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llvm-mirror/lib/Target/X86/X86ISelDAGToDAG.cpp
Sanjay Patel f84fc5ad12 [x86] try harder to form LEA from ADD to avoid flag conflicts (PR40483) 
LEA doesn't affect flags, so use it more liberally to replace an ADD when
we know that the ADD operands affect flags.

In the motivating example from PR40483:
https://bugs.llvm.org/show_bug.cgi?id=40483
...this lets us avoid duplicating a math op just to avoid flag conflict.

As mentioned in the TODO comments, this heuristic can be extended to
fire more often if that leads to more improvements.

Differential Revision: https://reviews.llvm.org/D64707

llvm-svn: 366431
2019-07-18 12:48:01 +00:00

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//===- X86ISelDAGToDAG.cpp - A DAG pattern matching inst selector for X86 -===//
//
// 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 file defines a DAG pattern matching instruction selector for X86,
// converting from a legalized dag to a X86 dag.
//
//===----------------------------------------------------------------------===//
#include "X86.h"
#include "X86MachineFunctionInfo.h"
#include "X86RegisterInfo.h"
#include "X86Subtarget.h"
#include "X86TargetMachine.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/SelectionDAGISel.h"
#include "llvm/Config/llvm-config.h"
#include "llvm/IR/ConstantRange.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/Type.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/KnownBits.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include <stdint.h>
using namespace llvm;
#define DEBUG_TYPE "x86-isel"
STATISTIC(NumLoadMoved, "Number of loads moved below TokenFactor");
static cl::opt<bool> AndImmShrink("x86-and-imm-shrink", cl::init(true),
cl::desc("Enable setting constant bits to reduce size of mask immediates"),
cl::Hidden);
//===----------------------------------------------------------------------===//
// Pattern Matcher Implementation
//===----------------------------------------------------------------------===//
namespace {
/// This corresponds to X86AddressMode, but uses SDValue's instead of register
/// numbers for the leaves of the matched tree.
struct X86ISelAddressMode {
enum {
RegBase,
FrameIndexBase
} BaseType;
// This is really a union, discriminated by BaseType!
SDValue Base_Reg;
int Base_FrameIndex;
unsigned Scale;
SDValue IndexReg;
int32_t Disp;
SDValue Segment;
const GlobalValue *GV;
const Constant *CP;
const BlockAddress *BlockAddr;
const char *ES;
MCSymbol *MCSym;
int JT;
unsigned Align; // CP alignment.
unsigned char SymbolFlags; // X86II::MO_*
bool NegateIndex = false;
X86ISelAddressMode()
: BaseType(RegBase), Base_FrameIndex(0), Scale(1), IndexReg(), Disp(0),
Segment(), GV(nullptr), CP(nullptr), BlockAddr(nullptr), ES(nullptr),
MCSym(nullptr), JT(-1), Align(0), SymbolFlags(X86II::MO_NO_FLAG) {}
bool hasSymbolicDisplacement() const {
return GV != nullptr || CP != nullptr || ES != nullptr ||
MCSym != nullptr || JT != -1 || BlockAddr != nullptr;
}
bool hasBaseOrIndexReg() const {
return BaseType == FrameIndexBase ||
IndexReg.getNode() != nullptr || Base_Reg.getNode() != nullptr;
}
/// Return true if this addressing mode is already RIP-relative.
bool isRIPRelative() const {
if (BaseType != RegBase) return false;
if (RegisterSDNode *RegNode =
dyn_cast_or_null<RegisterSDNode>(Base_Reg.getNode()))
return RegNode->getReg() == X86::RIP;
return false;
}
void setBaseReg(SDValue Reg) {
BaseType = RegBase;
Base_Reg = Reg;
}
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void dump(SelectionDAG *DAG = nullptr) {
dbgs() << "X86ISelAddressMode " << this << '\n';
dbgs() << "Base_Reg ";
if (Base_Reg.getNode())
Base_Reg.getNode()->dump(DAG);
else
dbgs() << "nul\n";
if (BaseType == FrameIndexBase)
dbgs() << " Base.FrameIndex " << Base_FrameIndex << '\n';
dbgs() << " Scale " << Scale << '\n'
<< "IndexReg ";
if (NegateIndex)
dbgs() << "negate ";
if (IndexReg.getNode())
IndexReg.getNode()->dump(DAG);
else
dbgs() << "nul\n";
dbgs() << " Disp " << Disp << '\n'
<< "GV ";
if (GV)
GV->dump();
else
dbgs() << "nul";
dbgs() << " CP ";
if (CP)
CP->dump();
else
dbgs() << "nul";
dbgs() << '\n'
<< "ES ";
if (ES)
dbgs() << ES;
else
dbgs() << "nul";
dbgs() << " MCSym ";
if (MCSym)
dbgs() << MCSym;
else
dbgs() << "nul";
dbgs() << " JT" << JT << " Align" << Align << '\n';
}
#endif
};
}
namespace {
//===--------------------------------------------------------------------===//
/// ISel - X86-specific code to select X86 machine instructions for
/// SelectionDAG operations.
