into a register, we would pick it. The problem here
/// is that if we have something that could either be in a register or in
/// memory that use of the register could cause selection of *other*
/// operands to fail: they might only succeed if we pick memory. Because of
/// this the heuristic we use is:
///
/// 1) If there is an 'other' constraint, and if the operand is valid for
/// that constraint, use it. This makes us take advantage of 'i'
/// constraints when available.
/// 2) Otherwise, pick the most general constraint present. This prefers
/// 'm' over 'r', for example.
///
static void ChooseConstraint(TargetLowering::AsmOperandInfo &OpInfo,
const TargetLowering &TLI,
SDValue Op, SelectionDAG *DAG) {
assert(OpInfo.Codes.size() > 1 && "Doesn't have multiple constraint options");
unsigned BestIdx = 0;
TargetLowering::ConstraintType BestType = TargetLowering::C_Unknown;
int BestGenerality = -1;
// Loop over the options, keeping track of the most general one.
for (unsigned i = 0, e = OpInfo.Codes.size(); i != e; ++i) {
TargetLowering::ConstraintType CType =
TLI.getConstraintType(OpInfo.Codes[i]);
// Indirect 'other' or 'immediate' constraints are not allowed.
if (OpInfo.isIndirect && !(CType == TargetLowering::C_Memory ||
CType == TargetLowering::C_Register ||
CType == TargetLowering::C_RegisterClass))
continue;
// If this is an 'other' or 'immediate' constraint, see if the operand is
// valid for it. For example, on X86 we might have an 'rI' constraint. If
// the operand is an integer in the range [0..31] we want to use I (saving a
// load of a register), otherwise we must use 'r'.
if ((CType == TargetLowering::C_Other ||
CType == TargetLowering::C_Immediate) && Op.getNode()) {
assert(OpInfo.Codes[i].size() == 1 &&
"Unhandled multi-letter 'other' constraint");
std::vector<SDValue> ResultOps;
TLI.LowerAsmOperandForConstraint(Op, OpInfo.Codes[i],
ResultOps, *DAG);
if (!ResultOps.empty()) {
BestType = CType;
BestIdx = i;
break;
}
}
// Things with matching constraints can only be registers, per gcc
// documentation. This mainly affects "g" constraints.
if (CType == TargetLowering::C_Memory && OpInfo.hasMatchingInput())
continue;
// This constraint letter is more general than the previous one, use it.
int Generality = getConstraintGenerality(CType);
if (Generality > BestGenerality) {
BestType = CType;
BestIdx = i;
BestGenerality = Generality;
}
}
OpInfo.ConstraintCode = OpInfo.Codes[BestIdx];
OpInfo.ConstraintType = BestType;
}
/// Determines the constraint code and constraint type to use for the specific
/// AsmOperandInfo, setting OpInfo.ConstraintCode and OpInfo.ConstraintType.
void TargetLowering::ComputeConstraintToUse(AsmOperandInfo &OpInfo,
SDValue Op,
SelectionDAG *DAG) const {
assert(!OpInfo.Codes.empty() && "Must have at least one constraint");
// Single-letter constraints ('r') are very common.
if (OpInfo.Codes.size() == 1) {
OpInfo.ConstraintCode = OpInfo.Codes[0];
OpInfo.ConstraintType = getConstraintType(OpInfo.ConstraintCode);
} else {
ChooseConstraint(OpInfo, *this, Op, DAG);
}
// 'X' matches anything.
if (OpInfo.ConstraintCode == "X" && OpInfo.CallOperandVal) {
// Labels and constants are handled elsewhere ('X' is the only thing
// that matches labels). For Functions, the type here is the type of
// the result, which is not what we want to look at; leave them alone.
Value *v = OpInfo.CallOperandVal;
if (isa<BasicBlock>(v) || isa<ConstantInt>(v) || isa<Function>(v)) {
OpInfo.CallOperandVal = v;
return;
}
if (Op.getNode() && Op.getOpcode() == ISD::TargetBlockAddress)
return;
// Otherwise, try to resolve it to something we know about by looking at
// the actual operand type.
if (const char *Repl = LowerXConstraint(OpInfo.ConstraintVT)) {
OpInfo.ConstraintCode = Repl;
OpInfo.ConstraintType = getConstraintType(OpInfo.ConstraintCode);
}
}
}
/// Given an exact SDIV by a constant, create a multiplication
/// with the multiplicative inverse of the constant.
static SDValue BuildExactSDIV(const TargetLowering &TLI, SDNode *N,
const SDLoc &dl, SelectionDAG &DAG,
SmallVectorImpl<SDNode *> &Created) {
SDValue Op0 = N->getOperand(0);
SDValue Op1 = N->getOperand(1);
EVT VT = N->getValueType(0);
EVT SVT = VT.getScalarType();
EVT ShVT = TLI.getShiftAmountTy(VT, DAG.getDataLayout());
EVT ShSVT = ShVT.getScalarType();
bool UseSRA = false;
SmallVector<SDValue, 16> Shifts, Factors;
auto BuildSDIVPattern = [&](ConstantSDNode *C) {
if (C->isNullValue())
return false;
APInt Divisor = C->getAPIntValue();
unsigned Shift = Divisor.countTrailingZeros();
if (Shift) {
Divisor.ashrInPlace(Shift);
UseSRA = true;
}
// Calculate the multiplicative inverse, using Newton's method.
APInt t;
APInt Factor = Divisor;
while ((t = Divisor * Factor) != 1)
Factor *= APInt(Divisor.getBitWidth(), 2) - t;
Shifts.push_back(DAG.getConstant(Shift, dl, ShSVT));
Factors.push_back(DAG.getConstant(Factor, dl, SVT));
return true;
};
// Collect all magic values from the build vector.
if (!ISD::matchUnaryPredicate(Op1, BuildSDIVPattern))
return SDValue();
SDValue Shift, Factor;
if (VT.isVector()) {
Shift = DAG.getBuildVector(ShVT, dl, Shifts);
Factor = DAG.getBuildVector(VT, dl, Factors);
} else {
Shift = Shifts[0];
Factor = Factors[0];
}
SDValue Res = Op0;
// Shift the value upfront if it is even, so the LSB is one.
if (UseSRA) {
// TODO: For UDIV use SRL instead of SRA.
SDNodeFlags Flags;
Flags.setExact(true);
Res = DAG.getNode(ISD::SRA, dl, VT, Res, Shift, Flags);
Created.push_back(Res.getNode());
}
return DAG.getNode(ISD::MUL, dl, VT, Res, Factor);
}
SDValue TargetLowering::BuildSDIVPow2(SDNode *N, const APInt &Divisor,
SelectionDAG &DAG,
SmallVectorImpl<SDNode *> &Created) const {
AttributeList Attr = DAG.getMachineFunction().getFunction().getAttributes();
const TargetLowering &TLI = DAG.getTargetLoweringInfo();
if (TLI.isIntDivCheap(N->getValueType(0), Attr))
return SDValue(N, 0); // Lower SDIV as SDIV
return SDValue();
}
/// Given an ISD::SDIV node expressing a divide by constant,
/// return a DAG expression to select that will generate the same value by
/// multiplying by a magic number.
/// Ref: "Hacker's Delight" or "The PowerPC Compiler Writer's Guide".
SDValue TargetLowering::BuildSDIV(SDNode *N, SelectionDAG &DAG,
bool IsAfterLegalization,
SmallVectorImpl<SDNode *> &Created) const {
SDLoc dl(N);
EVT VT = N->getValueType(0);
EVT SVT = VT.getScalarType();
EVT ShVT = getShiftAmountTy(VT, DAG.getDataLayout());
EVT ShSVT = ShVT.getScalarType();
unsigned EltBits = VT.getScalarSizeInBits();
// Check to see if we can do this.
// FIXME: We should be more aggressive here.
if (!isTypeLegal(VT))
return SDValue();
// If the sdiv has an 'exact' bit we can use a simpler lowering.
if (N->getFlags().hasExact())
return BuildExactSDIV(*this, N, dl, DAG, Created);
SmallVector<SDValue, 16> MagicFactors, Factors, Shifts, ShiftMasks;
auto BuildSDIVPattern = [&](ConstantSDNode *C) {
if (C->isNullValue())
return false;
const APInt &Divisor = C->getAPIntValue();
APInt::ms magics = Divisor.magic();
int NumeratorFactor = 0;
int ShiftMask = -1;
if (Divisor.isOneValue() || Divisor.isAllOnesValue()) {
// If d is +1/-1, we just multiply the numerator by +1/-1.
NumeratorFactor = Divisor.getSExtValue();
magics.m = 0;
magics.s = 0;
ShiftMask = 0;
} else if (Divisor.isStrictlyPositive() && magics.m.isNegative()) {
// If d > 0 and m < 0, add the numerator.
NumeratorFactor = 1;
} else if (Divisor.isNegative() && magics.m.isStrictlyPositive()) {
// If d < 0 and m > 0, subtract the numerator.
NumeratorFactor = -1;
}
MagicFactors.push_back(DAG.getConstant(magics.m, dl, SVT));
Factors.push_back(DAG.getConstant(NumeratorFactor, dl, SVT));
Shifts.push_back(DAG.getConstant(magics.s, dl, ShSVT));
ShiftMasks.push_back(DAG.getConstant(ShiftMask, dl, SVT));
return true;
};
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
// Collect the shifts / magic values from each element.
if (!ISD::matchUnaryPredicate(N1, BuildSDIVPattern))
return SDValue();
SDValue MagicFactor, Factor, Shift, ShiftMask;
if (VT.isVector()) {
MagicFactor = DAG.getBuildVector(VT, dl, MagicFactors);
Factor = DAG.getBuildVector(VT, dl, Factors);
Shift = DAG.getBuildVector(ShVT, dl, Shifts);
ShiftMask = DAG.getBuildVector(VT, dl, ShiftMasks);
} else {
MagicFactor = MagicFactors[0];
Factor = Factors[0];
Shift = Shifts[0];
ShiftMask = ShiftMasks[0];
}
// Multiply the numerator (operand 0) by the magic value.
// FIXME: We should support doing a MUL in a wider type.
SDValue Q;
if (IsAfterLegalization ? isOperationLegal(ISD::MULHS, VT)
: isOperationLegalOrCustom(ISD::MULHS, VT))
Q = DAG.getNode(ISD::MULHS, dl, VT, N0, MagicFactor);
else if (IsAfterLegalization ? isOperationLegal(ISD::SMUL_LOHI, VT)
: isOperationLegalOrCustom(ISD::SMUL_LOHI, VT)) {
SDValue LoHi =
DAG.getNode(ISD::SMUL_LOHI, dl, DAG.getVTList(VT, VT), N0, MagicFactor);
Q = SDValue(LoHi.getNode(), 1);
} else
return SDValue(); // No mulhs or equivalent.
Created.push_back(Q.getNode());
// (Optionally) Add/subtract the numerator using Factor.
Factor = DAG.getNode(ISD::MUL, dl, VT, N0, Factor);
Created.push_back(Factor.getNode());
Q = DAG.getNode(ISD::ADD, dl, VT, Q, Factor);
Created.push_back(Q.getNode());
// Shift right algebraic by shift value.
Q = DAG.getNode(ISD::SRA, dl, VT, Q, Shift);
Created.push_back(Q.getNode());
// Extract the sign bit, mask it and add it to the quotient.
SDValue SignShift = DAG.getConstant(EltBits - 1, dl, ShVT);
SDValue T = DAG.getNode(ISD::SRL, dl, VT, Q, SignShift);
Created.push_back(T.getNode());
T = DAG.getNode(ISD::AND, dl, VT, T, ShiftMask);
Created.push_back(T.getNode());
return DAG.getNode(ISD::ADD, dl, VT, Q, T);
}
/// Given an ISD::UDIV node expressing a divide by constant,
/// return a DAG expression to select that will generate the same value by
/// multiplying by a magic number.
/// Ref: "Hacker's Delight" or "The PowerPC Compiler Writer's Guide".
SDValue TargetLowering::BuildUDIV(SDNode *N, SelectionDAG &DAG,
bool IsAfterLegalization,
SmallVectorImpl<SDNode *> &Created) const {
SDLoc dl(N);
EVT VT = N->getValueType(0);
EVT SVT = VT.getScalarType();
EVT ShVT = getShiftAmountTy(VT, DAG.getDataLayout());
EVT ShSVT = ShVT.getScalarType();
unsigned EltBits = VT.getScalarSizeInBits();
// Check to see if we can do this.
// FIXME: We should be more aggressive here.
if (!isTypeLegal(VT))
return SDValue();
bool UseNPQ = false;
SmallVector<SDValue, 16> PreShifts, PostShifts, MagicFactors, NPQFactors;
auto BuildUDIVPattern = [&](ConstantSDNode *C) {
if (C->isNullValue())
return false;
// FIXME: We should use a narrower constant when the upper
// bits are known to be zero.
APInt Divisor = C->getAPIntValue();
APInt::mu magics = Divisor.magicu();
unsigned PreShift = 0, PostShift = 0;
// If the divisor is even, we can avoid using the expensive fixup by
// shifting the divided value upfront.
if (magics.a != 0 && !Divisor[0]) {
PreShift = Divisor.countTrailingZeros();
// Get magic number for the shifted divisor.
magics = Divisor.lshr(PreShift).magicu(PreShift);
assert(magics.a == 0 && "Should use cheap fixup now");
}
APInt Magic = magics.m;
unsigned SelNPQ;
if (magics.a == 0 || Divisor.isOneValue()) {
assert(magics.s < Divisor.getBitWidth() &&
"We shouldn't generate an undefined shift!");
PostShift = magics.s;
SelNPQ = false;
} else {
PostShift = magics.s - 1;
SelNPQ = true;
}
PreShifts.push_back(DAG.getConstant(PreShift, dl, ShSVT));
MagicFactors.push_back(DAG.getConstant(Magic, dl, SVT));
NPQFactors.push_back(
DAG.getConstant(SelNPQ ? APInt::getOneBitSet(EltBits, EltBits - 1)
: APInt::getNullValue(EltBits),
dl, SVT));
PostShifts.push_back(DAG.getConstant(PostShift, dl, ShSVT));
UseNPQ |= SelNPQ;
return true;
};
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
// Collect the shifts/magic values from each element.
if (!ISD::matchUnaryPredicate(N1, BuildUDIVPattern))
return SDValue();
SDValue PreShift, PostShift, MagicFactor, NPQFactor;
if (VT.isVector()) {
PreShift = DAG.getBuildVector(ShVT, dl, PreShifts);
MagicFactor = DAG.getBuildVector(VT, dl, MagicFactors);
NPQFactor = DAG.getBuildVector(VT, dl, NPQFactors);
PostShift = DAG.getBuildVector(ShVT, dl, PostShifts);
} else {
PreShift = PreShifts[0];
MagicFactor = MagicFactors[0];
PostShift = PostShifts[0];
}
SDValue Q = N0;
Q = DAG.getNode(ISD::SRL, dl, VT, Q, PreShift);
Created.push_back(Q.getNode());
// FIXME: We should support doing a MUL in a wider type.
auto GetMULHU = [&](SDValue X, SDValue Y) {
if (IsAfterLegalization ? isOperationLegal(ISD::MULHU, VT)
: isOperationLegalOrCustom(ISD::MULHU, VT))
return DAG.getNode(ISD::MULHU, dl, VT, X, Y);
if (IsAfterLegalization ? isOperationLegal(ISD::UMUL_LOHI, VT)
: isOperationLegalOrCustom(ISD::UMUL_LOHI, VT)) {
SDValue LoHi =
DAG.getNode(ISD::UMUL_LOHI, dl, DAG.getVTList(VT, VT), X, Y);
return SDValue(LoHi.getNode(), 1);
}
return SDValue(); // No mulhu or equivalent
};
// Multiply the numerator (operand 0) by the magic value.
Q = GetMULHU(Q, MagicFactor);
if (!Q)
return SDValue();
Created.push_back(Q.getNode());
if (UseNPQ) {
SDValue NPQ = DAG.getNode(ISD::SUB, dl, VT, N0, Q);
Created.push_back(NPQ.getNode());
// For vectors we might have a mix of non-NPQ/NPQ paths, so use
// MULHU to act as a SRL-by-1 for NPQ, else multiply by zero.
if (VT.isVector())
NPQ = GetMULHU(NPQ, NPQFactor);
else
NPQ = DAG.getNode(ISD::SRL, dl, VT, NPQ, DAG.getConstant(1, dl, ShVT));
Created.push_back(NPQ.getNode());
Q = DAG.getNode(ISD::ADD, dl, VT, NPQ, Q);
Created.push_back(Q.getNode());
}
Q = DAG.getNode(ISD::SRL, dl, VT, Q, PostShift);
Created.push_back(Q.getNode());
SDValue One = DAG.getConstant(1, dl, VT);
SDValue IsOne = DAG.getSetCC(dl, VT, N1, One, ISD::SETEQ);
return DAG.getSelect(dl, VT, IsOne, N0, Q);
}
/// If all values in Values that *don't* match the predicate are same 'splat'
/// value, then replace all values with that splat value.
/// Else, if AlternativeReplacement was provided, then replace all values that
/// do match predicate with AlternativeReplacement value.
static void
turnVectorIntoSplatVector(MutableArrayRef<SDValue> Values,
std::function<bool(SDValue)> Predicate,
SDValue AlternativeReplacement = SDValue()) {
SDValue Replacement;
// Is there a value for which the Predicate does *NOT* match? What is it?
auto SplatValue = llvm::find_if_not(Values, Predicate);
if (SplatValue != Values.end()) {
// Does Values consist only of SplatValue's and values matching Predicate?
if (llvm::all_of(Values, [Predicate, SplatValue](SDValue Value) {
return Value == *SplatValue || Predicate(Value);
})) // Then we shall replace values matching predicate with SplatValue.
Replacement = *SplatValue;
}
if (!Replacement) {
// Oops, we did not find the "baseline" splat value.
if (!AlternativeReplacement)
return; // Nothing to do.
// Let's replace with provided value then.