///
class X86DAGToDAGISel final : public SelectionDAGISel {
/// Keep a pointer to the X86Subtarget around so that we can
/// make the right decision when generating code for different targets.
const X86Subtarget *Subtarget;
/// If true, selector should try to optimize for code size instead of
/// performance.
bool OptForSize;
/// If true, selector should try to optimize for minimum code size.
bool OptForMinSize;
/// Disable direct TLS access through segment registers.
bool IndirectTlsSegRefs;
public:
explicit X86DAGToDAGISel(X86TargetMachine &tm, CodeGenOpt::Level OptLevel)
: SelectionDAGISel(tm, OptLevel), Subtarget(nullptr), OptForSize(false),
OptForMinSize(false), IndirectTlsSegRefs(false) {}
StringRef getPassName() const override {
return "X86 DAG->DAG Instruction Selection";
}
bool runOnMachineFunction(MachineFunction &MF) override {
// Reset the subtarget each time through.
Subtarget = &MF.getSubtarget<X86Subtarget>();
IndirectTlsSegRefs = MF.getFunction().hasFnAttribute(
"indirect-tls-seg-refs");
// OptFor[Min]Size are used in pattern predicates that isel is matching.
OptForSize = MF.getFunction().hasOptSize();
OptForMinSize = MF.getFunction().hasMinSize();
assert((!OptForMinSize || OptForSize) &&
"OptForMinSize implies OptForSize");
SelectionDAGISel::runOnMachineFunction(MF);
return true;
}
void EmitFunctionEntryCode() override;
bool IsProfitableToFold(SDValue N, SDNode *U, SDNode *Root) const override;
void PreprocessISelDAG() override;
void PostprocessISelDAG() override;
// Include the pieces autogenerated from the target description.
#include "X86GenDAGISel.inc"
private:
void Select(SDNode *N) override;
bool foldOffsetIntoAddress(uint64_t Offset, X86ISelAddressMode &AM);
bool matchLoadInAddress(LoadSDNode *N, X86ISelAddressMode &AM);
bool matchWrapper(SDValue N, X86ISelAddressMode &AM);
bool matchAddress(SDValue N, X86ISelAddressMode &AM);
bool matchVectorAddress(SDValue N, X86ISelAddressMode &AM);
bool matchAdd(SDValue &N, X86ISelAddressMode &AM, unsigned Depth);
bool matchAddressRecursively(SDValue N, X86ISelAddressMode &AM,
unsigned Depth);
bool matchAddressBase(SDValue N, X86ISelAddressMode &AM);
bool selectAddr(SDNode *Parent, SDValue N, SDValue &Base,
SDValue &Scale, SDValue &Index, SDValue &Disp,
SDValue &Segment);
bool selectVectorAddr(SDNode *Parent, SDValue N, SDValue &Base,
SDValue &Scale, SDValue &Index, SDValue &Disp,
SDValue &Segment);
bool selectMOV64Imm32(SDValue N, SDValue &Imm);
bool selectLEAAddr(SDValue N, SDValue &Base,
SDValue &Scale, SDValue &Index, SDValue &Disp,
SDValue &Segment);
bool selectLEA64_32Addr(SDValue N, SDValue &Base,
SDValue &Scale, SDValue &Index, SDValue &Disp,
SDValue &Segment);
bool selectTLSADDRAddr(SDValue N, SDValue &Base,
SDValue &Scale, SDValue &Index, SDValue &Disp,
SDValue &Segment);
bool selectScalarSSELoad(SDNode *Root, SDNode *Parent, SDValue N,
SDValue &Base, SDValue &Scale,
SDValue &Index, SDValue &Disp,
SDValue &Segment,
SDValue &NodeWithChain);
bool selectRelocImm(SDValue N, SDValue &Op);
bool tryFoldLoad(SDNode *Root, SDNode *P, SDValue N,
SDValue &Base, SDValue &Scale,
SDValue &Index, SDValue &Disp,
SDValue &Segment);
// Convenience method where P is also root.
bool tryFoldLoad(SDNode *P, SDValue N,
SDValue &Base, SDValue &Scale,
SDValue &Index, SDValue &Disp,
SDValue &Segment) {
return tryFoldLoad(P, P, N, Base, Scale, Index, Disp, Segment);
}
/// Implement addressing mode selection for inline asm expressions.
bool SelectInlineAsmMemoryOperand(const SDValue &Op,
unsigned ConstraintID,
std::vector<SDValue> &OutOps) override;
void emitSpecialCodeForMain();
inline void getAddressOperands(X86ISelAddressMode &AM, const SDLoc &DL,
MVT VT, SDValue &Base, SDValue &Scale,
SDValue &Index, SDValue &Disp,
SDValue &Segment) {
if (AM.BaseType == X86ISelAddressMode::FrameIndexBase)
Base = CurDAG->getTargetFrameIndex(
AM.Base_FrameIndex, TLI->getPointerTy(CurDAG->getDataLayout()));
else if (AM.Base_Reg.getNode())
Base = AM.Base_Reg;
else
Base = CurDAG->getRegister(0, VT);
Scale = getI8Imm(AM.Scale, DL);
// Negate the index if needed.
if (AM.NegateIndex) {
unsigned NegOpc = VT == MVT::i64 ? X86::NEG64r : X86::NEG32r;
SDValue Neg = SDValue(CurDAG->getMachineNode(NegOpc, DL, VT, MVT::i32,
AM.IndexReg), 0);
AM.IndexReg = Neg;
}
if (AM.IndexReg.getNode())
Index = AM.IndexReg;
else
Index = CurDAG->getRegister(0, VT);
// These are 32-bit even in 64-bit mode since RIP-relative offset
// is 32-bit.
if (AM.GV)
Disp = CurDAG->getTargetGlobalAddress(AM.GV, SDLoc(),
MVT::i32, AM.Disp,
AM.SymbolFlags);
else if (AM.CP)
Disp = CurDAG->getTargetConstantPool(AM.CP, MVT::i32,
AM.Align, AM.Disp, AM.SymbolFlags);
else if (AM.ES) {
assert(!AM.Disp && "Non-zero displacement is ignored with ES.");
Disp = CurDAG->getTargetExternalSymbol(AM.ES, MVT::i32, AM.SymbolFlags);
} else if (AM.MCSym) {
assert(!AM.Disp && "Non-zero displacement is ignored with MCSym.");
assert(AM.SymbolFlags == 0 && "oo");
Disp = CurDAG->getMCSymbol(AM.MCSym, MVT::i32);
} else if (AM.JT != -1) {
assert(!AM.Disp && "Non-zero displacement is ignored with JT.");
Disp = CurDAG->getTargetJumpTable(AM.JT, MVT::i32, AM.SymbolFlags);
} else if (AM.BlockAddr)
Disp = CurDAG->getTargetBlockAddress(AM.BlockAddr, MVT::i32, AM.Disp,
AM.SymbolFlags);
else
Disp = CurDAG->getTargetConstant(AM.Disp, DL, MVT::i32);
if (AM.Segment.getNode())
Segment = AM.Segment;
else
Segment = CurDAG->getRegister(0, MVT::i16);
}
// Utility function to determine whether we should avoid selecting
// immediate forms of instructions for better code size or not.
// At a high level, we'd like to avoid such instructions when
// we have similar constants used within the same basic block
// that can be kept in a register.
//
bool shouldAvoidImmediateInstFormsForSize(SDNode *N) const {
uint32_t UseCount = 0;
// Do not want to hoist if we're not optimizing for size.