Replacement = AlternativeReplacement;
}
std::replace_if(Values.begin(), Values.end(), Predicate, Replacement);
}
/// Given an ISD::UREM used only by an ISD::SETEQ or ISD::SETNE
/// where the divisor is constant and the comparison target is zero,
/// return a DAG expression that will generate the same comparison result
/// using only multiplications, additions and shifts/rotations.
/// Ref: "Hacker's Delight" 10-17.
SDValue TargetLowering::buildUREMEqFold(EVT SETCCVT, SDValue REMNode,
SDValue CompTargetNode,
ISD::CondCode Cond,
DAGCombinerInfo &DCI,
const SDLoc &DL) const {
SmallVector<SDNode *, 5> Built;
if (SDValue Folded = prepareUREMEqFold(SETCCVT, REMNode, CompTargetNode, Cond,
DCI, DL, Built)) {
for (SDNode *N : Built)
DCI.AddToWorklist(N);
return Folded;
}
return SDValue();
}
SDValue
TargetLowering::prepareUREMEqFold(EVT SETCCVT, SDValue REMNode,
SDValue CompTargetNode, ISD::CondCode Cond,
DAGCombinerInfo &DCI, const SDLoc &DL,
SmallVectorImpl<SDNode *> &Created) const {
// fold (seteq/ne (urem N, D), 0) -> (setule/ugt (rotr (mul N, P), K), Q)
// - D must be constant, with D = D0 * 2^K where D0 is odd
// - P is the multiplicative inverse of D0 modulo 2^W
// - Q = floor(((2^W) - 1) / D)
// where W is the width of the common type of N and D.
assert((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
"Only applicable for (in)equality comparisons.");
SelectionDAG &DAG = DCI.DAG;
EVT VT = REMNode.getValueType();
EVT SVT = VT.getScalarType();
EVT ShVT = getShiftAmountTy(VT, DAG.getDataLayout());
EVT ShSVT = ShVT.getScalarType();
// If MUL is unavailable, we cannot proceed in any case.
if (!isOperationLegalOrCustom(ISD::MUL, VT))
return SDValue();
bool ComparingWithAllZeros = true;
bool AllComparisonsWithNonZerosAreTautological = true;
bool HadTautologicalLanes = false;
bool AllLanesAreTautological = true;
bool HadEvenDivisor = false;
bool AllDivisorsArePowerOfTwo = true;
bool HadTautologicalInvertedLanes = false;
SmallVector<SDValue, 16> PAmts, KAmts, QAmts, IAmts;
auto BuildUREMPattern = [&](ConstantSDNode *CDiv, ConstantSDNode *CCmp) {
// Division by 0 is UB. Leave it to be constant-folded elsewhere.
if (CDiv->isNullValue())
return false;
const APInt &D = CDiv->getAPIntValue();
const APInt &Cmp = CCmp->getAPIntValue();
ComparingWithAllZeros &= Cmp.isNullValue();
// x u% C1` is *always* less than C1. So given `x u% C1 == C2`,
// if C2 is not less than C1, the comparison is always false.
// But we will only be able to produce the comparison that will give the
// opposive tautological answer. So this lane would need to be fixed up.
bool TautologicalInvertedLane = D.ule(Cmp);
HadTautologicalInvertedLanes |= TautologicalInvertedLane;
// If all lanes are tautological (either all divisors are ones, or divisor
// is not greater than the constant we are comparing with),
// we will prefer to avoid the fold.
bool TautologicalLane = D.isOneValue() || TautologicalInvertedLane;
HadTautologicalLanes |= TautologicalLane;
AllLanesAreTautological &= TautologicalLane;
// If we are comparing with non-zero, we need'll need to subtract said
// comparison value from the LHS. But there is no point in doing that if
// every lane where we are comparing with non-zero is tautological..
if (!Cmp.isNullValue())
AllComparisonsWithNonZerosAreTautological &= TautologicalLane;
// Decompose D into D0 * 2^K
unsigned K = D.countTrailingZeros();
assert((!D.isOneValue() || (K == 0)) && "For divisor '1' we won't rotate.");
APInt D0 = D.lshr(K);
// D is even if it has trailing zeros.
HadEvenDivisor |= (K != 0);
// D is a power-of-two if D0 is one.
// If all divisors are power-of-two, we will prefer to avoid the fold.
AllDivisorsArePowerOfTwo &= D0.isOneValue();
// P = inv(D0, 2^W)
// 2^W requires W + 1 bits, so we have to extend and then truncate.
unsigned W = D.getBitWidth();
APInt P = D0.zext(W + 1)
.multiplicativeInverse(APInt::getSignedMinValue(W + 1))
.trunc(W);
assert(!P.isNullValue() && "No multiplicative inverse!"); // unreachable
assert((D0 * P).isOneValue() && "Multiplicative inverse sanity check.");
// Q = floor((2^W - 1) u/ D)
// R = ((2^W - 1) u% D)
APInt Q, R;
APInt::udivrem(APInt::getAllOnesValue(W), D, Q, R);
// If we are comparing with zero, then that comparison constant is okay,
// else it may need to be one less than that.
if (Cmp.ugt(R))
Q -= 1;
assert(APInt::getAllOnesValue(ShSVT.getSizeInBits()).ugt(K) &&
"We are expecting that K is always less than all-ones for ShSVT");
// If the lane is tautological the result can be constant-folded.
if (TautologicalLane) {
// Set P and K amount to a bogus values so we can try to splat them.
P = 0;
K = -1;
// And ensure that comparison constant is tautological,
// it will always compare true/false.
Q = -1;
}
PAmts.push_back(DAG.getConstant(P, DL, SVT));
KAmts.push_back(
DAG.getConstant(APInt(ShSVT.getSizeInBits(), K), DL, ShSVT));
QAmts.push_back(DAG.getConstant(Q, DL, SVT));
return true;
};
SDValue N = REMNode.getOperand(0);
SDValue D = REMNode.getOperand(1);
// Collect the values from each element.
if (!ISD::matchBinaryPredicate(D, CompTargetNode, BuildUREMPattern))
return SDValue();
// If all lanes are tautological, the result can be constant-folded.
if (AllLanesAreTautological)
return SDValue();
// If this is a urem by a powers-of-two, avoid the fold since it can be
// best implemented as a bit test.
if (AllDivisorsArePowerOfTwo)
return SDValue();
SDValue PVal, KVal, QVal;
if (VT.isVector()) {
if (HadTautologicalLanes) {
// Try to turn PAmts into a splat, since we don't care about the values
// that are currently '0'. If we can't, just keep '0'`s.
turnVectorIntoSplatVector(PAmts, isNullConstant);
// Try to turn KAmts into a splat, since we don't care about the values
// that are currently '-1'. If we can't, change them to '0'`s.
turnVectorIntoSplatVector(KAmts, isAllOnesConstant,
DAG.getConstant(0, DL, ShSVT));
}
PVal = DAG.getBuildVector(VT, DL, PAmts);
KVal = DAG.getBuildVector(ShVT, DL, KAmts);
QVal = DAG.getBuildVector(VT, DL, QAmts);
} else {
PVal = PAmts[0];
KVal = KAmts[0];
QVal = QAmts[0];
}
if (!ComparingWithAllZeros && !AllComparisonsWithNonZerosAreTautological) {
if (!isOperationLegalOrCustom(ISD::SUB, VT))
return SDValue(); // FIXME: Could/should use `ISD::ADD`?
assert(CompTargetNode.getValueType() == N.getValueType() &&
"Expecting that the types on LHS and RHS of comparisons match.");
N = DAG.getNode(ISD::SUB, DL, VT, N, CompTargetNode);
}
// (mul N, P)
SDValue Op0 = DAG.getNode(ISD::MUL, DL, VT, N, PVal);
Created.push_back(Op0.getNode());
// Rotate right only if any divisor was even. We avoid rotates for all-odd
// divisors as a performance improvement, since rotating by 0 is a no-op.
if (HadEvenDivisor) {
// We need ROTR to do this.
if (!isOperationLegalOrCustom(ISD::ROTR, VT))
return SDValue();
SDNodeFlags Flags;
Flags.setExact(true);
// UREM: (rotr (mul N, P), K)
Op0 = DAG.getNode(ISD::ROTR, DL, VT, Op0, KVal, Flags);
Created.push_back(Op0.getNode());
}
// UREM: (setule/setugt (rotr (mul N, P), K), Q)
SDValue NewCC =
DAG.getSetCC(DL, SETCCVT, Op0, QVal,
((Cond == ISD::SETEQ) ? ISD::SETULE : ISD::SETUGT));
if (!HadTautologicalInvertedLanes)
return NewCC;
// If any lanes previously compared always-false, the NewCC will give
// always-true result for them, so we need to fixup those lanes.
// Or the other way around for inequality predicate.
assert(VT.isVector() && "Can/should only get here for vectors.");
Created.push_back(NewCC.getNode());
// x u% C1` is *always* less than C1. So given `x u% C1 == C2`,
// if C2 is not less than C1, the comparison is always false.
// But we have produced the comparison that will give the
// opposive tautological answer. So these lanes would need to be fixed up.
SDValue TautologicalInvertedChannels =
DAG.getSetCC(DL, SETCCVT, D, CompTargetNode, ISD::SETULE);
Created.push_back(TautologicalInvertedChannels.getNode());
if (isOperationLegalOrCustom(ISD::VSELECT, SETCCVT)) {
// If we have a vector select, let's replace the comparison results in the
// affected lanes with the correct tautological result.
SDValue Replacement = DAG.getBoolConstant(Cond == ISD::SETEQ ? false : true,
DL, SETCCVT, SETCCVT);
return DAG.getNode(ISD::VSELECT, DL, SETCCVT, TautologicalInvertedChannels,
Replacement, NewCC);
}
// Else, we can just invert the comparison result in the appropriate lanes.
if (isOperationLegalOrCustom(ISD::XOR, SETCCVT))
return DAG.getNode(ISD::XOR, DL, SETCCVT, NewCC,
TautologicalInvertedChannels);
return SDValue(); // Don't know how to lower.
}
/// Given an ISD::SREM used only by an ISD::SETEQ or ISD::SETNE
/// where the divisor is constant and the comparison target is zero,
/// return a DAG expression that will generate the same comparison result
/// using only multiplications, additions and shifts/rotations.
/// Ref: "Hacker's Delight" 10-17.
SDValue TargetLowering::buildSREMEqFold(EVT SETCCVT, SDValue REMNode,
SDValue CompTargetNode,
ISD::CondCode Cond,
DAGCombinerInfo &DCI,
const SDLoc &DL) const {
SmallVector<SDNode *, 7> Built;
if (SDValue Folded = prepareSREMEqFold(SETCCVT, REMNode, CompTargetNode, Cond,
DCI, DL, Built)) {
assert(Built.size() <= 7 && "Max size prediction failed.");
for (SDNode *N : Built)
DCI.AddToWorklist(N);
return Folded;
}
return SDValue();
}
SDValue
TargetLowering::prepareSREMEqFold(EVT SETCCVT, SDValue REMNode,
SDValue CompTargetNode, ISD::CondCode Cond,
DAGCombinerInfo &DCI, const SDLoc &DL,
SmallVectorImpl<SDNode *> &Created) const {
// Fold:
// (seteq/ne (srem N, D), 0)
// To:
// (setule/ugt (rotr (add (mul N, P), A), K), Q)
//
// - D must be constant, with D = D0 * 2^K where D0 is odd
// - P is the multiplicative inverse of D0 modulo 2^W
// - A = bitwiseand(floor((2^(W - 1) - 1) / D0), (-(2^k)))
// - Q = floor((2 * A) / (2^K))
// where W is the width of the common type of N and D.
assert((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
"Only applicable for (in)equality comparisons.");
SelectionDAG &DAG = DCI.DAG;
EVT VT = REMNode.getValueType();
EVT SVT = VT.getScalarType();
EVT ShVT = getShiftAmountTy(VT, DAG.getDataLayout());
EVT ShSVT = ShVT.getScalarType();
// If MUL is unavailable, we cannot proceed in any case.
if (!isOperationLegalOrCustom(ISD::MUL, VT))
return SDValue();
// TODO: Could support comparing with non-zero too.
ConstantSDNode *CompTarget = isConstOrConstSplat(CompTargetNode);
if (!CompTarget || !CompTarget->isNullValue())
return SDValue();
bool HadIntMinDivisor = false;
bool HadOneDivisor = false;
bool AllDivisorsAreOnes = true;
bool HadEvenDivisor = false;
bool NeedToApplyOffset = false;
bool AllDivisorsArePowerOfTwo = true;
SmallVector<SDValue, 16> PAmts, AAmts, KAmts, QAmts;
auto BuildSREMPattern = [&](ConstantSDNode *C) {
// Division by 0 is UB. Leave it to be constant-folded elsewhere.
if (C->isNullValue())
return false;
// FIXME: we don't fold `rem %X, -C` to `rem %X, C` in DAGCombine.
// WARNING: this fold is only valid for positive divisors!
APInt D = C->getAPIntValue();
if (D.isNegative())
D.negate(); // `rem %X, -C` is equivalent to `rem %X, C`
HadIntMinDivisor |= D.isMinSignedValue();
// If all divisors are ones, we will prefer to avoid the fold.
HadOneDivisor |= D.isOneValue();
AllDivisorsAreOnes &= D.isOneValue();
// Decompose D into D0 * 2^K
unsigned K = D.countTrailingZeros();
assert((!D.isOneValue() || (K == 0)) && "For divisor '1' we won't rotate.");
APInt D0 = D.lshr(K);
if (!D.isMinSignedValue()) {
// D is even if it has trailing zeros; unless it's INT_MIN, in which case
// we don't care about this lane in this fold, we'll special-handle it.
HadEvenDivisor |= (K != 0);
}
// D is a power-of-two if D0 is one. This includes INT_MIN.
// If all divisors are power-of-two, we will prefer to avoid the fold.
AllDivisorsArePowerOfTwo &= D0.isOneValue();
// P = inv(D0, 2^W)
// 2^W requires W + 1 bits, so we have to extend and then truncate.
unsigned W = D.getBitWidth();
APInt P = D0.zext(W + 1)
.multiplicativeInverse(APInt::getSignedMinValue(W + 1))
.trunc(W);
assert(!P.isNullValue() && "No multiplicative inverse!"); // unreachable
assert((D0 * P).isOneValue() && "Multiplicative inverse sanity check.");
// A = floor((2^(W - 1) - 1) / D0) & -2^K
APInt A = APInt::getSignedMaxValue(W).udiv(D0);
A.clearLowBits(K);
if (!D.isMinSignedValue()) {
// If divisor INT_MIN, then we don't care about this lane in this fold,
// we'll special-handle it.
NeedToApplyOffset |= A != 0;
}
// Q = floor((2 * A) / (2^K))
APInt Q = (2 * A).udiv(APInt::getOneBitSet(W, K));
assert(APInt::getAllOnesValue(SVT.getSizeInBits()).ugt(A) &&
"We are expecting that A is always less than all-ones for SVT");
assert(APInt::getAllOnesValue(ShSVT.getSizeInBits()).ugt(K) &&
"We are expecting that K is always less than all-ones for ShSVT");
// If the divisor is 1 the result can be constant-folded. Likewise, we
// don't care about INT_MIN lanes, those can be set to undef if appropriate.
if (D.isOneValue()) {
// Set P, A and K to a bogus values so we can try to splat them.
P = 0;
A = -1;
K = -1;
// x ?% 1 == 0 <--> true <--> x u<= -1
Q = -1;
}
PAmts.push_back(DAG.getConstant(P, DL, SVT));
AAmts.push_back(DAG.getConstant(A, DL, SVT));
KAmts.push_back(
DAG.getConstant(APInt(ShSVT.getSizeInBits(), K), DL, ShSVT));
QAmts.push_back(DAG.getConstant(Q, DL, SVT));
return true;
};
SDValue N = REMNode.getOperand(0);
SDValue D = REMNode.getOperand(1);
// Collect the values from each element.
if (!ISD::matchUnaryPredicate(D, BuildSREMPattern))
return SDValue();
// If this is a srem by a one, avoid the fold since it can be constant-folded.
if (AllDivisorsAreOnes)
return SDValue();
// If this is a srem by a powers-of-two (including INT_MIN), avoid the fold
// since it can be best implemented as a bit test.
if (AllDivisorsArePowerOfTwo)
return SDValue();
SDValue PVal, AVal, KVal, QVal;
if (VT.isVector()) {
if (HadOneDivisor) {
// Try to turn PAmts into a splat, since we don't care about the values
// that are currently '0'. If we can't, just keep '0'`s.
turnVectorIntoSplatVector(PAmts, isNullConstant);
// Try to turn AAmts into a splat, since we don't care about the
// values that are currently '-1'. If we can't, change them to '0'`s.
turnVectorIntoSplatVector(AAmts, isAllOnesConstant,
DAG.getConstant(0, DL, SVT));
// Try to turn KAmts into a splat, since we don't care about the values
// that are currently '-1'. If we can't, change them to '0'`s.
turnVectorIntoSplatVector(KAmts, isAllOnesConstant,
DAG.getConstant(0, DL, ShSVT));
}
PVal = DAG.getBuildVector(VT, DL, PAmts);
AVal = DAG.getBuildVector(VT, DL, AAmts);
KVal = DAG.getBuildVector(ShVT, DL, KAmts);
QVal = DAG.getBuildVector(VT, DL, QAmts);
} else {
PVal = PAmts[0];
AVal = AAmts[0];
KVal = KAmts[0];
QVal = QAmts[0];
}
// (mul N, P)
SDValue Op0 = DAG.getNode(ISD::MUL, DL, VT, N, PVal);
Created.push_back(Op0.getNode());
if (NeedToApplyOffset) {
// We need ADD to do this.
if (!isOperationLegalOrCustom(ISD::ADD, VT))
return SDValue();
// (add (mul N, P), A)
Op0 = DAG.getNode(ISD::ADD, DL, VT, Op0, AVal);
Created.push_back(Op0.getNode());
}
// Rotate right only if any divisor was even. We avoid rotates for all-odd
// divisors as a performance improvement, since rotating by 0 is a no-op.
if (HadEvenDivisor) {
// We need ROTR to do this.
if (!isOperationLegalOrCustom(ISD::ROTR, VT))
return SDValue();
SDNodeFlags Flags;
Flags.setExact(true);
// SREM: (rotr (add (mul N, P), A), K)
Op0 = DAG.getNode(ISD::ROTR, DL, VT, Op0, KVal, Flags);
Created.push_back(Op0.getNode());
}
// SREM: (setule/setugt (rotr (add (mul N, P), A), K), Q)
SDValue Fold =
DAG.getSetCC(DL, SETCCVT, Op0, QVal,
((Cond == ISD::SETEQ) ? ISD::SETULE : ISD::SETUGT));
// If we didn't have lanes with INT_MIN divisor, then we're done.
if (!HadIntMinDivisor)
return Fold;
// That fold is only valid for positive divisors. Which effectively means,
// it is invalid for INT_MIN divisors. So if we have such a lane,
// we must fix-up results for said lanes.
assert(VT.isVector() && "Can/should only get here for vectors.");
if (!isOperationLegalOrCustom(ISD::SETEQ, VT) ||
!isOperationLegalOrCustom(ISD::AND, VT) ||
!isOperationLegalOrCustom(Cond, VT) ||
!isOperationLegalOrCustom(ISD::VSELECT, VT))
return SDValue();
Created.push_back(Fold.getNode());
SDValue IntMin = DAG.getConstant(
APInt::getSignedMinValue(SVT.getScalarSizeInBits()), DL, VT);
SDValue IntMax = DAG.getConstant(
APInt::getSignedMaxValue(SVT.getScalarSizeInBits()), DL, VT);
SDValue Zero =
DAG.getConstant(APInt::getNullValue(SVT.getScalarSizeInBits()), DL, VT);
// Which lanes had INT_MIN divisors? Divisor is constant, so const-folded.