// TODO: We'd like to remove this restriction.
// See the comment in X86InstrInfo.td for more info.
if (!OptForSize)
return false;
// Walk all the users of the immediate.
for (SDNode::use_iterator UI = N->use_begin(),
UE = N->use_end(); (UI != UE) && (UseCount < 2); ++UI) {
SDNode *User = *UI;
// This user is already selected. Count it as a legitimate use and
// move on.
if (User->isMachineOpcode()) {
UseCount++;
continue;
}
// We want to count stores of immediates as real uses.
if (User->getOpcode() == ISD::STORE &&
User->getOperand(1).getNode() == N) {
UseCount++;
continue;
}
// We don't currently match users that have > 2 operands (except
// for stores, which are handled above)
// Those instruction won't match in ISEL, for now, and would
// be counted incorrectly.
// This may change in the future as we add additional instruction
// types.
if (User->getNumOperands() != 2)
continue;
// Immediates that are used for offsets as part of stack
// manipulation should be left alone. These are typically
// used to indicate SP offsets for argument passing and
// will get pulled into stores/pushes (implicitly).
if (User->getOpcode() == X86ISD::ADD ||
User->getOpcode() == ISD::ADD ||
User->getOpcode() == X86ISD::SUB ||
User->getOpcode() == ISD::SUB) {
// Find the other operand of the add/sub.
SDValue OtherOp = User->getOperand(0);
if (OtherOp.getNode() == N)
OtherOp = User->getOperand(1);
// Don't count if the other operand is SP.
RegisterSDNode *RegNode;
if (OtherOp->getOpcode() == ISD::CopyFromReg &&
(RegNode = dyn_cast_or_null<RegisterSDNode>(
OtherOp->getOperand(1).getNode())))
if ((RegNode->getReg() == X86::ESP) ||
(RegNode->getReg() == X86::RSP))
continue;
}
// ... otherwise, count this and move on.
UseCount++;
}
// If we have more than 1 use, then recommend for hoisting.
return (UseCount > 1);
}
/// Return a target constant with the specified value of type i8.
inline SDValue getI8Imm(unsigned Imm, const SDLoc &DL) {
return CurDAG->getTargetConstant(Imm, DL, MVT::i8);
}
/// Return a target constant with the specified value, of type i32.
inline SDValue getI32Imm(unsigned Imm, const SDLoc &DL) {
return CurDAG->getTargetConstant(Imm, DL, MVT::i32);
}
/// Return a target constant with the specified value, of type i64.
inline SDValue getI64Imm(uint64_t Imm, const SDLoc &DL) {
return CurDAG->getTargetConstant(Imm, DL, MVT::i64);
}
SDValue getExtractVEXTRACTImmediate(SDNode *N, unsigned VecWidth,
const SDLoc &DL) {
assert((VecWidth == 128 || VecWidth == 256) && "Unexpected vector width");
uint64_t Index = N->getConstantOperandVal(1);
MVT VecVT = N->getOperand(0).getSimpleValueType();
return getI8Imm((Index * VecVT.getScalarSizeInBits()) / VecWidth, DL);
}
SDValue getInsertVINSERTImmediate(SDNode *N, unsigned VecWidth,
const SDLoc &DL) {
assert((VecWidth == 128 || VecWidth == 256) && "Unexpected vector width");
uint64_t Index = N->getConstantOperandVal(2);
MVT VecVT = N->getSimpleValueType(0);
return getI8Imm((Index * VecVT.getScalarSizeInBits()) / VecWidth, DL);
}
// Helper to detect unneeded and instructions on shift amounts. Called
// from PatFrags in tablegen.
bool isUnneededShiftMask(SDNode *N, unsigned Width) const {
assert(N->getOpcode() == ISD::AND && "Unexpected opcode");
const APInt &Val = cast<ConstantSDNode>(N->getOperand(1))->getAPIntValue();
if (Val.countTrailingOnes() >= Width)
return true;
APInt Mask = Val | CurDAG->computeKnownBits(N->getOperand(0)).Zero;
return Mask.countTrailingOnes() >= Width;
}
/// Return an SDNode that returns the value of the global base register.
/// Output instructions required to initialize the global base register,
/// if necessary.