SDValue DivisorIsIntMin = DAG.getSetCC(DL, SETCCVT, D, IntMin, ISD::SETEQ);
Created.push_back(DivisorIsIntMin.getNode());
// (N s% INT_MIN) ==/!= 0 <--> (N & INT_MAX) ==/!= 0
SDValue Masked = DAG.getNode(ISD::AND, DL, VT, N, IntMax);
Created.push_back(Masked.getNode());
SDValue MaskedIsZero = DAG.getSetCC(DL, SETCCVT, Masked, Zero, Cond);
Created.push_back(MaskedIsZero.getNode());
// To produce final result we need to blend 2 vectors: 'SetCC' and
// 'MaskedIsZero'. If the divisor for channel was *NOT* INT_MIN, we pick
// from 'Fold', else pick from 'MaskedIsZero'. Since 'DivisorIsIntMin' is
// constant-folded, select can get lowered to a shuffle with constant mask.
SDValue Blended =
DAG.getNode(ISD::VSELECT, DL, VT, DivisorIsIntMin, MaskedIsZero, Fold);
return Blended;
}
bool TargetLowering::
verifyReturnAddressArgumentIsConstant(SDValue Op, SelectionDAG &DAG) const {
if (!isa<ConstantSDNode>(Op.getOperand(0))) {
DAG.getContext()->emitError("argument to '__builtin_return_address' must "
"be a constant integer");
return true;
}
return false;
}
SDValue TargetLowering::getNegatedExpression(SDValue Op, SelectionDAG &DAG,
bool LegalOps, bool OptForSize,
NegatibleCost &Cost,
unsigned Depth) const {
// fneg is removable even if it has multiple uses.
if (Op.getOpcode() == ISD::FNEG) {
Cost = NegatibleCost::Cheaper;
return Op.getOperand(0);
}
// Don't recurse exponentially.
if (Depth > SelectionDAG::MaxRecursionDepth)
return SDValue();
// Pre-increment recursion depth for use in recursive calls.
++Depth;
const SDNodeFlags Flags = Op->getFlags();
const TargetOptions &Options = DAG.getTarget().Options;
EVT VT = Op.getValueType();
unsigned Opcode = Op.getOpcode();
// Don't allow anything with multiple uses unless we know it is free.
if (!Op.hasOneUse() && Opcode != ISD::ConstantFP) {
bool IsFreeExtend = Opcode == ISD::FP_EXTEND &&
isFPExtFree(VT, Op.getOperand(0).getValueType());
if (!IsFreeExtend)
return SDValue();
}
SDLoc DL(Op);
switch (Opcode) {
case ISD::ConstantFP: {
// Don't invert constant FP values after legalization unless the target says
// the negated constant is legal.
bool IsOpLegal =
isOperationLegal(ISD::ConstantFP, VT) ||
isFPImmLegal(neg(cast<ConstantFPSDNode>(Op)->getValueAPF()), VT,
OptForSize);
if (LegalOps && !IsOpLegal)
break;
APFloat V = cast<ConstantFPSDNode>(Op)->getValueAPF();
V.changeSign();
SDValue CFP = DAG.getConstantFP(V, DL, VT);
// If we already have the use of the negated floating constant, it is free
// to negate it even it has multiple uses.
if (!Op.hasOneUse() && CFP.use_empty())
break;
Cost = NegatibleCost::Neutral;
return CFP;
}
case ISD::BUILD_VECTOR: {
// Only permit BUILD_VECTOR of constants.
if (llvm::any_of(Op->op_values(), [&](SDValue N) {
return !N.isUndef() && !isa<ConstantFPSDNode>(N);
}))
break;
bool IsOpLegal =
(isOperationLegal(ISD::ConstantFP, VT) &&
isOperationLegal(ISD::BUILD_VECTOR, VT)) ||
llvm::all_of(Op->op_values(), [&](SDValue N) {
return N.isUndef() ||
isFPImmLegal(neg(cast<ConstantFPSDNode>(N)->getValueAPF()), VT,
OptForSize);
});
if (LegalOps && !IsOpLegal)
break;
SmallVector<SDValue, 4> Ops;
for (SDValue C : Op->op_values()) {
if (C.isUndef()) {
Ops.push_back(C);
continue;
}
APFloat V = cast<ConstantFPSDNode>(C)->getValueAPF();
V.changeSign();
Ops.push_back(DAG.getConstantFP(V, DL, C.getValueType()));
}
Cost = NegatibleCost::Neutral;
return DAG.getBuildVector(VT, DL, Ops);
}
case ISD::FADD: {
if (!Options.NoSignedZerosFPMath && !Flags.hasNoSignedZeros())
break;
// After operation legalization, it might not be legal to create new FSUBs.
if (LegalOps && !isOperationLegalOrCustom(ISD::FSUB, VT))
break;
SDValue X = Op.getOperand(0), Y = Op.getOperand(1);
// fold (fneg (fadd X, Y)) -> (fsub (fneg X), Y)
NegatibleCost CostX = NegatibleCost::Expensive;
SDValue NegX =
getNegatedExpression(X, DAG, LegalOps, OptForSize, CostX, Depth);
// fold (fneg (fadd X, Y)) -> (fsub (fneg Y), X)
NegatibleCost CostY = NegatibleCost::Expensive;
SDValue NegY =
getNegatedExpression(Y, DAG, LegalOps, OptForSize, CostY, Depth);
// Negate the X if its cost is less or equal than Y.
if (NegX && (CostX <= CostY)) {
Cost = CostX;
return DAG.getNode(ISD::FSUB, DL, VT, NegX, Y, Flags);
}
// Negate the Y if it is not expensive.
if (NegY) {
Cost = CostY;
return DAG.getNode(ISD::FSUB, DL, VT, NegY, X, Flags);
}
break;
}
case ISD::FSUB: {
// We can't turn -(A-B) into B-A when we honor signed zeros.
if (!Options.NoSignedZerosFPMath && !Flags.hasNoSignedZeros())
break;
SDValue X = Op.getOperand(0), Y = Op.getOperand(1);
// fold (fneg (fsub 0, Y)) -> Y
if (ConstantFPSDNode *C = isConstOrConstSplatFP(X, /*AllowUndefs*/ true))
if (C->isZero()) {
Cost = NegatibleCost::Cheaper;
return Y;
}
// fold (fneg (fsub X, Y)) -> (fsub Y, X)
Cost = NegatibleCost::Neutral;
return DAG.getNode(ISD::FSUB, DL, VT, Y, X, Flags);
}
case ISD::FMUL:
case ISD::FDIV: {
SDValue X = Op.getOperand(0), Y = Op.getOperand(1);
// fold (fneg (fmul X, Y)) -> (fmul (fneg X), Y)
NegatibleCost CostX = NegatibleCost::Expensive;
SDValue NegX =
getNegatedExpression(X, DAG, LegalOps, OptForSize, CostX, Depth);
// fold (fneg (fmul X, Y)) -> (fmul X, (fneg Y))
NegatibleCost CostY = NegatibleCost::Expensive;
SDValue NegY =
getNegatedExpression(Y, DAG, LegalOps, OptForSize, CostY, Depth);
// Negate the X if its cost is less or equal than Y.
if (NegX && (CostX <= CostY)) {
Cost = CostX;
return DAG.getNode(Opcode, DL, VT, NegX, Y, Flags);
}
// Ignore X * 2.0 because that is expected to be canonicalized to X + X.
if (auto *C = isConstOrConstSplatFP(Op.getOperand(1)))
if (C->isExactlyValue(2.0) && Op.getOpcode() == ISD::FMUL)
break;
// Negate the Y if it is not expensive.
if (NegY) {
Cost = CostY;
return DAG.getNode(Opcode, DL, VT, X, NegY, Flags);
}
break;
}
case ISD::FMA:
case ISD::FMAD: {
if (!Options.NoSignedZerosFPMath && !Flags.hasNoSignedZeros())
break;
SDValue X = Op.getOperand(0), Y = Op.getOperand(1), Z = Op.getOperand(2);
NegatibleCost CostZ = NegatibleCost::Expensive;
SDValue NegZ =
getNegatedExpression(Z, DAG, LegalOps, OptForSize, CostZ, Depth);
// Give up if fail to negate the Z.
if (!NegZ)
break;
// fold (fneg (fma X, Y, Z)) -> (fma (fneg X), Y, (fneg Z))
NegatibleCost CostX = NegatibleCost::Expensive;
SDValue NegX =
getNegatedExpression(X, DAG, LegalOps, OptForSize, CostX, Depth);
// fold (fneg (fma X, Y, Z)) -> (fma X, (fneg Y), (fneg Z))
NegatibleCost CostY = NegatibleCost::Expensive;
SDValue NegY =
getNegatedExpression(Y, DAG, LegalOps, OptForSize, CostY, Depth);
// Negate the X if its cost is less or equal than Y.
if (NegX && (CostX <= CostY)) {
Cost = std::min(CostX, CostZ);
return DAG.getNode(Opcode, DL, VT, NegX, Y, NegZ, Flags);
}
// Negate the Y if it is not expensive.
if (NegY) {
Cost = std::min(CostY, CostZ);
return DAG.getNode(Opcode, DL, VT, X, NegY, NegZ, Flags);
}
break;
}
case ISD::FP_EXTEND:
case ISD::FSIN:
if (SDValue NegV = getNegatedExpression(Op.getOperand(0), DAG, LegalOps,
OptForSize, Cost, Depth))
return DAG.getNode(Opcode, DL, VT, NegV);
break;
case ISD::FP_ROUND:
if (SDValue NegV = getNegatedExpression(Op.getOperand(0), DAG, LegalOps,
OptForSize, Cost, Depth))
return DAG.getNode(ISD::FP_ROUND, DL, VT, NegV, Op.getOperand(1));
break;
}
return SDValue();
}
//===----------------------------------------------------------------------===//
// Legalization Utilities
//===----------------------------------------------------------------------===//
bool TargetLowering::expandMUL_LOHI(unsigned Opcode, EVT VT, SDLoc dl,
SDValue LHS, SDValue RHS,
SmallVectorImpl<SDValue> &Result,
EVT HiLoVT, SelectionDAG &DAG,
MulExpansionKind Kind, SDValue LL,
SDValue LH, SDValue RL, SDValue RH) const {
assert(Opcode == ISD::MUL || Opcode == ISD::UMUL_LOHI ||
Opcode == ISD::SMUL_LOHI);
bool HasMULHS = (Kind == MulExpansionKind::Always) ||
isOperationLegalOrCustom(ISD::MULHS, HiLoVT);
bool HasMULHU = (Kind == MulExpansionKind::Always) ||
isOperationLegalOrCustom(ISD::MULHU, HiLoVT);
bool HasSMUL_LOHI = (Kind == MulExpansionKind::Always) ||
isOperationLegalOrCustom(ISD::SMUL_LOHI, HiLoVT);
bool HasUMUL_LOHI = (Kind == MulExpansionKind::Always) ||
isOperationLegalOrCustom(ISD::UMUL_LOHI, HiLoVT);
if (!HasMULHU && !HasMULHS && !HasUMUL_LOHI && !HasSMUL_LOHI)
return false;
unsigned OuterBitSize = VT.getScalarSizeInBits();
unsigned InnerBitSize = HiLoVT.getScalarSizeInBits();
unsigned LHSSB = DAG.ComputeNumSignBits(LHS);
unsigned RHSSB = DAG.ComputeNumSignBits(RHS);
// LL, LH, RL, and RH must be either all NULL or all set to a value.
assert((LL.getNode() && LH.getNode() && RL.getNode() && RH.getNode()) ||
(!LL.getNode() && !LH.getNode() && !RL.getNode() && !RH.getNode()));
SDVTList VTs = DAG.getVTList(HiLoVT, HiLoVT);
auto MakeMUL_LOHI = [&](SDValue L, SDValue R, SDValue &Lo, SDValue &Hi,
bool Signed) -> bool {
if ((Signed && HasSMUL_LOHI) || (!Signed && HasUMUL_LOHI)) {
Lo = DAG.getNode(Signed ? ISD::SMUL_LOHI : ISD::UMUL_LOHI, dl, VTs, L, R);
Hi = SDValue(Lo.getNode(), 1);
return true;
}
if ((Signed && HasMULHS) || (!Signed && HasMULHU)) {
Lo = DAG.getNode(ISD::MUL, dl, HiLoVT, L, R);
Hi = DAG.getNode(Signed ? ISD::MULHS : ISD::MULHU, dl, HiLoVT, L, R);
return true;
}
return false;
};
SDValue Lo, Hi;
if (!LL.getNode() && !RL.getNode() &&
isOperationLegalOrCustom(ISD::TRUNCATE, HiLoVT)) {
LL = DAG.getNode(ISD::TRUNCATE, dl, HiLoVT, LHS);
RL = DAG.getNode(ISD::TRUNCATE, dl, HiLoVT, RHS);
}
if (!LL.getNode())
return false;
APInt HighMask = APInt::getHighBitsSet(OuterBitSize, InnerBitSize);
if (DAG.MaskedValueIsZero(LHS, HighMask) &&
DAG.MaskedValueIsZero(RHS, HighMask)) {
// The inputs are both zero-extended.
if (MakeMUL_LOHI(LL, RL, Lo, Hi, false)) {
Result.push_back(Lo);
Result.push_back(Hi);
if (Opcode != ISD::MUL) {
SDValue Zero = DAG.getConstant(0, dl, HiLoVT);
Result.push_back(Zero);
Result.push_back(Zero);
}
return true;
}
}
if (!VT.isVector() && Opcode == ISD::MUL && LHSSB > InnerBitSize &&
RHSSB > InnerBitSize) {
// The input values are both sign-extended.
// TODO non-MUL case?
if (MakeMUL_LOHI(LL, RL, Lo, Hi, true)) {
Result.push_back(Lo);
Result.push_back(Hi);
return true;
}
}
unsigned ShiftAmount = OuterBitSize - InnerBitSize;
EVT ShiftAmountTy = getShiftAmountTy(VT, DAG.getDataLayout());
if (APInt::getMaxValue(ShiftAmountTy.getSizeInBits()).ult(ShiftAmount)) {
// FIXME getShiftAmountTy does not always return a sensible result when VT
// is an illegal type, and so the type may be too small to fit the shift
// amount. Override it with i32. The shift will have to be legalized.
ShiftAmountTy = MVT::i32;
}
SDValue Shift = DAG.getConstant(ShiftAmount, dl, ShiftAmountTy);
if (!LH.getNode() && !RH.getNode() &&
isOperationLegalOrCustom(ISD::SRL, VT) &&
isOperationLegalOrCustom(ISD::TRUNCATE, HiLoVT)) {
LH = DAG.getNode(ISD::SRL, dl, VT, LHS, Shift);
LH = DAG.getNode(ISD::TRUNCATE, dl, HiLoVT, LH);
RH = DAG.getNode(ISD::SRL, dl, VT, RHS, Shift);
RH = DAG.getNode(ISD::TRUNCATE, dl, HiLoVT, RH);
}
if (!LH.getNode())
return false;
if (!MakeMUL_LOHI(LL, RL, Lo, Hi, false))
return false;
Result.push_back(Lo);
if (Opcode == ISD::MUL) {
RH = DAG.getNode(ISD::MUL, dl, HiLoVT, LL, RH);
LH = DAG.getNode(ISD::MUL, dl, HiLoVT, LH, RL);
Hi = DAG.getNode(ISD::ADD, dl, HiLoVT, Hi, RH);
Hi = DAG.getNode(ISD::ADD, dl, HiLoVT, Hi, LH);
Result.push_back(Hi);
return true;
}
// Compute the full width result.
auto Merge = [&](SDValue Lo, SDValue Hi) -> SDValue {
Lo = DAG.getNode(ISD::ZERO_EXTEND, dl, VT, Lo);
Hi = DAG.getNode(ISD::ZERO_EXTEND, dl, VT, Hi);
Hi = DAG.getNode(ISD::SHL, dl, VT, Hi, Shift);
return DAG.getNode(ISD::OR, dl, VT, Lo, Hi);
};
SDValue Next = DAG.getNode(ISD::ZERO_EXTEND, dl, VT, Hi);
if (!MakeMUL_LOHI(LL, RH, Lo, Hi, false))
return false;
// This is effectively the add part of a multiply-add of half-sized operands,
// so it cannot overflow.
Next = DAG.getNode(ISD::ADD, dl, VT, Next, Merge(Lo, Hi));
if (!MakeMUL_LOHI(LH, RL, Lo, Hi, false))
return false;
SDValue Zero = DAG.getConstant(0, dl, HiLoVT);
EVT BoolType = getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(), VT);
bool UseGlue = (isOperationLegalOrCustom(ISD::ADDC, VT) &&
isOperationLegalOrCustom(ISD::ADDE, VT));
if (UseGlue)
Next = DAG.getNode(ISD::ADDC, dl, DAG.getVTList(VT, MVT::Glue), Next,
Merge(Lo, Hi));
else
Next = DAG.getNode(ISD::ADDCARRY, dl, DAG.getVTList(VT, BoolType), Next,
Merge(Lo, Hi), DAG.getConstant(0, dl, BoolType));
SDValue Carry = Next.getValue(1);
Result.push_back(DAG.getNode(ISD::TRUNCATE, dl, HiLoVT, Next));
Next = DAG.getNode(ISD::SRL, dl, VT, Next, Shift);
if (!MakeMUL_LOHI(LH, RH, Lo, Hi, Opcode == ISD::SMUL_LOHI))
return false;
if (UseGlue)
Hi = DAG.getNode(ISD::ADDE, dl, DAG.getVTList(HiLoVT, MVT::Glue), Hi, Zero,
Carry);
else
Hi = DAG.getNode(ISD::ADDCARRY, dl, DAG.getVTList(HiLoVT, BoolType), Hi,
Zero, Carry);
Next = DAG.getNode(ISD::ADD, dl, VT, Next, Merge(Lo, Hi));
if (Opcode == ISD::SMUL_LOHI) {
SDValue NextSub = DAG.getNode(ISD::SUB, dl, VT, Next,
DAG.getNode(ISD::ZERO_EXTEND, dl, VT, RL));
Next = DAG.getSelectCC(dl, LH, Zero, NextSub, Next, ISD::SETLT);
NextSub = DAG.getNode(ISD::SUB, dl, VT, Next,
DAG.getNode(ISD::ZERO_EXTEND, dl, VT, LL));
Next = DAG.getSelectCC(dl, RH, Zero, NextSub, Next, ISD::SETLT);
}
Result.push_back(DAG.getNode(ISD::TRUNCATE, dl, HiLoVT, Next));
Next = DAG.getNode(ISD::SRL, dl, VT, Next, Shift);
Result.push_back(DAG.getNode(ISD::TRUNCATE, dl, HiLoVT, Next));
return true;
}
bool TargetLowering::expandMUL(SDNode *N, SDValue &Lo, SDValue &Hi, EVT HiLoVT,
SelectionDAG &DAG, MulExpansionKind Kind,
SDValue LL, SDValue LH, SDValue RL,
SDValue RH) const {
SmallVector<SDValue, 2> Result;
bool Ok = expandMUL_LOHI(N->getOpcode(), N->getValueType(0), N,
N->getOperand(0), N->getOperand(1), Result, HiLoVT,
DAG, Kind, LL, LH, RL, RH);
if (Ok) {
assert(Result.size() == 2);
Lo = Result[0];
Hi = Result[1];
}
return Ok;
}
// Check that (every element of) Z is undef or not an exact multiple of BW.
static bool isNonZeroModBitWidth(SDValue Z, unsigned BW) {
return ISD::matchUnaryPredicate(
Z,
[=](ConstantSDNode *C) { return !C || C->getAPIntValue().urem(BW) != 0; },
true);
}
bool TargetLowering::expandFunnelShift(SDNode *Node, SDValue &Result,
SelectionDAG &DAG) const {
EVT VT = Node->getValueType(0);
if (VT.isVector() && (!isOperationLegalOrCustom(ISD::SHL, VT) ||
!isOperationLegalOrCustom(ISD::SRL, VT) ||
!isOperationLegalOrCustom(ISD::SUB, VT) ||
!isOperationLegalOrCustomOrPromote(ISD::OR, VT)))
return false;
SDValue X = Node->getOperand(0);
SDValue Y = Node->getOperand(1);
SDValue Z = Node->getOperand(2);
unsigned BW = VT.getScalarSizeInBits();
bool IsFSHL = Node->getOpcode() == ISD::FSHL;
SDLoc DL(SDValue(Node, 0));
EVT ShVT = Z.getValueType();
SDValue ShX, ShY;
SDValue ShAmt, InvShAmt;
if (isNonZeroModBitWidth(Z, BW)) {
// fshl: X << C | Y >> (BW - C)
// fshr: X << (BW - C) | Y >> C
// where C = Z % BW is not zero
SDValue BitWidthC = DAG.getConstant(BW, DL, ShVT);
ShAmt = DAG.getNode(ISD::UREM, DL, ShVT, Z, BitWidthC);
InvShAmt = DAG.getNode(ISD::SUB, DL, ShVT, BitWidthC, ShAmt);
ShX = DAG.getNode(ISD::SHL, DL, VT, X, IsFSHL ? ShAmt : InvShAmt);
ShY = DAG.getNode(ISD::SRL, DL, VT, Y, IsFSHL ? InvShAmt : ShAmt);
} else {
// fshl: X << (Z % BW) | Y >> 1 >> (BW - 1 - (Z % BW))
// fshr: X << 1 << (BW - 1 - (Z % BW)) | Y >> (Z % BW)
SDValue Mask = DAG.getConstant(BW - 1, DL, ShVT);
if (isPowerOf2_32(BW)) {
// Z % BW -> Z & (BW - 1)
ShAmt = DAG.getNode(ISD::AND, DL, ShVT, Z, Mask);
// (BW - 1) - (Z % BW) -> ~Z & (BW - 1)
InvShAmt = DAG.getNode(ISD::AND, DL, ShVT, DAG.getNOT(DL, Z, ShVT), Mask);
} else {
SDValue BitWidthC = DAG.getConstant(BW, DL, ShVT);
ShAmt = DAG.getNode(ISD::UREM, DL, ShVT, Z, BitWidthC);
InvShAmt = DAG.getNode(ISD::SUB, DL, ShVT, Mask, ShAmt);
}
SDValue One = DAG.getConstant(1, DL, ShVT);
if (IsFSHL) {
ShX = DAG.getNode(ISD::SHL, DL, VT, X, ShAmt);
SDValue ShY1 = DAG.getNode(ISD::SRL, DL, VT, Y, One);
ShY = DAG.getNode(ISD::SRL, DL, VT, ShY1, InvShAmt);
} else {
SDValue ShX1 = DAG.getNode(ISD::SHL, DL, VT, X, One);
ShX = DAG.getNode(ISD::SHL, DL, VT, ShX1, InvShAmt);
ShY = DAG.getNode(ISD::SRL, DL, VT, Y, ShAmt);
}
}
Result = DAG.getNode(ISD::OR, DL, VT, ShX, ShY);
return true;
}
// TODO: Merge with expandFunnelShift.
bool TargetLowering::expandROT(SDNode *Node, SDValue &Result,
SelectionDAG &DAG) const {
EVT VT = Node->getValueType(0);
unsigned EltSizeInBits = VT.getScalarSizeInBits();
bool IsLeft = Node->getOpcode() == ISD::ROTL;
SDValue Op0 = Node->getOperand(0);
SDValue Op1 = Node->getOperand(1);
SDLoc DL(SDValue(Node, 0));
EVT ShVT = Op1.getValueType();
SDValue Zero = DAG.getConstant(0, DL, ShVT);
assert(isPowerOf2_32(EltSizeInBits) && EltSizeInBits > 1 &&
"Expecting the type bitwidth to be a power of 2");
// If a rotate in the other direction is supported, use it.
unsigned RevRot = IsLeft ? ISD::ROTR : ISD::ROTL;
if (isOperationLegalOrCustom(RevRot, VT)) {
SDValue Sub = DAG.getNode(ISD::SUB, DL, ShVT, Zero, Op1);
Result = DAG.getNode(RevRot, DL, VT, Op0, Sub);
return true;
}
if (VT.isVector() && (!isOperationLegalOrCustom(ISD::SHL, VT) ||
!isOperationLegalOrCustom(ISD::SRL, VT) ||
!isOperationLegalOrCustom(ISD::SUB, VT) ||
!isOperationLegalOrCustomOrPromote(ISD::OR, VT) ||
!isOperationLegalOrCustomOrPromote(ISD::AND, VT)))
return false;
// Otherwise,
// (rotl x, c) -> (or (shl x, (and c, w-1)), (srl x, (and -c, w-1)))
// (rotr x, c) -> (or (srl x, (and c, w-1)), (shl x, (and -c, w-1)))
//
unsigned ShOpc = IsLeft ? ISD::SHL : ISD::SRL;
unsigned HsOpc = IsLeft ? ISD::SRL : ISD::SHL;
SDValue BitWidthMinusOneC = DAG.getConstant(EltSizeInBits - 1, DL, ShVT);
SDValue NegOp1 = DAG.getNode(ISD::SUB, DL, ShVT, Zero, Op1);
SDValue And0 = DAG.getNode(ISD::AND, DL, ShVT, Op1, BitWidthMinusOneC);
SDValue And1 = DAG.getNode(ISD::AND, DL, ShVT, NegOp1, BitWidthMinusOneC);
Result = DAG.getNode(ISD::OR, DL, VT, DAG.getNode(ShOpc, DL, VT, Op0, And0),
DAG.getNode(HsOpc, DL, VT, Op0, And1));
return true;
}
bool TargetLowering::expandFP_TO_SINT(SDNode *Node, SDValue &Result,
SelectionDAG &DAG) const {
unsigned OpNo = Node->isStrictFPOpcode() ? 1 : 0;
SDValue Src = Node->getOperand(OpNo);
EVT SrcVT = Src.getValueType();
EVT DstVT = Node->getValueType(0);
SDLoc dl(SDValue(Node, 0));
// FIXME: Only f32 to i64 conversions are supported.
if (SrcVT != MVT::f32 || DstVT != MVT::i64)
return false;
if (Node->isStrictFPOpcode())
// When a NaN is converted to an integer a trap is allowed. We can't
// use this expansion here because it would eliminate that trap. Other
// traps are also allowed and cannot be eliminated. See
// IEEE 754-2008 sec 5.8.
return false;
// Expand f32 -> i64 conversion
// This algorithm comes from compiler-rt's implementation of fixsfdi:
// https://github.com/llvm/llvm-project/blob/master/compiler-rt/lib/builtins/fixsfdi.c
unsigned SrcEltBits = SrcVT.getScalarSizeInBits();
EVT IntVT = SrcVT.changeTypeToInteger();
EVT IntShVT = getShiftAmountTy(IntVT, DAG.getDataLayout());
SDValue ExponentMask = DAG.getConstant(0x7F800000, dl, IntVT);
SDValue ExponentLoBit = DAG.getConstant(23, dl, IntVT);
SDValue Bias = DAG.getConstant(127, dl, IntVT);
SDValue SignMask = DAG.getConstant(APInt::getSignMask(SrcEltBits), dl, IntVT);
SDValue SignLowBit = DAG.getConstant(SrcEltBits - 1, dl, IntVT);
SDValue MantissaMask = DAG.getConstant(0x007FFFFF, dl, IntVT);
SDValue Bits = DAG.getNode(ISD::BITCAST, dl, IntVT, Src);
SDValue ExponentBits = DAG.getNode(
ISD::SRL, dl, IntVT, DAG.getNode(ISD::AND, dl, IntVT, Bits, ExponentMask),
DAG.getZExtOrTrunc(ExponentLoBit, dl, IntShVT));
SDValue Exponent = DAG.getNode(ISD::SUB, dl, IntVT, ExponentBits, Bias);
SDValue Sign = DAG.getNode(ISD::SRA, dl, IntVT,
DAG.getNode(ISD::AND, dl, IntVT, Bits, SignMask),
DAG.getZExtOrTrunc(SignLowBit, dl, IntShVT));
Sign = DAG.getSExtOrTrunc(Sign, dl, DstVT);
SDValue R = DAG.getNode(ISD::OR, dl, IntVT,
DAG.getNode(ISD::AND, dl, IntVT, Bits, MantissaMask),
DAG.getConstant(0x00800000, dl, IntVT));
R = DAG.getZExtOrTrunc(R, dl, DstVT);
R = DAG.getSelectCC(
dl, Exponent, ExponentLoBit,
DAG.getNode(ISD::SHL, dl, DstVT, R,
DAG.getZExtOrTrunc(
DAG.getNode(ISD::SUB, dl, IntVT, Exponent, ExponentLoBit),
dl, IntShVT)),
DAG.getNode(ISD::SRL, dl, DstVT, R,
DAG.getZExtOrTrunc(
DAG.getNode(ISD::SUB, dl, IntVT, ExponentLoBit, Exponent),
dl, IntShVT)),
ISD::SETGT);
SDValue Ret = DAG.getNode(ISD::SUB, dl, DstVT,
DAG.getNode(ISD::XOR, dl, DstVT, R, Sign), Sign);
Result = DAG.getSelectCC(dl, Exponent, DAG.getConstant(0, dl, IntVT),
DAG.getConstant(0, dl, DstVT), Ret, ISD::SETLT);
return true;
}
bool TargetLowering::expandFP_TO_UINT(SDNode *Node, SDValue &Result,
SDValue &Chain,
SelectionDAG &DAG) const {
SDLoc dl(SDValue(Node, 0));
unsigned OpNo = Node->isStrictFPOpcode() ? 1 : 0;
SDValue Src = Node->getOperand(OpNo);
EVT SrcVT = Src.getValueType();
EVT DstVT = Node->getValueType(0);
EVT SetCCVT =
getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(), SrcVT);
EVT DstSetCCVT =
getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(), DstVT);
// Only expand vector types if we have the appropriate vector bit operations.
unsigned SIntOpcode = Node->isStrictFPOpcode() ? ISD::STRICT_FP_TO_SINT :
ISD::FP_TO_SINT;
if (DstVT.isVector() && (!isOperationLegalOrCustom(SIntOpcode, DstVT) ||
!isOperationLegalOrCustomOrPromote(ISD::XOR, SrcVT)))
return false;
// If the maximum float value is smaller then the signed integer range,
// the destination signmask can't be represented by the float, so we can
// just use FP_TO_SINT directly.
const fltSemantics &APFSem = DAG.EVTToAPFloatSemantics(SrcVT);
APFloat APF(APFSem, APInt::getNullValue(SrcVT.getScalarSizeInBits()));
APInt SignMask = APInt::getSignMask(DstVT.getScalarSizeInBits());
if (APFloat::opOverflow &
APF.convertFromAPInt(SignMask, false, APFloat::rmNearestTiesToEven)) {
if (Node->isStrictFPOpcode()) {
Result = DAG.getNode(ISD::STRICT_FP_TO_SINT, dl, { DstVT, MVT::Other },
{ Node->getOperand(0), Src });
Chain = Result.getValue(1);
} else
Result = DAG.getNode(ISD::FP_TO_SINT, dl, DstVT, Src);
return true;
}
SDValue Cst = DAG.getConstantFP(APF, dl, SrcVT);
SDValue Sel;
if (Node->isStrictFPOpcode()) {
Sel = DAG.getSetCC(dl, SetCCVT, Src, Cst, ISD::SETLT,
Node->getOperand(0), /*IsSignaling*/ true);
Chain = Sel.getValue(1);
} else {
Sel = DAG.getSetCC(dl, SetCCVT, Src, Cst, ISD::SETLT);
}
bool Strict = Node->isStrictFPOpcode() ||
shouldUseStrictFP_TO_INT(SrcVT, DstVT, /*IsSigned*/ false);
if (Strict) {
// Expand based on maximum range of FP_TO_SINT, if the value exceeds the
// signmask then offset (the result of which should be fully representable).
// Sel = Src < 0x8000000000000000
// FltOfs = select Sel, 0, 0x8000000000000000
// IntOfs = select Sel, 0, 0x8000000000000000
// Result = fp_to_sint(Src - FltOfs) ^ IntOfs
// TODO: Should any fast-math-flags be set for the FSUB?
SDValue FltOfs = DAG.getSelect(dl, SrcVT, Sel,
DAG.getConstantFP(0.0, dl, SrcVT), Cst);
Sel = DAG.getBoolExtOrTrunc(Sel, dl, DstSetCCVT, DstVT);
SDValue IntOfs = DAG.getSelect(dl, DstVT, Sel,
DAG.getConstant(0, dl, DstVT),
DAG.getConstant(SignMask, dl, DstVT));
SDValue SInt;
if (Node->isStrictFPOpcode()) {
SDValue Val = DAG.getNode(ISD::STRICT_FSUB, dl, { SrcVT, MVT::Other },
{ Chain, Src, FltOfs });
SInt = DAG.getNode(ISD::STRICT_FP_TO_SINT, dl, { DstVT, MVT::Other },
{ Val.getValue(1), Val });
Chain = SInt.getValue(1);
} else {
SDValue Val = DAG.getNode(ISD::FSUB, dl, SrcVT, Src, FltOfs);
SInt = DAG.getNode(ISD::FP_TO_SINT, dl, DstVT, Val);
}
Result = DAG.getNode(ISD::XOR, dl, DstVT, SInt, IntOfs);
} else {
// Expand based on maximum range of FP_TO_SINT:
// True = fp_to_sint(Src)
// False = 0x8000000000000000 + fp_to_sint(Src - 0x8000000000000000)
// Result = select (Src < 0x8000000000000000), True, False
SDValue True = DAG.getNode(ISD::FP_TO_SINT, dl, DstVT, Src);
// TODO: Should any fast-math-flags be set for the FSUB?