SDNode *getGlobalBaseReg();
/// Return a reference to the TargetMachine, casted to the target-specific
/// type.
const X86TargetMachine &getTargetMachine() const {
return static_cast<const X86TargetMachine &>(TM);
}
/// Return a reference to the TargetInstrInfo, casted to the target-specific
/// type.
const X86InstrInfo *getInstrInfo() const {
return Subtarget->getInstrInfo();
}
/// Address-mode matching performs shift-of-and to and-of-shift
/// reassociation in order to expose more scaled addressing
/// opportunities.
bool ComplexPatternFuncMutatesDAG() const override {
return true;
}
bool isSExtAbsoluteSymbolRef(unsigned Width, SDNode *N) const;
/// Returns whether this is a relocatable immediate in the range
/// [-2^Width .. 2^Width-1].
template <unsigned Width> bool isSExtRelocImm(SDNode *N) const {
if (auto *CN = dyn_cast<ConstantSDNode>(N))
return isInt<Width>(CN->getSExtValue());
return isSExtAbsoluteSymbolRef(Width, N);
}
// Indicates we should prefer to use a non-temporal load for this load.
bool useNonTemporalLoad(LoadSDNode *N) const {
if (!N->isNonTemporal())
return false;
unsigned StoreSize = N->getMemoryVT().getStoreSize();
if (N->getAlignment() < StoreSize)
return false;
switch (StoreSize) {
default: llvm_unreachable("Unsupported store size");
case 4:
case 8:
return false;
case 16:
return Subtarget->hasSSE41();
case 32:
return Subtarget->hasAVX2();
case 64:
return Subtarget->hasAVX512();
}
}
bool foldLoadStoreIntoMemOperand(SDNode *Node);
MachineSDNode *matchBEXTRFromAndImm(SDNode *Node);
bool matchBitExtract(SDNode *Node);
bool shrinkAndImmediate(SDNode *N);
bool isMaskZeroExtended(SDNode *N) const;
bool tryShiftAmountMod(SDNode *N);
bool tryShrinkShlLogicImm(SDNode *N);
bool tryVPTESTM(SDNode *Root, SDValue Setcc, SDValue Mask);
MachineSDNode *emitPCMPISTR(unsigned ROpc, unsigned MOpc, bool MayFoldLoad,
const SDLoc &dl, MVT VT, SDNode *Node);
MachineSDNode *emitPCMPESTR(unsigned ROpc, unsigned MOpc, bool MayFoldLoad,
const SDLoc &dl, MVT VT, SDNode *Node,
SDValue &InFlag);
bool tryOptimizeRem8Extend(SDNode *N);
bool onlyUsesZeroFlag(SDValue Flags) const;
bool hasNoSignFlagUses(SDValue Flags) const;
bool hasNoCarryFlagUses(SDValue Flags) const;
};
}
// Returns true if this masked compare can be implemented legally with this
// type.
static bool isLegalMaskCompare(SDNode *N, const X86Subtarget *Subtarget) {
unsigned Opcode = N->getOpcode();
if (Opcode == X86ISD::CMPM || Opcode == ISD::SETCC ||
Opcode == X86ISD::CMPM_SAE || Opcode == X86ISD::VFPCLASS) {
// We can get 256-bit 8 element types here without VLX being enabled. When
// this happens we will use 512-bit operations and the mask will not be
// zero extended.
EVT OpVT = N->getOperand(0).getValueType();
if (OpVT.is256BitVector() || OpVT.is128BitVector())
return Subtarget->hasVLX();
return true;
}
// Scalar opcodes use 128 bit registers, but aren't subject to the VLX check.
if (Opcode == X86ISD::VFPCLASSS || Opcode == X86ISD::FSETCCM ||
Opcode == X86ISD::FSETCCM_SAE)
return true;
return false;
}
// Returns true if we can assume the writer of the mask has zero extended it
// for us.
bool X86DAGToDAGISel::isMaskZeroExtended(SDNode *N) const {
// If this is an AND, check if we have a compare on either side. As long as
// one side guarantees the mask is zero extended, the AND will preserve those
// zeros.