SDValue False = DAG.getNode(ISD::FP_TO_SINT, dl, DstVT,
DAG.getNode(ISD::FSUB, dl, SrcVT, Src, Cst));
False = DAG.getNode(ISD::XOR, dl, DstVT, False,
DAG.getConstant(SignMask, dl, DstVT));
Sel = DAG.getBoolExtOrTrunc(Sel, dl, DstSetCCVT, DstVT);
Result = DAG.getSelect(dl, DstVT, Sel, True, False);
}
return true;
}
bool TargetLowering::expandUINT_TO_FP(SDNode *Node, SDValue &Result,
SDValue &Chain,
SelectionDAG &DAG) const {
unsigned OpNo = Node->isStrictFPOpcode() ? 1 : 0;
SDValue Src = Node->getOperand(OpNo);
EVT SrcVT = Src.getValueType();
EVT DstVT = Node->getValueType(0);
if (SrcVT.getScalarType() != MVT::i64 || DstVT.getScalarType() != MVT::f64)
return false;
// Only expand vector types if we have the appropriate vector bit operations.
if (SrcVT.isVector() && (!isOperationLegalOrCustom(ISD::SRL, SrcVT) ||
!isOperationLegalOrCustom(ISD::FADD, DstVT) ||
!isOperationLegalOrCustom(ISD::FSUB, DstVT) ||
!isOperationLegalOrCustomOrPromote(ISD::OR, SrcVT) ||
!isOperationLegalOrCustomOrPromote(ISD::AND, SrcVT)))
return false;
SDLoc dl(SDValue(Node, 0));
EVT ShiftVT = getShiftAmountTy(SrcVT, DAG.getDataLayout());
// Implementation of unsigned i64 to f64 following the algorithm in
// __floatundidf in compiler_rt. This implementation has the advantage
// of performing rounding correctly, both in the default rounding mode
// and in all alternate rounding modes.
SDValue TwoP52 = DAG.getConstant(UINT64_C(0x4330000000000000), dl, SrcVT);
SDValue TwoP84PlusTwoP52 = DAG.getConstantFP(
BitsToDouble(UINT64_C(0x4530000000100000)), dl, DstVT);
SDValue TwoP84 = DAG.getConstant(UINT64_C(0x4530000000000000), dl, SrcVT);
SDValue LoMask = DAG.getConstant(UINT64_C(0x00000000FFFFFFFF), dl, SrcVT);
SDValue HiShift = DAG.getConstant(32, dl, ShiftVT);
SDValue Lo = DAG.getNode(ISD::AND, dl, SrcVT, Src, LoMask);
SDValue Hi = DAG.getNode(ISD::SRL, dl, SrcVT, Src, HiShift);
SDValue LoOr = DAG.getNode(ISD::OR, dl, SrcVT, Lo, TwoP52);
SDValue HiOr = DAG.getNode(ISD::OR, dl, SrcVT, Hi, TwoP84);
SDValue LoFlt = DAG.getBitcast(DstVT, LoOr);
SDValue HiFlt = DAG.getBitcast(DstVT, HiOr);
if (Node->isStrictFPOpcode()) {
SDValue HiSub =
DAG.getNode(ISD::STRICT_FSUB, dl, {DstVT, MVT::Other},
{Node->getOperand(0), HiFlt, TwoP84PlusTwoP52});
Result = DAG.getNode(ISD::STRICT_FADD, dl, {DstVT, MVT::Other},
{HiSub.getValue(1), LoFlt, HiSub});
Chain = Result.getValue(1);
} else {
SDValue HiSub =
DAG.getNode(ISD::FSUB, dl, DstVT, HiFlt, TwoP84PlusTwoP52);
Result = DAG.getNode(ISD::FADD, dl, DstVT, LoFlt, HiSub);
}
return true;
}
SDValue TargetLowering::expandFMINNUM_FMAXNUM(SDNode *Node,
SelectionDAG &DAG) const {
SDLoc dl(Node);
unsigned NewOp = Node->getOpcode() == ISD::FMINNUM ?
ISD::FMINNUM_IEEE : ISD::FMAXNUM_IEEE;
EVT VT = Node->getValueType(0);
if (isOperationLegalOrCustom(NewOp, VT)) {
SDValue Quiet0 = Node->getOperand(0);
SDValue Quiet1 = Node->getOperand(1);
if (!Node->getFlags().hasNoNaNs()) {
// Insert canonicalizes if it's possible we need to quiet to get correct
// sNaN behavior.
if (!DAG.isKnownNeverSNaN(Quiet0)) {
Quiet0 = DAG.getNode(ISD::FCANONICALIZE, dl, VT, Quiet0,
Node->getFlags());
}
if (!DAG.isKnownNeverSNaN(Quiet1)) {
Quiet1 = DAG.getNode(ISD::FCANONICALIZE, dl, VT, Quiet1,
Node->getFlags());
}
}
return DAG.getNode(NewOp, dl, VT, Quiet0, Quiet1, Node->getFlags());
}
// If the target has FMINIMUM/FMAXIMUM but not FMINNUM/FMAXNUM use that
// instead if there are no NaNs.
if (Node->getFlags().hasNoNaNs()) {
unsigned IEEE2018Op =
Node->getOpcode() == ISD::FMINNUM ? ISD::FMINIMUM : ISD::FMAXIMUM;
if (isOperationLegalOrCustom(IEEE2018Op, VT)) {
return DAG.getNode(IEEE2018Op, dl, VT, Node->getOperand(0),
Node->getOperand(1), Node->getFlags());
}
}
// If none of the above worked, but there are no NaNs, then expand to
// a compare/select sequence. This is required for correctness since
// InstCombine might have canonicalized a fcmp+select sequence to a
// FMINNUM/FMAXNUM node. If we were to fall through to the default
// expansion to libcall, we might introduce a link-time dependency
// on libm into a file that originally did not have one.
if (Node->getFlags().hasNoNaNs()) {
ISD::CondCode Pred =
Node->getOpcode() == ISD::FMINNUM ? ISD::SETLT : ISD::SETGT;
SDValue Op1 = Node->getOperand(0);
SDValue Op2 = Node->getOperand(1);
SDValue SelCC = DAG.getSelectCC(dl, Op1, Op2, Op1, Op2, Pred);
// Copy FMF flags, but always set the no-signed-zeros flag
// as this is implied by the FMINNUM/FMAXNUM semantics.
SDNodeFlags Flags = Node->getFlags();
Flags.setNoSignedZeros(true);
SelCC->setFlags(Flags);
return SelCC;
}
return SDValue();
}
bool TargetLowering::expandCTPOP(SDNode *Node, SDValue &Result,
SelectionDAG &DAG) const {
SDLoc dl(Node);
EVT VT = Node->getValueType(0);
EVT ShVT = getShiftAmountTy(VT, DAG.getDataLayout());
SDValue Op = Node->getOperand(0);
unsigned Len = VT.getScalarSizeInBits();
assert(VT.isInteger() && "CTPOP not implemented for this type.");
// TODO: Add support for irregular type lengths.
if (!(Len <= 128 && Len % 8 == 0))
return false;
// Only expand vector types if we have the appropriate vector bit operations.
if (VT.isVector() && (!isOperationLegalOrCustom(ISD::ADD, VT) ||
!isOperationLegalOrCustom(ISD::SUB, VT) ||
!isOperationLegalOrCustom(ISD::SRL, VT) ||
(Len != 8 && !isOperationLegalOrCustom(ISD::MUL, VT)) ||
!isOperationLegalOrCustomOrPromote(ISD::AND, VT)))
return false;
// This is the "best" algorithm from
// http://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetParallel
SDValue Mask55 =
DAG.getConstant(APInt::getSplat(Len, APInt(8, 0x55)), dl, VT);
SDValue Mask33 =
DAG.getConstant(APInt::getSplat(Len, APInt(8, 0x33)), dl, VT);
SDValue Mask0F =
DAG.getConstant(APInt::getSplat(Len, APInt(8, 0x0F)), dl, VT);
SDValue Mask01 =
DAG.getConstant(APInt::getSplat(Len, APInt(8, 0x01)), dl, VT);
// v = v - ((v >> 1) & 0x55555555...)
Op = DAG.getNode(ISD::SUB, dl, VT, Op,
DAG.getNode(ISD::AND, dl, VT,
DAG.getNode(ISD::SRL, dl, VT, Op,
DAG.getConstant(1, dl, ShVT)),
Mask55));
// v = (v & 0x33333333...) + ((v >> 2) & 0x33333333...)
Op = DAG.getNode(ISD::ADD, dl, VT, DAG.getNode(ISD::AND, dl, VT, Op, Mask33),
DAG.getNode(ISD::AND, dl, VT,
DAG.getNode(ISD::SRL, dl, VT, Op,
DAG.getConstant(2, dl, ShVT)),
Mask33));
// v = (v + (v >> 4)) & 0x0F0F0F0F...
Op = DAG.getNode(ISD::AND, dl, VT,
DAG.getNode(ISD::ADD, dl, VT, Op,
DAG.getNode(ISD::SRL, dl, VT, Op,
DAG.getConstant(4, dl, ShVT))),
Mask0F);
// v = (v * 0x01010101...) >> (Len - 8)
if (Len > 8)
Op =
DAG.getNode(ISD::SRL, dl, VT, DAG.getNode(ISD::MUL, dl, VT, Op, Mask01),
DAG.getConstant(Len - 8, dl, ShVT));
Result = Op;
return true;
}
bool TargetLowering::expandCTLZ(SDNode *Node, SDValue &Result,
SelectionDAG &DAG) const {
SDLoc dl(Node);
EVT VT = Node->getValueType(0);
EVT ShVT = getShiftAmountTy(VT, DAG.getDataLayout());
SDValue Op = Node->getOperand(0);
unsigned NumBitsPerElt = VT.getScalarSizeInBits();
// If the non-ZERO_UNDEF version is supported we can use that instead.
if (Node->getOpcode() == ISD::CTLZ_ZERO_UNDEF &&
isOperationLegalOrCustom(ISD::CTLZ, VT)) {
Result = DAG.getNode(ISD::CTLZ, dl, VT, Op);
return true;
}
// If the ZERO_UNDEF version is supported use that and handle the zero case.
if (isOperationLegalOrCustom(ISD::CTLZ_ZERO_UNDEF, VT)) {
EVT SetCCVT =
getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(), VT);
SDValue CTLZ = DAG.getNode(ISD::CTLZ_ZERO_UNDEF, dl, VT, Op);
SDValue Zero = DAG.getConstant(0, dl, VT);
SDValue SrcIsZero = DAG.getSetCC(dl, SetCCVT, Op, Zero, ISD::SETEQ);
Result = DAG.getNode(ISD::SELECT, dl, VT, SrcIsZero,
DAG.getConstant(NumBitsPerElt, dl, VT), CTLZ);
return true;
}
// Only expand vector types if we have the appropriate vector bit operations.
if (VT.isVector() && (!isPowerOf2_32(NumBitsPerElt) ||
!isOperationLegalOrCustom(ISD::CTPOP, VT) ||
!isOperationLegalOrCustom(ISD::SRL, VT) ||
!isOperationLegalOrCustomOrPromote(ISD::OR, VT)))
return false;
// for now, we do this:
// x = x | (x >> 1);
// x = x | (x >> 2);
// ...
// x = x | (x >>16);
// x = x | (x >>32); // for 64-bit input
// return popcount(~x);
//
// Ref: "Hacker's Delight" by Henry Warren
for (unsigned i = 0; (1U << i) <= (NumBitsPerElt / 2); ++i) {
SDValue Tmp = DAG.getConstant(1ULL << i, dl, ShVT);
Op = DAG.getNode(ISD::OR, dl, VT, Op,
DAG.getNode(ISD::SRL, dl, VT, Op, Tmp));
}
Op = DAG.getNOT(dl, Op, VT);
Result = DAG.getNode(ISD::CTPOP, dl, VT, Op);
return true;
}
bool TargetLowering::expandCTTZ(SDNode *Node, SDValue &Result,
SelectionDAG &DAG) const {
SDLoc dl(Node);
EVT VT = Node->getValueType(0);
SDValue Op = Node->getOperand(0);
unsigned NumBitsPerElt = VT.getScalarSizeInBits();
// If the non-ZERO_UNDEF version is supported we can use that instead.
if (Node->getOpcode() == ISD::CTTZ_ZERO_UNDEF &&
isOperationLegalOrCustom(ISD::CTTZ, VT)) {
Result = DAG.getNode(ISD::CTTZ, dl, VT, Op);
return true;
}
// If the ZERO_UNDEF version is supported use that and handle the zero case.
if (isOperationLegalOrCustom(ISD::CTTZ_ZERO_UNDEF, VT)) {
EVT SetCCVT =
getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(), VT);
SDValue CTTZ = DAG.getNode(ISD::CTTZ_ZERO_UNDEF, dl, VT, Op);
SDValue Zero = DAG.getConstant(0, dl, VT);
SDValue SrcIsZero = DAG.getSetCC(dl, SetCCVT, Op, Zero, ISD::SETEQ);
Result = DAG.getNode(ISD::SELECT, dl, VT, SrcIsZero,
DAG.getConstant(NumBitsPerElt, dl, VT), CTTZ);
return true;
}
// Only expand vector types if we have the appropriate vector bit operations.
if (VT.isVector() && (!isPowerOf2_32(NumBitsPerElt) ||
(!isOperationLegalOrCustom(ISD::CTPOP, VT) &&
!isOperationLegalOrCustom(ISD::CTLZ, VT)) ||
!isOperationLegalOrCustom(ISD::SUB, VT) ||
!isOperationLegalOrCustomOrPromote(ISD::AND, VT) ||
!isOperationLegalOrCustomOrPromote(ISD::XOR, VT)))
return false;
// for now, we use: { return popcount(~x & (x - 1)); }
// unless the target has ctlz but not ctpop, in which case we use:
// { return 32 - nlz(~x & (x-1)); }
// Ref: "Hacker's Delight" by Henry Warren
SDValue Tmp = DAG.getNode(
ISD::AND, dl, VT, DAG.getNOT(dl, Op, VT),
DAG.getNode(ISD::SUB, dl, VT, Op, DAG.getConstant(1, dl, VT)));
// If ISD::CTLZ is legal and CTPOP isn't, then do that instead.
if (isOperationLegal(ISD::CTLZ, VT) && !isOperationLegal(ISD::CTPOP, VT)) {
Result =
DAG.getNode(ISD::SUB, dl, VT, DAG.getConstant(NumBitsPerElt, dl, VT),
DAG.getNode(ISD::CTLZ, dl, VT, Tmp));
return true;
}
Result = DAG.getNode(ISD::CTPOP, dl, VT, Tmp);
return true;
}
bool TargetLowering::expandABS(SDNode *N, SDValue &Result,
SelectionDAG &DAG) const {
SDLoc dl(N);
EVT VT = N->getValueType(0);
EVT ShVT = getShiftAmountTy(VT, DAG.getDataLayout());
SDValue Op = N->getOperand(0);
// Only expand vector types if we have the appropriate vector operations.
if (VT.isVector() && (!isOperationLegalOrCustom(ISD::SRA, VT) ||
!isOperationLegalOrCustom(ISD::ADD, VT) ||
!isOperationLegalOrCustomOrPromote(ISD::XOR, VT)))
return false;
SDValue Shift =
DAG.getNode(ISD::SRA, dl, VT, Op,
DAG.getConstant(VT.getScalarSizeInBits() - 1, dl, ShVT));
SDValue Add = DAG.getNode(ISD::ADD, dl, VT, Op, Shift);
Result = DAG.getNode(ISD::XOR, dl, VT, Add, Shift);
return true;
}
std::pair<SDValue, SDValue>
TargetLowering::scalarizeVectorLoad(LoadSDNode *LD,
SelectionDAG &DAG) const {
SDLoc SL(LD);
SDValue Chain = LD->getChain();
SDValue BasePTR = LD->getBasePtr();
EVT SrcVT = LD->getMemoryVT();
EVT DstVT = LD->getValueType(0);
ISD::LoadExtType ExtType = LD->getExtensionType();
unsigned NumElem = SrcVT.getVectorNumElements();
EVT SrcEltVT = SrcVT.getScalarType();
EVT DstEltVT = DstVT.getScalarType();
// A vector must always be stored in memory as-is, i.e. without any padding
// between the elements, since various code depend on it, e.g. in the
// handling of a bitcast of a vector type to int, which may be done with a
// vector store followed by an integer load. A vector that does not have
// elements that are byte-sized must therefore be stored as an integer
// built out of the extracted vector elements.
if (!SrcEltVT.isByteSized()) {
unsigned NumLoadBits = SrcVT.getStoreSizeInBits();
EVT LoadVT = EVT::getIntegerVT(*DAG.getContext(), NumLoadBits);
unsigned NumSrcBits = SrcVT.getSizeInBits();
EVT SrcIntVT = EVT::getIntegerVT(*DAG.getContext(), NumSrcBits);
unsigned SrcEltBits = SrcEltVT.getSizeInBits();
SDValue SrcEltBitMask = DAG.getConstant(
APInt::getLowBitsSet(NumLoadBits, SrcEltBits), SL, LoadVT);
// Load the whole vector and avoid masking off the top bits as it makes
// the codegen worse.
SDValue Load =
DAG.getExtLoad(ISD::EXTLOAD, SL, LoadVT, Chain, BasePTR,
LD->getPointerInfo(), SrcIntVT, LD->getAlignment(),
LD->getMemOperand()->getFlags(), LD->getAAInfo());
SmallVector<SDValue, 8> Vals;
for (unsigned Idx = 0; Idx < NumElem; ++Idx) {
unsigned ShiftIntoIdx =
(DAG.getDataLayout().isBigEndian() ? (NumElem - 1) - Idx : Idx);
SDValue ShiftAmount =
DAG.getShiftAmountConstant(ShiftIntoIdx * SrcEltVT.getSizeInBits(),
LoadVT, SL, /*LegalTypes=*/false);
SDValue ShiftedElt = DAG.getNode(ISD::SRL, SL, LoadVT, Load, ShiftAmount);
SDValue Elt =
DAG.getNode(ISD::AND, SL, LoadVT, ShiftedElt, SrcEltBitMask);
SDValue Scalar = DAG.getNode(ISD::TRUNCATE, SL, SrcEltVT, Elt);
if (ExtType != ISD::NON_EXTLOAD) {
unsigned ExtendOp = ISD::getExtForLoadExtType(false, ExtType);
Scalar = DAG.getNode(ExtendOp, SL, DstEltVT, Scalar);
}
Vals.push_back(Scalar);
}
SDValue Value = DAG.getBuildVector(DstVT, SL, Vals);
return std::make_pair(Value, Load.getValue(1));
}
unsigned Stride = SrcEltVT.getSizeInBits() / 8;
assert(SrcEltVT.isByteSized());
SmallVector<SDValue, 8> Vals;
SmallVector<SDValue, 8> LoadChains;
for (unsigned Idx = 0; Idx < NumElem; ++Idx) {
SDValue ScalarLoad =
DAG.getExtLoad(ExtType, SL, DstEltVT, Chain, BasePTR,
LD->getPointerInfo().getWithOffset(Idx * Stride),
SrcEltVT, MinAlign(LD->getAlignment(), Idx * Stride),
LD->getMemOperand()->getFlags(), LD->getAAInfo());
BasePTR = DAG.getObjectPtrOffset(SL, BasePTR, Stride);
Vals.push_back(ScalarLoad.getValue(0));
LoadChains.push_back(ScalarLoad.getValue(1));
}
SDValue NewChain = DAG.getNode(ISD::TokenFactor, SL, MVT::Other, LoadChains);
SDValue Value = DAG.getBuildVector(DstVT, SL, Vals);
return std::make_pair(Value, NewChain);
}
SDValue TargetLowering::scalarizeVectorStore(StoreSDNode *ST,
SelectionDAG &DAG) const {
SDLoc SL(ST);
SDValue Chain = ST->getChain();
SDValue BasePtr = ST->getBasePtr();
SDValue Value = ST->getValue();
EVT StVT = ST->getMemoryVT();
// The type of the data we want to save
EVT RegVT = Value.getValueType();
EVT RegSclVT = RegVT.getScalarType();
// The type of data as saved in memory.
EVT MemSclVT = StVT.getScalarType();
unsigned NumElem = StVT.getVectorNumElements();
// A vector must always be stored in memory as-is, i.e. without any padding
// between the elements, since various code depend on it, e.g. in the
// handling of a bitcast of a vector type to int, which may be done with a
// vector store followed by an integer load. A vector that does not have
// elements that are byte-sized must therefore be stored as an integer
// built out of the extracted vector elements.
if (!MemSclVT.isByteSized()) {
unsigned NumBits = StVT.getSizeInBits();
EVT IntVT = EVT::getIntegerVT(*DAG.getContext(), NumBits);
SDValue CurrVal = DAG.getConstant(0, SL, IntVT);
for (unsigned Idx = 0; Idx < NumElem; ++Idx) {
SDValue Elt = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, SL, RegSclVT, Value,
DAG.getVectorIdxConstant(Idx, SL));
SDValue Trunc = DAG.getNode(ISD::TRUNCATE, SL, MemSclVT, Elt);
SDValue ExtElt = DAG.getNode(ISD::ZERO_EXTEND, SL, IntVT, Trunc);
unsigned ShiftIntoIdx =
(DAG.getDataLayout().isBigEndian() ? (NumElem - 1) - Idx : Idx);
SDValue ShiftAmount =
DAG.getConstant(ShiftIntoIdx * MemSclVT.getSizeInBits(), SL, IntVT);
SDValue ShiftedElt =
DAG.getNode(ISD::SHL, SL, IntVT, ExtElt, ShiftAmount);
CurrVal = DAG.getNode(ISD::OR, SL, IntVT, CurrVal, ShiftedElt);
}
return DAG.getStore(Chain, SL, CurrVal, BasePtr, ST->getPointerInfo(),
ST->getAlignment(), ST->getMemOperand()->getFlags(),
ST->getAAInfo());
}
// Store Stride in bytes
unsigned Stride = MemSclVT.getSizeInBits() / 8;
assert(Stride && "Zero stride!");
// Extract each of the elements from the original vector and save them into
// memory individually.
SmallVector<SDValue, 8> Stores;
for (unsigned Idx = 0; Idx < NumElem; ++Idx) {
SDValue Elt = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, SL, RegSclVT, Value,
DAG.getVectorIdxConstant(Idx, SL));
SDValue Ptr = DAG.getObjectPtrOffset(SL, BasePtr, Idx * Stride);
// This scalar TruncStore may be illegal, but we legalize it later.
SDValue Store = DAG.getTruncStore(
Chain, SL, Elt, Ptr, ST->getPointerInfo().getWithOffset(Idx * Stride),
MemSclVT, MinAlign(ST->getAlignment(), Idx * Stride),
ST->getMemOperand()->getFlags(), ST->getAAInfo());
Stores.push_back(Store);
}
return DAG.getNode(ISD::TokenFactor, SL, MVT::Other, Stores);
}
std::pair<SDValue, SDValue>
TargetLowering::expandUnalignedLoad(LoadSDNode *LD, SelectionDAG &DAG) const {
assert(LD->getAddressingMode() == ISD::UNINDEXED &&
"unaligned indexed loads not implemented!");
SDValue Chain = LD->getChain();
SDValue Ptr = LD->getBasePtr();
EVT VT = LD->getValueType(0);
EVT LoadedVT = LD->getMemoryVT();
SDLoc dl(LD);
auto &MF = DAG.getMachineFunction();
if (VT.isFloatingPoint() || VT.isVector()) {
EVT intVT = EVT::getIntegerVT(*DAG.getContext(), LoadedVT.getSizeInBits());
if (isTypeLegal(intVT) && isTypeLegal(LoadedVT)) {
if (!isOperationLegalOrCustom(ISD::LOAD, intVT) &&
LoadedVT.isVector()) {
// Scalarize the load and let the individual components be handled.
return scalarizeVectorLoad(LD, DAG);
}
// Expand to a (misaligned) integer load of the same size,
// then bitconvert to floating point or vector.
SDValue newLoad = DAG.getLoad(intVT, dl, Chain, Ptr,
LD->getMemOperand());
SDValue Result = DAG.getNode(ISD::BITCAST, dl, LoadedVT, newLoad);
if (LoadedVT != VT)
Result = DAG.getNode(VT.isFloatingPoint() ? ISD::FP_EXTEND :
ISD::ANY_EXTEND, dl, VT, Result);
return std::make_pair(Result, newLoad.getValue(1));
}
// Copy the value to a (aligned) stack slot using (unaligned) integer
// loads and stores, then do a (aligned) load from the stack slot.
MVT RegVT = getRegisterType(*DAG.getContext(), intVT);
unsigned LoadedBytes = LoadedVT.getStoreSize();
unsigned RegBytes = RegVT.getSizeInBits() / 8;
unsigned NumRegs = (LoadedBytes + RegBytes - 1) / RegBytes;
// Make sure the stack slot is also aligned for the register type.
SDValue StackBase = DAG.CreateStackTemporary(LoadedVT, RegVT);
auto FrameIndex = cast<FrameIndexSDNode>(StackBase.getNode())->getIndex();
SmallVector<SDValue, 8> Stores;
SDValue StackPtr = StackBase;
unsigned Offset = 0;
EVT PtrVT = Ptr.getValueType();
EVT StackPtrVT = StackPtr.getValueType();
SDValue PtrIncrement = DAG.getConstant(RegBytes, dl, PtrVT);
SDValue StackPtrIncrement = DAG.getConstant(RegBytes, dl, StackPtrVT);
// Do all but one copies using the full register width.
for (unsigned i = 1; i < NumRegs; i++) {
// Load one integer register's worth from the original location.
SDValue Load = DAG.getLoad(
RegVT, dl, Chain, Ptr, LD->getPointerInfo().getWithOffset(Offset),
MinAlign(LD->getAlignment(), Offset), LD->getMemOperand()->getFlags(),
LD->getAAInfo());
// Follow the load with a store to the stack slot. Remember the store.
Stores.push_back(DAG.getStore(
Load.getValue(1), dl, Load, StackPtr,
MachinePointerInfo::getFixedStack(MF, FrameIndex, Offset)));
// Increment the pointers.
Offset += RegBytes;
Ptr = DAG.getObjectPtrOffset(dl, Ptr, PtrIncrement);
StackPtr = DAG.getObjectPtrOffset(dl, StackPtr, StackPtrIncrement);
}
// The last copy may be partial. Do an extending load.
EVT MemVT = EVT::getIntegerVT(*DAG.getContext(),
8 * (LoadedBytes - Offset));
SDValue Load =
DAG.getExtLoad(ISD::EXTLOAD, dl, RegVT, Chain, Ptr,
LD->getPointerInfo().getWithOffset(Offset), MemVT,
MinAlign(LD->getAlignment(), Offset),
LD->getMemOperand()->getFlags(), LD->getAAInfo());
// Follow the load with a store to the stack slot. Remember the store.
// On big-endian machines this requires a truncating store to ensure
// that the bits end up in the right place.
Stores.push_back(DAG.getTruncStore(
Load.getValue(1), dl, Load, StackPtr,
MachinePointerInfo::getFixedStack(MF, FrameIndex, Offset), MemVT));
// The order of the stores doesn't matter - say it with a TokenFactor.
SDValue TF = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Stores);
// Finally, perform the original load only redirected to the stack slot.
Load = DAG.getExtLoad(LD->getExtensionType(), dl, VT, TF, StackBase,
MachinePointerInfo::getFixedStack(MF, FrameIndex, 0),
LoadedVT);
// Callers expect a MERGE_VALUES node.
return std::make_pair(Load, TF);
}
assert(LoadedVT.isInteger() && !LoadedVT.isVector() &&
"Unaligned load of unsupported type.");
// Compute the new VT that is half the size of the old one. This is an
// integer MVT.
unsigned NumBits = LoadedVT.getSizeInBits();
EVT NewLoadedVT;
NewLoadedVT = EVT::getIntegerVT(*DAG.getContext(), NumBits/2);
NumBits >>= 1;
unsigned Alignment = LD->getAlignment();
unsigned IncrementSize = NumBits / 8;
ISD::LoadExtType HiExtType = LD->getExtensionType();
// If the original load is NON_EXTLOAD, the hi part load must be ZEXTLOAD.
if (HiExtType == ISD::NON_EXTLOAD)
HiExtType = ISD::ZEXTLOAD;
// Load the value in two parts
SDValue Lo, Hi;
if (DAG.getDataLayout().isLittleEndian()) {
Lo = DAG.getExtLoad(ISD::ZEXTLOAD, dl, VT, Chain, Ptr, LD->getPointerInfo(),
NewLoadedVT, Alignment, LD->getMemOperand()->getFlags(),
LD->getAAInfo());
Ptr = DAG.getObjectPtrOffset(dl, Ptr, IncrementSize);
Hi = DAG.getExtLoad(HiExtType, dl, VT, Chain, Ptr,
LD->getPointerInfo().getWithOffset(IncrementSize),
NewLoadedVT, MinAlign(Alignment, IncrementSize),
LD->getMemOperand()->getFlags(), LD->getAAInfo());
} else {
Hi = DAG.getExtLoad(HiExtType, dl, VT, Chain, Ptr, LD->getPointerInfo(),
NewLoadedVT, Alignment, LD->getMemOperand()->getFlags(),
LD->getAAInfo());
Ptr = DAG.getObjectPtrOffset(dl, Ptr, IncrementSize);
Lo = DAG.getExtLoad(ISD::ZEXTLOAD, dl, VT, Chain, Ptr,
LD->getPointerInfo().getWithOffset(IncrementSize),
NewLoadedVT, MinAlign(Alignment, IncrementSize),
LD->getMemOperand()->getFlags(), LD->getAAInfo());
}
// aggregate the two parts
SDValue ShiftAmount =
DAG.getConstant(NumBits, dl, getShiftAmountTy(Hi.getValueType(),
DAG.getDataLayout()));
SDValue Result = DAG.getNode(ISD::SHL, dl, VT, Hi, ShiftAmount);
Result = DAG.getNode(ISD::OR, dl, VT, Result, Lo);
SDValue TF = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Lo.getValue(1),
Hi.getValue(1));
return std::make_pair(Result, TF);
}
SDValue TargetLowering::expandUnalignedStore(StoreSDNode *ST,
SelectionDAG &DAG) const {
assert(ST->getAddressingMode() == ISD::UNINDEXED &&
"unaligned indexed stores not implemented!");
SDValue Chain = ST->getChain();
SDValue Ptr = ST->getBasePtr();
SDValue Val = ST->getValue();
EVT VT = Val.getValueType();
int Alignment = ST->getAlignment();
auto &MF = DAG.getMachineFunction();
EVT StoreMemVT = ST->getMemoryVT();
SDLoc dl(ST);
if (StoreMemVT.isFloatingPoint() || StoreMemVT.isVector()) {
EVT intVT = EVT::getIntegerVT(*DAG.getContext(), VT.getSizeInBits());
if (isTypeLegal(intVT)) {
if (!isOperationLegalOrCustom(ISD::STORE, intVT) &&
StoreMemVT.isVector()) {
// Scalarize the store and let the individual components be handled.
SDValue Result = scalarizeVectorStore(ST, DAG);
return Result;
}
// Expand to a bitconvert of the value to the integer type of the
// same size, then a (misaligned) int store.
// FIXME: Does not handle truncating floating point stores!
SDValue Result = DAG.getNode(ISD::BITCAST, dl, intVT, Val);
Result = DAG.getStore(Chain, dl, Result, Ptr, ST->getPointerInfo(),
Alignment, ST->getMemOperand()->getFlags());
return Result;
}
// Do a (aligned) store to a stack slot, then copy from the stack slot
// to the final destination using (unaligned) integer loads and stores.
MVT RegVT = getRegisterType(
*DAG.getContext(),
EVT::getIntegerVT(*DAG.getContext(), StoreMemVT.getSizeInBits()));
EVT PtrVT = Ptr.getValueType();
unsigned StoredBytes = StoreMemVT.getStoreSize();
unsigned RegBytes = RegVT.getSizeInBits() / 8;
unsigned NumRegs = (StoredBytes + RegBytes - 1) / RegBytes;
// Make sure the stack slot is also aligned for the register type.
SDValue StackPtr = DAG.CreateStackTemporary(StoreMemVT, RegVT);
auto FrameIndex = cast<FrameIndexSDNode>(StackPtr.getNode())->getIndex();
// Perform the original store, only redirected to the stack slot.
SDValue Store = DAG.getTruncStore(
Chain, dl, Val, StackPtr,
MachinePointerInfo::getFixedStack(MF, FrameIndex, 0), StoreMemVT);
EVT StackPtrVT = StackPtr.getValueType();
SDValue PtrIncrement = DAG.getConstant(RegBytes, dl, PtrVT);
SDValue StackPtrIncrement = DAG.getConstant(RegBytes, dl, StackPtrVT);
SmallVector<SDValue, 8> Stores;
unsigned Offset = 0;
// Do all but one copies using the full register width.
for (unsigned i = 1; i < NumRegs; i++) {
// Load one integer register's worth from the stack slot.
SDValue Load = DAG.getLoad(
RegVT, dl, Store, StackPtr,
MachinePointerInfo::getFixedStack(MF, FrameIndex, Offset));
// Store it to the final location. Remember the store.
Stores.push_back(DAG.getStore(Load.getValue(1), dl, Load, Ptr,
ST->getPointerInfo().getWithOffset(Offset),
MinAlign(ST->getAlignment(), Offset),
ST->getMemOperand()->getFlags()));
// Increment the pointers.
Offset += RegBytes;
StackPtr = DAG.getObjectPtrOffset(dl, StackPtr, StackPtrIncrement);
Ptr = DAG.getObjectPtrOffset(dl, Ptr, PtrIncrement);
}
// The last store may be partial. Do a truncating store. On big-endian
// machines this requires an extending load from the stack slot to ensure
// that the bits are in the right place.
EVT LoadMemVT =
EVT::getIntegerVT(*DAG.getContext(), 8 * (StoredBytes - Offset));
// Load from the stack slot.
SDValue Load = DAG.getExtLoad(
ISD::EXTLOAD, dl, RegVT, Store, StackPtr,
MachinePointerInfo::getFixedStack(MF, FrameIndex, Offset), LoadMemVT);
Stores.push_back(
DAG.getTruncStore(Load.getValue(1), dl, Load, Ptr,
ST->getPointerInfo().getWithOffset(Offset), LoadMemVT,
MinAlign(ST->getAlignment(), Offset),
ST->getMemOperand()->getFlags(), ST->getAAInfo()));
// The order of the stores doesn't matter - say it with a TokenFactor.
SDValue Result = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Stores);
return Result;
}
assert(StoreMemVT.isInteger() && !StoreMemVT.isVector() &&
"Unaligned store of unknown type.");
// Get the half-size VT
EVT NewStoredVT = StoreMemVT.getHalfSizedIntegerVT(*DAG.getContext());
int NumBits = NewStoredVT.getSizeInBits();
int IncrementSize = NumBits / 8;
// Divide the stored value in two parts.
SDValue ShiftAmount = DAG.getConstant(
NumBits, dl, getShiftAmountTy(Val.getValueType(), DAG.getDataLayout()));
SDValue Lo = Val;
SDValue Hi = DAG.getNode(ISD::SRL, dl, VT, Val, ShiftAmount);
// Store the two parts
SDValue Store1, Store2;
Store1 = DAG.getTruncStore(Chain, dl,
DAG.getDataLayout().isLittleEndian() ? Lo : Hi,
Ptr, ST->getPointerInfo(), NewStoredVT, Alignment,
ST->getMemOperand()->getFlags());
Ptr = DAG.getObjectPtrOffset(dl, Ptr, IncrementSize);
Alignment = MinAlign(Alignment, IncrementSize);
Store2 = DAG.getTruncStore(
Chain, dl, DAG.getDataLayout().isLittleEndian() ? Hi : Lo, Ptr,
ST->getPointerInfo().getWithOffset(IncrementSize), NewStoredVT, Alignment,
ST->getMemOperand()->getFlags(), ST->getAAInfo());
SDValue Result =
DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Store1, Store2);
return Result;
}
SDValue
TargetLowering::IncrementMemoryAddress(SDValue Addr, SDValue Mask,
const SDLoc &DL, EVT DataVT,
SelectionDAG &DAG,
bool IsCompressedMemory) const {
SDValue Increment;
EVT AddrVT = Addr.getValueType();
EVT MaskVT = Mask.getValueType();
assert(DataVT.getVectorNumElements() == MaskVT.getVectorNumElements() &&
"Incompatible types of Data and Mask");
if (IsCompressedMemory) {
if (DataVT.isScalableVector())
report_fatal_error(
"Cannot currently handle compressed memory with scalable vectors");
// Incrementing the pointer according to number of '1's in the mask.