if (N->getOpcode() == ISD::AND)
return isLegalMaskCompare(N->getOperand(0).getNode(), Subtarget) ||
isLegalMaskCompare(N->getOperand(1).getNode(), Subtarget);
return isLegalMaskCompare(N, Subtarget);
}
bool
X86DAGToDAGISel::IsProfitableToFold(SDValue N, SDNode *U, SDNode *Root) const {
if (OptLevel == CodeGenOpt::None) return false;
if (!N.hasOneUse())
return false;
if (N.getOpcode() != ISD::LOAD)
return true;
// Don't fold non-temporal loads if we have an instruction for them.
if (useNonTemporalLoad(cast<LoadSDNode>(N)))
return false;
// If N is a load, do additional profitability checks.
if (U == Root) {
switch (U->getOpcode()) {
default: break;
case X86ISD::ADD:
case X86ISD::ADC:
case X86ISD::SUB:
case X86ISD::SBB:
case X86ISD::AND:
case X86ISD::XOR:
case X86ISD::OR:
case ISD::ADD:
case ISD::ADDCARRY:
case ISD::AND:
case ISD::OR:
case ISD::XOR: {
SDValue Op1 = U->getOperand(1);
// If the other operand is a 8-bit immediate we should fold the immediate
// instead. This reduces code size.
// e.g.
// movl 4(%esp), %eax
// addl $4, %eax
// vs.
// movl $4, %eax
// addl 4(%esp), %eax
// The former is 2 bytes shorter. In case where the increment is 1, then
// the saving can be 4 bytes (by using incl %eax).
if (ConstantSDNode *Imm = dyn_cast<ConstantSDNode>(Op1)) {
if (Imm->getAPIntValue().isSignedIntN(8))
return false;
// If this is a 64-bit AND with an immediate that fits in 32-bits,
// prefer using the smaller and over folding the load. This is needed to
// make sure immediates created by shrinkAndImmediate are always folded.
// Ideally we would narrow the load during DAG combine and get the
// best of both worlds.
if (U->getOpcode() == ISD::AND &&
Imm->getAPIntValue().getBitWidth() == 64 &&
Imm->getAPIntValue().isIntN(32))
return false;
// If this really a zext_inreg that can be represented with a movzx
// instruction, prefer that.
// TODO: We could shrink the load and fold if it is non-volatile.
if (U->getOpcode() == ISD::AND &&
(Imm->getAPIntValue() == UINT8_MAX ||
Imm->getAPIntValue() == UINT16_MAX ||
Imm->getAPIntValue() == UINT32_MAX))
return false;
// ADD/SUB with can negate the immediate and use the opposite operation
// to fit 128 into a sign extended 8 bit immediate.
if ((U->getOpcode() == ISD::ADD || U->getOpcode() == ISD::SUB) &&
(-Imm->getAPIntValue()).isSignedIntN(8))
return false;
}
// If the other operand is a TLS address, we should fold it instead.
// This produces
// movl %gs:0, %eax
// leal i@NTPOFF(%eax), %eax
// instead of
// movl $i@NTPOFF, %eax
// addl %gs:0, %eax
// if the block also has an access to a second TLS address this will save
// a load.
// FIXME: This is probably also true for non-TLS addresses.
if (Op1.getOpcode() == X86ISD::Wrapper) {
SDValue Val = Op1.getOperand(0);
if (Val.getOpcode() == ISD::TargetGlobalTLSAddress)
return false;
}
// Don't fold load if this matches the BTS/BTR/BTC patterns.
// BTS: (or X, (shl 1, n))
// BTR: (and X, (rotl -2, n))
// BTC: (xor X, (shl 1, n))
if (U->getOpcode() == ISD::OR || U->getOpcode() == ISD::XOR) {
if (U->getOperand(0).getOpcode() == ISD::SHL &&
isOneConstant(U->getOperand(0).getOperand(0)))
return false;
if (U->getOperand(1).getOpcode() == ISD::SHL &&
isOneConstant(U->getOperand(1).getOperand(0)))
return false;
}
if (U->getOpcode() == ISD::AND) {
SDValue U0 = U->getOperand(0);
SDValue U1 = U->getOperand(1);
if (U0.getOpcode() == ISD::ROTL) {
auto *C = dyn_cast<ConstantSDNode>(U0.getOperand(0));
if (C && C->getSExtValue() == -2)
return false;
}
if (U1.getOpcode() == ISD::ROTL) {
auto *C = dyn_cast<ConstantSDNode>(U1.getOperand(0));
if (C && C->getSExtValue() == -2)
return false;
}
}
break;
}
case ISD::SHL:
case ISD::SRA:
case ISD::SRL:
// Don't fold a load into a shift by immediate. The BMI2 instructions
// support folding a load, but not an immediate. The legacy instructions
// support folding an immediate, but can't fold a load. Folding an
// immediate is preferable to folding a load.