EVT MaskIntVT = EVT::getIntegerVT(*DAG.getContext(), MaskVT.getSizeInBits());
SDValue MaskInIntReg = DAG.getBitcast(MaskIntVT, Mask);
if (MaskIntVT.getSizeInBits() < 32) {
MaskInIntReg = DAG.getNode(ISD::ZERO_EXTEND, DL, MVT::i32, MaskInIntReg);
MaskIntVT = MVT::i32;
}
// Count '1's with POPCNT.
Increment = DAG.getNode(ISD::CTPOP, DL, MaskIntVT, MaskInIntReg);
Increment = DAG.getZExtOrTrunc(Increment, DL, AddrVT);
// Scale is an element size in bytes.
SDValue Scale = DAG.getConstant(DataVT.getScalarSizeInBits() / 8, DL,
AddrVT);
Increment = DAG.getNode(ISD::MUL, DL, AddrVT, Increment, Scale);
} else if (DataVT.isScalableVector()) {
Increment = DAG.getVScale(DL, AddrVT,
APInt(AddrVT.getSizeInBits().getFixedSize(),
DataVT.getStoreSize().getKnownMinSize()));
} else
Increment = DAG.getConstant(DataVT.getStoreSize(), DL, AddrVT);
return DAG.getNode(ISD::ADD, DL, AddrVT, Addr, Increment);
}
static SDValue clampDynamicVectorIndex(SelectionDAG &DAG,
SDValue Idx,
EVT VecVT,
const SDLoc &dl) {
if (isa<ConstantSDNode>(Idx))
return Idx;
EVT IdxVT = Idx.getValueType();
unsigned NElts = VecVT.getVectorNumElements();
if (isPowerOf2_32(NElts)) {
APInt Imm = APInt::getLowBitsSet(IdxVT.getSizeInBits(),
Log2_32(NElts));
return DAG.getNode(ISD::AND, dl, IdxVT, Idx,
DAG.getConstant(Imm, dl, IdxVT));
}
return DAG.getNode(ISD::UMIN, dl, IdxVT, Idx,
DAG.getConstant(NElts - 1, dl, IdxVT));
}
SDValue TargetLowering::getVectorElementPointer(SelectionDAG &DAG,
SDValue VecPtr, EVT VecVT,
SDValue Index) const {
SDLoc dl(Index);
// Make sure the index type is big enough to compute in.
Index = DAG.getZExtOrTrunc(Index, dl, VecPtr.getValueType());
EVT EltVT = VecVT.getVectorElementType();
// Calculate the element offset and add it to the pointer.
unsigned EltSize = EltVT.getSizeInBits() / 8; // FIXME: should be ABI size.
assert(EltSize * 8 == EltVT.getSizeInBits() &&
"Converting bits to bytes lost precision");
Index = clampDynamicVectorIndex(DAG, Index, VecVT, dl);
EVT IdxVT = Index.getValueType();
Index = DAG.getNode(ISD::MUL, dl, IdxVT, Index,
DAG.getConstant(EltSize, dl, IdxVT));
return DAG.getMemBasePlusOffset(VecPtr, Index, dl);
}
//===----------------------------------------------------------------------===//
// Implementation of Emulated TLS Model
//===----------------------------------------------------------------------===//
SDValue TargetLowering::LowerToTLSEmulatedModel(const GlobalAddressSDNode *GA,
SelectionDAG &DAG) const {
// Access to address of TLS varialbe xyz is lowered to a function call:
// __emutls_get_address( address of global variable named "__emutls_v.xyz" )
EVT PtrVT = getPointerTy(DAG.getDataLayout());
PointerType *VoidPtrType = Type::getInt8PtrTy(*DAG.getContext());
SDLoc dl(GA);
ArgListTy Args;
ArgListEntry Entry;
std::string NameString = ("__emutls_v." + GA->getGlobal()->getName()).str();
Module *VariableModule = const_cast<Module*>(GA->getGlobal()->getParent());
StringRef EmuTlsVarName(NameString);
GlobalVariable *EmuTlsVar = VariableModule->getNamedGlobal(EmuTlsVarName);
assert(EmuTlsVar && "Cannot find EmuTlsVar ");
Entry.Node = DAG.getGlobalAddress(EmuTlsVar, dl, PtrVT);
Entry.Ty = VoidPtrType;
Args.push_back(Entry);
SDValue EmuTlsGetAddr = DAG.getExternalSymbol("__emutls_get_address", PtrVT);
TargetLowering::CallLoweringInfo CLI(DAG);
CLI.setDebugLoc(dl).setChain(DAG.getEntryNode());
CLI.setLibCallee(CallingConv::C, VoidPtrType, EmuTlsGetAddr, std::move(Args));
std::pair<SDValue, SDValue> CallResult = LowerCallTo(CLI);
// TLSADDR will be codegen'ed as call. Inform MFI that function has calls.
// At last for X86 targets, maybe good for other targets too?
MachineFrameInfo &MFI = DAG.getMachineFunction().getFrameInfo();
MFI.setAdjustsStack(true); // Is this only for X86 target?
MFI.setHasCalls(true);
assert((GA->getOffset() == 0) &&
"Emulated TLS must have zero offset in GlobalAddressSDNode");
return CallResult.first;
}
SDValue TargetLowering::lowerCmpEqZeroToCtlzSrl(SDValue Op,
SelectionDAG &DAG) const {
assert((Op->getOpcode() == ISD::SETCC) && "Input has to be a SETCC node.");
if (!isCtlzFast())
return SDValue();
ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(2))->get();
SDLoc dl(Op);
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
if (C->isNullValue() && CC == ISD::SETEQ) {
EVT VT = Op.getOperand(0).getValueType();
SDValue Zext = Op.getOperand(0);
if (VT.bitsLT(MVT::i32)) {
VT = MVT::i32;
Zext = DAG.getNode(ISD::ZERO_EXTEND, dl, VT, Op.getOperand(0));
}
unsigned Log2b = Log2_32(VT.getSizeInBits());
SDValue Clz = DAG.getNode(ISD::CTLZ, dl, VT, Zext);
SDValue Scc = DAG.getNode(ISD::SRL, dl, VT, Clz,
DAG.getConstant(Log2b, dl, MVT::i32));
return DAG.getNode(ISD::TRUNCATE, dl, MVT::i32, Scc);
}
}
return SDValue();
}
SDValue TargetLowering::expandAddSubSat(SDNode *Node, SelectionDAG &DAG) const {
unsigned Opcode = Node->getOpcode();
SDValue LHS = Node->getOperand(0);
SDValue RHS = Node->getOperand(1);
EVT VT = LHS.getValueType();
SDLoc dl(Node);
assert(VT == RHS.getValueType() && "Expected operands to be the same type");
assert(VT.isInteger() && "Expected operands to be integers");
// usub.sat(a, b) -> umax(a, b) - b
if (Opcode == ISD::USUBSAT && isOperationLegalOrCustom(ISD::UMAX, VT)) {
SDValue Max = DAG.getNode(ISD::UMAX, dl, VT, LHS, RHS);
return DAG.getNode(ISD::SUB, dl, VT, Max, RHS);
}
if (Opcode == ISD::UADDSAT && isOperationLegalOrCustom(ISD::UMIN, VT)) {
SDValue InvRHS = DAG.getNOT(dl, RHS, VT);
SDValue Min = DAG.getNode(ISD::UMIN, dl, VT, LHS, InvRHS);
return DAG.getNode(ISD::ADD, dl, VT, Min, RHS);
}
unsigned OverflowOp;
switch (Opcode) {
case ISD::SADDSAT:
OverflowOp = ISD::SADDO;
break;
case ISD::UADDSAT:
OverflowOp = ISD::UADDO;
break;
case ISD::SSUBSAT:
OverflowOp = ISD::SSUBO;
break;
case ISD::USUBSAT:
OverflowOp = ISD::USUBO;
break;
default:
llvm_unreachable("Expected method to receive signed or unsigned saturation "
"addition or subtraction node.");
}
// FIXME: Should really try to split the vector in case it's legal on a
// subvector.
if (VT.isVector() && !isOperationLegalOrCustom(ISD::VSELECT, VT))
return DAG.UnrollVectorOp(Node);
unsigned BitWidth = LHS.getScalarValueSizeInBits();
EVT BoolVT = getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(), VT);
SDValue Result = DAG.getNode(OverflowOp, dl, DAG.getVTList(VT, BoolVT),
LHS, RHS);
SDValue SumDiff = Result.getValue(0);
SDValue Overflow = Result.getValue(1);
SDValue Zero = DAG.getConstant(0, dl, VT);
SDValue AllOnes = DAG.getAllOnesConstant(dl, VT);
if (Opcode == ISD::UADDSAT) {
if (getBooleanContents(VT) == ZeroOrNegativeOneBooleanContent) {
// (LHS + RHS) | OverflowMask
SDValue OverflowMask = DAG.getSExtOrTrunc(Overflow, dl, VT);
return DAG.getNode(ISD::OR, dl, VT, SumDiff, OverflowMask);
}
// Overflow ? 0xffff.... : (LHS + RHS)
return DAG.getSelect(dl, VT, Overflow, AllOnes, SumDiff);
} else if (Opcode == ISD::USUBSAT) {
if (getBooleanContents(VT) == ZeroOrNegativeOneBooleanContent) {
// (LHS - RHS) & ~OverflowMask
SDValue OverflowMask = DAG.getSExtOrTrunc(Overflow, dl, VT);
SDValue Not = DAG.getNOT(dl, OverflowMask, VT);
return DAG.getNode(ISD::AND, dl, VT, SumDiff, Not);
}
// Overflow ? 0 : (LHS - RHS)
return DAG.getSelect(dl, VT, Overflow, Zero, SumDiff);
} else {
// SatMax -> Overflow && SumDiff < 0
// SatMin -> Overflow && SumDiff >= 0
APInt MinVal = APInt::getSignedMinValue(BitWidth);
APInt MaxVal = APInt::getSignedMaxValue(BitWidth);
SDValue SatMin = DAG.getConstant(MinVal, dl, VT);
SDValue SatMax = DAG.getConstant(MaxVal, dl, VT);
SDValue SumNeg = DAG.getSetCC(dl, BoolVT, SumDiff, Zero, ISD::SETLT);
Result = DAG.getSelect(dl, VT, SumNeg, SatMax, SatMin);
return DAG.getSelect(dl, VT, Overflow, Result, SumDiff);
}
}
SDValue
TargetLowering::expandFixedPointMul(SDNode *Node, SelectionDAG &DAG) const {
assert((Node->getOpcode() == ISD::SMULFIX ||
Node->getOpcode() == ISD::UMULFIX ||
Node->getOpcode() == ISD::SMULFIXSAT ||
Node->getOpcode() == ISD::UMULFIXSAT) &&
"Expected a fixed point multiplication opcode");
SDLoc dl(Node);
SDValue LHS = Node->getOperand(0);
SDValue RHS = Node->getOperand(1);
EVT VT = LHS.getValueType();
unsigned Scale = Node->getConstantOperandVal(2);
bool Saturating = (Node->getOpcode() == ISD::SMULFIXSAT ||
Node->getOpcode() == ISD::UMULFIXSAT);
bool Signed = (Node->getOpcode() == ISD::SMULFIX ||
Node->getOpcode() == ISD::SMULFIXSAT);
EVT BoolVT = getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(), VT);
unsigned VTSize = VT.getScalarSizeInBits();
if (!Scale) {
// [us]mul.fix(a, b, 0) -> mul(a, b)
if (!Saturating) {
if (isOperationLegalOrCustom(ISD::MUL, VT))
return DAG.getNode(ISD::MUL, dl, VT, LHS, RHS);
} else if (Signed && isOperationLegalOrCustom(ISD::SMULO, VT)) {
SDValue Result =
DAG.getNode(ISD::SMULO, dl, DAG.getVTList(VT, BoolVT), LHS, RHS);
SDValue Product = Result.getValue(0);
SDValue Overflow = Result.getValue(1);
SDValue Zero = DAG.getConstant(0, dl, VT);
APInt MinVal = APInt::getSignedMinValue(VTSize);
APInt MaxVal = APInt::getSignedMaxValue(VTSize);
SDValue SatMin = DAG.getConstant(MinVal, dl, VT);
SDValue SatMax = DAG.getConstant(MaxVal, dl, VT);
SDValue ProdNeg = DAG.getSetCC(dl, BoolVT, Product, Zero, ISD::SETLT);
Result = DAG.getSelect(dl, VT, ProdNeg, SatMax, SatMin);
return DAG.getSelect(dl, VT, Overflow, Result, Product);
} else if (!Signed && isOperationLegalOrCustom(ISD::UMULO, VT)) {
SDValue Result =
DAG.getNode(ISD::UMULO, dl, DAG.getVTList(VT, BoolVT), LHS, RHS);
SDValue Product = Result.getValue(0);
SDValue Overflow = Result.getValue(1);
APInt MaxVal = APInt::getMaxValue(VTSize);
SDValue SatMax = DAG.getConstant(MaxVal, dl, VT);
return DAG.getSelect(dl, VT, Overflow, SatMax, Product);
}
}
assert(((Signed && Scale < VTSize) || (!Signed && Scale <= VTSize)) &&
"Expected scale to be less than the number of bits if signed or at "
"most the number of bits if unsigned.");
assert(LHS.getValueType() == RHS.getValueType() &&
"Expected both operands to be the same type");
// Get the upper and lower bits of the result.
SDValue Lo, Hi;
unsigned LoHiOp = Signed ? ISD::SMUL_LOHI : ISD::UMUL_LOHI;
unsigned HiOp = Signed ? ISD::MULHS : ISD::MULHU;
if (isOperationLegalOrCustom(LoHiOp, VT)) {
SDValue Result = DAG.getNode(LoHiOp, dl, DAG.getVTList(VT, VT), LHS, RHS);
Lo = Result.getValue(0);
Hi = Result.getValue(1);
} else if (isOperationLegalOrCustom(HiOp, VT)) {
Lo = DAG.getNode(ISD::MUL, dl, VT, LHS, RHS);
Hi = DAG.getNode(HiOp, dl, VT, LHS, RHS);
} else if (VT.isVector()) {
return SDValue();
} else {
report_fatal_error("Unable to expand fixed point multiplication.");
}
if (Scale == VTSize)
// Result is just the top half since we'd be shifting by the width of the
// operand. Overflow impossible so this works for both UMULFIX and
// UMULFIXSAT.
return Hi;
// The result will need to be shifted right by the scale since both operands
// are scaled. The result is given to us in 2 halves, so we only want part of
// both in the result.
EVT ShiftTy = getShiftAmountTy(VT, DAG.getDataLayout());
SDValue Result = DAG.getNode(ISD::FSHR, dl, VT, Hi, Lo,
DAG.getConstant(Scale, dl, ShiftTy));
if (!Saturating)
return Result;
if (!Signed) {
// Unsigned overflow happened if the upper (VTSize - Scale) bits (of the
// widened multiplication) aren't all zeroes.
// Saturate to max if ((Hi >> Scale) != 0),
// which is the same as if (Hi > ((1 << Scale) - 1))
APInt MaxVal = APInt::getMaxValue(VTSize);
SDValue LowMask = DAG.getConstant(APInt::getLowBitsSet(VTSize, Scale),
dl, VT);
Result = DAG.getSelectCC(dl, Hi, LowMask,
DAG.getConstant(MaxVal, dl, VT), Result,
ISD::SETUGT);
return Result;
}
// Signed overflow happened if the upper (VTSize - Scale + 1) bits (of the
// widened multiplication) aren't all ones or all zeroes.
SDValue SatMin = DAG.getConstant(APInt::getSignedMinValue(VTSize), dl, VT);
SDValue SatMax = DAG.getConstant(APInt::getSignedMaxValue(VTSize), dl, VT);
if (Scale == 0) {
SDValue Sign = DAG.getNode(ISD::SRA, dl, VT, Lo,
DAG.getConstant(VTSize - 1, dl, ShiftTy));
SDValue Overflow = DAG.getSetCC(dl, BoolVT, Hi, Sign, ISD::SETNE);
// Saturated to SatMin if wide product is negative, and SatMax if wide
// product is positive ...
SDValue Zero = DAG.getConstant(0, dl, VT);
SDValue ResultIfOverflow = DAG.getSelectCC(dl, Hi, Zero, SatMin, SatMax,
ISD::SETLT);
// ... but only if we overflowed.
return DAG.getSelect(dl, VT, Overflow, ResultIfOverflow, Result);
}
// We handled Scale==0 above so all the bits to examine is in Hi.
// Saturate to max if ((Hi >> (Scale - 1)) > 0),
// which is the same as if (Hi > (1 << (Scale - 1)) - 1)
SDValue LowMask = DAG.getConstant(APInt::getLowBitsSet(VTSize, Scale - 1),
dl, VT);
Result = DAG.getSelectCC(dl, Hi, LowMask, SatMax, Result, ISD::SETGT);
// Saturate to min if (Hi >> (Scale - 1)) < -1),
// which is the same as if (HI < (-1 << (Scale - 1))
SDValue HighMask =
DAG.getConstant(APInt::getHighBitsSet(VTSize, VTSize - Scale + 1),
dl, VT);
Result = DAG.getSelectCC(dl, Hi, HighMask, SatMin, Result, ISD::SETLT);
return Result;
}
SDValue
TargetLowering::expandFixedPointDiv(unsigned Opcode, const SDLoc &dl,
SDValue LHS, SDValue RHS,
unsigned Scale, SelectionDAG &DAG) const {
assert((Opcode == ISD::SDIVFIX || Opcode == ISD::SDIVFIXSAT ||
Opcode == ISD::UDIVFIX || Opcode == ISD::UDIVFIXSAT) &&
"Expected a fixed point division opcode");
EVT VT = LHS.getValueType();
bool Signed = Opcode == ISD::SDIVFIX || Opcode == ISD::SDIVFIXSAT;
bool Saturating = Opcode == ISD::SDIVFIXSAT || Opcode == ISD::UDIVFIXSAT;
EVT BoolVT = getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(), VT);
// If there is enough room in the type to upscale the LHS or downscale the
// RHS before the division, we can perform it in this type without having to
// resize. For signed operations, the LHS headroom is the number of
// redundant sign bits, and for unsigned ones it is the number of zeroes.
// The headroom for the RHS is the number of trailing zeroes.
unsigned LHSLead = Signed ? DAG.ComputeNumSignBits(LHS) - 1
: DAG.computeKnownBits(LHS).countMinLeadingZeros();
unsigned RHSTrail = DAG.computeKnownBits(RHS).countMinTrailingZeros();
// For signed saturating operations, we need to be able to detect true integer
// division overflow; that is, when you have MIN / -EPS. However, this
// is undefined behavior and if we emit divisions that could take such
// values it may cause undesired behavior (arithmetic exceptions on x86, for
// example).
// Avoid this by requiring an extra bit so that we never get this case.
// FIXME: This is a bit unfortunate as it means that for an 8-bit 7-scale
// signed saturating division, we need to emit a whopping 32-bit division.
if (LHSLead + RHSTrail < Scale + (unsigned)(Saturating && Signed))
return SDValue();
unsigned LHSShift = std::min(LHSLead, Scale);
unsigned RHSShift = Scale - LHSShift;
// At this point, we know that if we shift the LHS up by LHSShift and the
// RHS down by RHSShift, we can emit a regular division with a final scaling
// factor of Scale.
EVT ShiftTy = getShiftAmountTy(VT, DAG.getDataLayout());
if (LHSShift)
LHS = DAG.getNode(ISD::SHL, dl, VT, LHS,
DAG.getConstant(LHSShift, dl, ShiftTy));
if (RHSShift)
RHS = DAG.getNode(Signed ? ISD::SRA : ISD::SRL, dl, VT, RHS,
DAG.getConstant(RHSShift, dl, ShiftTy));
SDValue Quot;
if (Signed) {
// For signed operations, if the resulting quotient is negative and the
// remainder is nonzero, subtract 1 from the quotient to round towards
// negative infinity.
SDValue Rem;
// FIXME: Ideally we would always produce an SDIVREM here, but if the
// type isn't legal, SDIVREM cannot be expanded. There is no reason why
// we couldn't just form a libcall, but the type legalizer doesn't do it.
if (isTypeLegal(VT) &&
isOperationLegalOrCustom(ISD::SDIVREM, VT)) {
Quot = DAG.getNode(ISD::SDIVREM, dl,
DAG.getVTList(VT, VT),
LHS, RHS);
Rem = Quot.getValue(1);
Quot = Quot.getValue(0);
} else {
Quot = DAG.getNode(ISD::SDIV, dl, VT,
LHS, RHS);
Rem = DAG.getNode(ISD::SREM, dl, VT,
LHS, RHS);
}
SDValue Zero = DAG.getConstant(0, dl, VT);
SDValue RemNonZero = DAG.getSetCC(dl, BoolVT, Rem, Zero, ISD::SETNE);
SDValue LHSNeg = DAG.getSetCC(dl, BoolVT, LHS, Zero, ISD::SETLT);
SDValue RHSNeg = DAG.getSetCC(dl, BoolVT, RHS, Zero, ISD::SETLT);
SDValue QuotNeg = DAG.getNode(ISD::XOR, dl, BoolVT, LHSNeg, RHSNeg);
SDValue Sub1 = DAG.getNode(ISD::SUB, dl, VT, Quot,
DAG.getConstant(1, dl, VT));
Quot = DAG.getSelect(dl, VT,
DAG.getNode(ISD::AND, dl, BoolVT, RemNonZero, QuotNeg),
Sub1, Quot);
} else
Quot = DAG.getNode(ISD::UDIV, dl, VT,
LHS, RHS);
return Quot;
}
void TargetLowering::expandUADDSUBO(
SDNode *Node, SDValue &Result, SDValue &Overflow, SelectionDAG &DAG) const {
SDLoc dl(Node);
SDValue LHS = Node->getOperand(0);
SDValue RHS = Node->getOperand(1);
bool IsAdd = Node->getOpcode() == ISD::UADDO;
// If ADD/SUBCARRY is legal, use that instead.
unsigned OpcCarry = IsAdd ? ISD::ADDCARRY : ISD::SUBCARRY;
if (isOperationLegalOrCustom(OpcCarry, Node->getValueType(0))) {
SDValue CarryIn = DAG.getConstant(0, dl, Node->getValueType(1));
SDValue NodeCarry = DAG.getNode(OpcCarry, dl, Node->getVTList(),
{ LHS, RHS, CarryIn });
Result = SDValue(NodeCarry.getNode(), 0);
Overflow = SDValue(NodeCarry.getNode(), 1);
return;
}
Result = DAG.getNode(IsAdd ? ISD::ADD : ISD::SUB, dl,
LHS.getValueType(), LHS, RHS);
EVT ResultType = Node->getValueType(1);
EVT SetCCType = getSetCCResultType(
DAG.getDataLayout(), *DAG.getContext(), Node->getValueType(0));
ISD::CondCode CC = IsAdd ? ISD::SETULT : ISD::SETUGT;
SDValue SetCC = DAG.getSetCC(dl, SetCCType, Result, LHS, CC);
Overflow = DAG.getBoolExtOrTrunc(SetCC, dl, ResultType, ResultType);
}
void TargetLowering::expandSADDSUBO(
SDNode *Node, SDValue &Result, SDValue &Overflow, SelectionDAG &DAG) const {
SDLoc dl(Node);
SDValue LHS = Node->getOperand(0);
SDValue RHS = Node->getOperand(1);
bool IsAdd = Node->getOpcode() == ISD::SADDO;
Result = DAG.getNode(IsAdd ? ISD::ADD : ISD::SUB, dl,
LHS.getValueType(), LHS, RHS);
EVT ResultType = Node->getValueType(1);
EVT OType = getSetCCResultType(
DAG.getDataLayout(), *DAG.getContext(), Node->getValueType(0));
// If SADDSAT/SSUBSAT is legal, compare results to detect overflow.
unsigned OpcSat = IsAdd ? ISD::SADDSAT : ISD::SSUBSAT;
if (isOperationLegalOrCustom(OpcSat, LHS.getValueType())) {
SDValue Sat = DAG.getNode(OpcSat, dl, LHS.getValueType(), LHS, RHS);
SDValue SetCC = DAG.getSetCC(dl, OType, Result, Sat, ISD::SETNE);
Overflow = DAG.getBoolExtOrTrunc(SetCC, dl, ResultType, ResultType);
return;
}
SDValue Zero = DAG.getConstant(0, dl, LHS.getValueType());
// For an addition, the result should be less than one of the operands (LHS)
// if and only if the other operand (RHS) is negative, otherwise there will
// be overflow.
// For a subtraction, the result should be less than one of the operands
// (LHS) if and only if the other operand (RHS) is (non-zero) positive,
// otherwise there will be overflow.
SDValue ResultLowerThanLHS = DAG.getSetCC(dl, OType, Result, LHS, ISD::SETLT);
SDValue ConditionRHS =
DAG.getSetCC(dl, OType, RHS, Zero, IsAdd ? ISD::SETLT : ISD::SETGT);
Overflow = DAG.getBoolExtOrTrunc(
DAG.getNode(ISD::XOR, dl, OType, ConditionRHS, ResultLowerThanLHS), dl,
ResultType, ResultType);
}
bool TargetLowering::expandMULO(SDNode *Node, SDValue &Result,
SDValue &Overflow, SelectionDAG &DAG) const {
SDLoc dl(Node);
EVT VT = Node->getValueType(0);
EVT SetCCVT = getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(), VT);
SDValue LHS = Node->getOperand(0);
SDValue RHS = Node->getOperand(1);
bool isSigned = Node->getOpcode() == ISD::SMULO;
// For power-of-two multiplications we can use a simpler shift expansion.
if (ConstantSDNode *RHSC = isConstOrConstSplat(RHS)) {
const APInt &C = RHSC->getAPIntValue();
// mulo(X, 1 << S) -> { X << S, (X << S) >> S != X }
if (C.isPowerOf2()) {
// smulo(x, signed_min) is same as umulo(x, signed_min).
bool UseArithShift = isSigned && !C.isMinSignedValue();
EVT ShiftAmtTy = getShiftAmountTy(VT, DAG.getDataLayout());
SDValue ShiftAmt = DAG.getConstant(C.logBase2(), dl, ShiftAmtTy);
Result = DAG.getNode(ISD::SHL, dl, VT, LHS, ShiftAmt);
Overflow = DAG.getSetCC(dl, SetCCVT,
DAG.getNode(UseArithShift ? ISD::SRA : ISD::SRL,
dl, VT, Result, ShiftAmt),
LHS, ISD::SETNE);
return true;
}
}
EVT WideVT = EVT::getIntegerVT(*DAG.getContext(), VT.getScalarSizeInBits() * 2);
if (VT.isVector())
WideVT = EVT::getVectorVT(*DAG.getContext(), WideVT,
VT.getVectorNumElements());
SDValue BottomHalf;
SDValue TopHalf;
static const unsigned Ops[2][3] =
{ { ISD::MULHU, ISD::UMUL_LOHI, ISD::ZERO_EXTEND },
{ ISD::MULHS, ISD::SMUL_LOHI, ISD::SIGN_EXTEND }};
if (isOperationLegalOrCustom(Ops[isSigned][0], VT)) {
BottomHalf = DAG.getNode(ISD::MUL, dl, VT, LHS, RHS);
TopHalf = DAG.getNode(Ops[isSigned][0], dl, VT, LHS, RHS);
} else if (isOperationLegalOrCustom(Ops[isSigned][1], VT)) {
BottomHalf = DAG.getNode(Ops[isSigned][1], dl, DAG.getVTList(VT, VT), LHS,
RHS);
TopHalf = BottomHalf.getValue(1);
} else if (isTypeLegal(WideVT)) {
LHS = DAG.getNode(Ops[isSigned][2], dl, WideVT, LHS);
RHS = DAG.getNode(Ops[isSigned][2], dl, WideVT, RHS);
SDValue Mul = DAG.getNode(ISD::MUL, dl, WideVT, LHS, RHS);
BottomHalf = DAG.getNode(ISD::TRUNCATE, dl, VT, Mul);
SDValue ShiftAmt = DAG.getConstant(VT.getScalarSizeInBits(), dl,
getShiftAmountTy(WideVT, DAG.getDataLayout()));
TopHalf = DAG.getNode(ISD::TRUNCATE, dl, VT,
DAG.getNode(ISD::SRL, dl, WideVT, Mul, ShiftAmt));
} else {
if (VT.isVector())
return false;
// We can fall back to a libcall with an illegal type for the MUL if we
// have a libcall big enough.
// Also, we can fall back to a division in some cases, but that's a big
// performance hit in the general case.
RTLIB::Libcall LC = RTLIB::UNKNOWN_LIBCALL;
if (WideVT == MVT::i16)
LC = RTLIB::MUL_I16;
else if (WideVT == MVT::i32)
LC = RTLIB::MUL_I32;
else if (WideVT == MVT::i64)
LC = RTLIB::MUL_I64;
else if (WideVT == MVT::i128)
LC = RTLIB::MUL_I128;
assert(LC != RTLIB::UNKNOWN_LIBCALL && "Cannot expand this operation!");
SDValue HiLHS;
SDValue HiRHS;
if (isSigned) {
// The high part is obtained by SRA'ing all but one of the bits of low
// part.
unsigned LoSize = VT.getSizeInBits();
HiLHS =
DAG.getNode(ISD::SRA, dl, VT, LHS,
DAG.getConstant(LoSize - 1, dl,
getPointerTy(DAG.getDataLayout())));
HiRHS =
DAG.getNode(ISD::SRA, dl, VT, RHS,
DAG.getConstant(LoSize - 1, dl,
getPointerTy(DAG.getDataLayout())));
} else {
HiLHS = DAG.getConstant(0, dl, VT);
HiRHS = DAG.getConstant(0, dl, VT);
}
// Here we're passing the 2 arguments explicitly as 4 arguments that are
// pre-lowered to the correct types. This all depends upon WideVT not
// being a legal type for the architecture and thus has to be split to
// two arguments.
SDValue Ret;
TargetLowering::MakeLibCallOptions CallOptions;
CallOptions.setSExt(isSigned);
CallOptions.setIsPostTypeLegalization(true);
if (shouldSplitFunctionArgumentsAsLittleEndian(DAG.getDataLayout())) {
// Halves of WideVT are packed into registers in different order
// depending on platform endianness. This is usually handled by
// the C calling convention, but we can't defer to it in
// the legalizer.
SDValue Args[] = { LHS, HiLHS, RHS, HiRHS };
Ret = makeLibCall(DAG, LC, WideVT, Args, CallOptions, dl).first;
} else {
SDValue Args[] = { HiLHS, LHS, HiRHS, RHS };
Ret = makeLibCall(DAG, LC, WideVT, Args, CallOptions, dl).first;
}
assert(Ret.getOpcode() == ISD::MERGE_VALUES &&
"Ret value is a collection of constituent nodes holding result.");
if (DAG.getDataLayout().isLittleEndian()) {
// Same as above.
BottomHalf = Ret.getOperand(0);
TopHalf = Ret.getOperand(1);
} else {
BottomHalf = Ret.getOperand(1);
TopHalf = Ret.getOperand(0);
}
}
Result = BottomHalf;
if (isSigned) {
SDValue ShiftAmt = DAG.getConstant(
VT.getScalarSizeInBits() - 1, dl,
getShiftAmountTy(BottomHalf.getValueType(), DAG.getDataLayout()));
SDValue Sign = DAG.getNode(ISD::SRA, dl, VT, BottomHalf, ShiftAmt);
Overflow = DAG.getSetCC(dl, SetCCVT, TopHalf, Sign, ISD::SETNE);
} else {
Overflow = DAG.getSetCC(dl, SetCCVT, TopHalf,
DAG.getConstant(0, dl, VT), ISD::SETNE);
}
// Truncate the result if SetCC returns a larger type than needed.
EVT RType = Node->getValueType(1);
if (RType.getSizeInBits() < Overflow.getValueSizeInBits())
Overflow = DAG.getNode(ISD::TRUNCATE, dl, RType, Overflow);
assert(RType.getSizeInBits() == Overflow.getValueSizeInBits() &&
"Unexpected result type for S/UMULO legalization");
return true;
}
SDValue TargetLowering::expandVecReduce(SDNode *Node, SelectionDAG &DAG) const {
SDLoc dl(Node);
bool NoNaN = Node->getFlags().hasNoNaNs();
unsigned BaseOpcode = 0;
switch (Node->getOpcode()) {
default: llvm_unreachable("Expected VECREDUCE opcode");
case ISD::VECREDUCE_FADD: BaseOpcode = ISD::FADD; break;
case ISD::VECREDUCE_FMUL: BaseOpcode = ISD::FMUL; break;
case ISD::VECREDUCE_ADD: BaseOpcode = ISD::ADD; break;
case ISD::VECREDUCE_MUL: BaseOpcode = ISD::MUL; break;
case ISD::VECREDUCE_AND: BaseOpcode = ISD::AND; break;
case ISD::VECREDUCE_OR: BaseOpcode = ISD::OR; break;
case ISD::VECREDUCE_XOR: BaseOpcode = ISD::XOR; break;
case ISD::VECREDUCE_SMAX: BaseOpcode = ISD::SMAX; break;
case ISD::VECREDUCE_SMIN: BaseOpcode = ISD::SMIN; break;
case ISD::VECREDUCE_UMAX: BaseOpcode = ISD::UMAX; break;
case ISD::VECREDUCE_UMIN: BaseOpcode = ISD::UMIN; break;
case ISD::VECREDUCE_FMAX:
BaseOpcode = NoNaN ? ISD::FMAXNUM : ISD::FMAXIMUM;
break;
case ISD::VECREDUCE_FMIN:
BaseOpcode = NoNaN ? ISD::FMINNUM : ISD::FMINIMUM;
break;
}
SDValue Op = Node->getOperand(0);
EVT VT = Op.getValueType();
// Try to use a shuffle reduction for power of two vectors.
if (VT.isPow2VectorType()) {
while (VT.getVectorNumElements() > 1) {
EVT HalfVT = VT.getHalfNumVectorElementsVT(*DAG.getContext());
if (!isOperationLegalOrCustom(BaseOpcode, HalfVT))
break;
SDValue Lo, Hi;
std::tie(Lo, Hi) = DAG.SplitVector(Op, dl);
Op = DAG.getNode(BaseOpcode, dl, HalfVT, Lo, Hi);
VT = HalfVT;
}
}
EVT EltVT = VT.getVectorElementType();
unsigned NumElts = VT.getVectorNumElements();
SmallVector<SDValue, 8> Ops;
DAG.ExtractVectorElements(Op, Ops, 0, NumElts);
SDValue Res = Ops[0];
for (unsigned i = 1; i < NumElts; i++)
Res = DAG.getNode(BaseOpcode, dl, EltVT, Res, Ops[i], Node->getFlags());
// Result type may be wider than element type.
if (EltVT != Node->getValueType(0))
Res = DAG.getNode(ISD::ANY_EXTEND, dl, Node->getValueType(0), Res);
return Res;
}
bool TargetLowering::expandREM(SDNode *Node, SDValue &Result,
SelectionDAG &DAG) const {
EVT VT = Node->getValueType(0);
SDLoc dl(Node);
bool isSigned = Node->getOpcode() == ISD::SREM;
unsigned DivOpc = isSigned ? ISD::SDIV : ISD::UDIV;
unsigned DivRemOpc = isSigned ? ISD::SDIVREM : ISD::UDIVREM;
SDValue Dividend = Node->getOperand(0);
SDValue Divisor = Node->getOperand(1);
if (isOperationLegalOrCustom(DivRemOpc, VT)) {
SDVTList VTs = DAG.getVTList(VT, VT);
Result = DAG.getNode(DivRemOpc, dl, VTs, Dividend, Divisor).getValue(1);
return true;
} else if (isOperationLegalOrCustom(DivOpc, VT)) {
// X % Y -> X-X/Y*Y
SDValue Divide = DAG.getNode(DivOpc, dl, VT, Dividend, Divisor);
SDValue Mul = DAG.getNode(ISD::MUL, dl, VT, Divide, Divisor);
Result = DAG.getNode(ISD::SUB, dl, VT, Dividend, Mul);
return true;
}
return false;
}
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