if (isa<ConstantSDNode>(U->getOperand(1)))
return false;
break;
}
}
// Prevent folding a load if this can implemented with an insert_subreg or
// a move that implicitly zeroes.
if (Root->getOpcode() == ISD::INSERT_SUBVECTOR &&
isNullConstant(Root->getOperand(2)) &&
(Root->getOperand(0).isUndef() ||
ISD::isBuildVectorAllZeros(Root->getOperand(0).getNode())))
return false;
return true;
}
/// Replace the original chain operand of the call with
/// load's chain operand and move load below the call's chain operand.
static void moveBelowOrigChain(SelectionDAG *CurDAG, SDValue Load,
SDValue Call, SDValue OrigChain) {
SmallVector<SDValue, 8> Ops;
SDValue Chain = OrigChain.getOperand(0);
if (Chain.getNode() == Load.getNode())
Ops.push_back(Load.getOperand(0));
else {
assert(Chain.getOpcode() == ISD::TokenFactor &&
"Unexpected chain operand");
for (unsigned i = 0, e = Chain.getNumOperands(); i != e; ++i)
if (Chain.getOperand(i).getNode() == Load.getNode())
Ops.push_back(Load.getOperand(0));
else
Ops.push_back(Chain.getOperand(i));
SDValue NewChain =
CurDAG->getNode(ISD::TokenFactor, SDLoc(Load), MVT::Other, Ops);
Ops.clear();
Ops.push_back(NewChain);
}
Ops.append(OrigChain->op_begin() + 1, OrigChain->op_end());
CurDAG->UpdateNodeOperands(OrigChain.getNode(), Ops);
CurDAG->UpdateNodeOperands(Load.getNode(), Call.getOperand(0),
Load.getOperand(1), Load.getOperand(2));
Ops.clear();
Ops.push_back(SDValue(Load.getNode(), 1));
Ops.append(Call->op_begin() + 1, Call->op_end());
CurDAG->UpdateNodeOperands(Call.getNode(), Ops);
}
/// Return true if call address is a load and it can be
/// moved below CALLSEQ_START and the chains leading up to the call.
/// Return the CALLSEQ_START by reference as a second output.
/// In the case of a tail call, there isn't a callseq node between the call
/// chain and the load.
static bool isCalleeLoad(SDValue Callee, SDValue &Chain, bool HasCallSeq) {
// The transformation is somewhat dangerous if the call's chain was glued to
// the call. After MoveBelowOrigChain the load is moved between the call and
// the chain, this can create a cycle if the load is not folded. So it is
// *really* important that we are sure the load will be folded.
if (Callee.getNode() == Chain.getNode() || !Callee.hasOneUse())
return false;
LoadSDNode *LD = dyn_cast<LoadSDNode>(Callee.getNode());
if (!LD ||
LD->isVolatile() ||
LD->getAddressingMode() != ISD::UNINDEXED ||
LD->getExtensionType() != ISD::NON_EXTLOAD)
return false;
// Now let's find the callseq_start.
while (HasCallSeq && Chain.getOpcode() != ISD::CALLSEQ_START) {
if (!Chain.hasOneUse())
return false;
Chain = Chain.getOperand(0);
}
if (!Chain.getNumOperands())
return false;
// Since we are not checking for AA here, conservatively abort if the chain
// writes to memory. It's not safe to move the callee (a load) across a store.
if (isa<MemSDNode>(Chain.getNode()) &&
cast<MemSDNode>(Chain.getNode())->writeMem())
return false;
if (Chain.getOperand(0).getNode() == Callee.getNode())
return true;
if (Chain.getOperand(0).getOpcode() == ISD::TokenFactor &&
Callee.getValue(1).isOperandOf(Chain.getOperand(0).getNode()) &&
Callee.getValue(1).hasOneUse())
return true;
return false;
}
void X86DAGToDAGISel::PreprocessISelDAG() {
for (SelectionDAG::allnodes_iterator I = CurDAG->allnodes_begin(),
E = CurDAG->allnodes_end(); I != E; ) {
SDNode *N = &*I++; // Preincrement iterator to avoid invalidation issues.
// If this is a target specific AND node with no flag usages, turn it back
// into ISD::AND to enable test instruction matching.
if (N->getOpcode() == X86ISD::AND && !N->hasAnyUseOfValue(1)) {
SDValue Res = CurDAG->getNode(ISD::AND, SDLoc(N), N->getValueType(0),
N->getOperand(0), N->getOperand(1));
--I;
CurDAG->ReplaceAllUsesOfValueWith(SDValue(N, 0), Res);
++I;
CurDAG->DeleteNode(N);
continue;
}
switch (N->getOpcode()) {
case ISD::FP_TO_SINT:
case ISD::FP_TO_UINT: {
// Replace vector fp_to_s/uint with their X86 specific equivalent so we
// don't need 2 sets of patterns.
if (!N->getSimpleValueType(0).isVector())
break;
unsigned NewOpc;
switch (N->getOpcode()) {
default: llvm_unreachable("Unexpected opcode!");
case ISD::FP_TO_SINT: NewOpc = X86ISD::CVTTP2SI; break;
case ISD::FP_TO_UINT: NewOpc = X86ISD::CVTTP2UI; break;
}
SDValue Res = CurDAG->getNode(NewOpc, SDLoc(N), N->getValueType(0),
N->getOperand(0));
--I;
CurDAG->ReplaceAllUsesOfValueWith(SDValue(N, 0), Res);
++I;
CurDAG->DeleteNode(N);
continue;
}
case ISD::SHL:
case ISD::SRA:
case ISD::SRL: {
// Replace vector shifts with their X86 specific equivalent so we don't
// need 2 sets of patterns.
if (!N->getValueType(0).isVector())
break;
unsigned NewOpc;
switch (N->getOpcode()) {
default: llvm_unreachable("Unexpected opcode!");
case ISD::SHL: NewOpc = X86ISD::VSHLV; break;
case ISD::SRA: NewOpc = X86ISD::VSRAV; break;
case ISD::SRL: NewOpc = X86ISD::VSRLV; break;
}
SDValue Res = CurDAG->getNode(NewOpc, SDLoc(N), N->getValueType(0),
N->getOperand(0), N->getOperand(1));
--I;
CurDAG->ReplaceAllUsesOfValueWith(SDValue(N, 0), Res);
++I;
CurDAG->DeleteNode(N);
continue;
}
case ISD::ANY_EXTEND:
case ISD::ANY_EXTEND_VECTOR_INREG: {
// Replace vector any extend with the zero extend equivalents so we don't
// need 2 sets of patterns. Ignore vXi1 extensions.
if (!N->getValueType(0).isVector() ||
N->getOperand(0).getScalarValueSizeInBits() == 1)
break;
unsigned NewOpc = N->getOpcode() == ISD::ANY_EXTEND
? ISD::ZERO_EXTEND
: ISD::ZERO_EXTEND_VECTOR_INREG;
SDValue Res = CurDAG->getNode(NewOpc, SDLoc(N), N->getValueType(0),
N->getOperand(0));
--I;
CurDAG->ReplaceAllUsesOfValueWith(SDValue(N, 0), Res);
++I;
CurDAG->DeleteNode(N);
continue;
}
case ISD::FCEIL:
case ISD::FFLOOR:
case ISD::FTRUNC:
case ISD::FNEARBYINT:
case ISD::FRINT: {
// Replace fp rounding with their X86 specific equivalent so we don't
// need 2 sets of patterns.
unsigned Imm;
switch (N->getOpcode()) {
default: llvm_unreachable("Unexpected opcode!");
case ISD::FCEIL: Imm = 0xA; break;
case ISD::FFLOOR: Imm = 0x9; break;
case ISD::FTRUNC: Imm = 0xB; break;
case ISD::FNEARBYINT: Imm = 0xC; break;
case ISD::FRINT: Imm = 0x4; break;
}
SDLoc dl(N);
SDValue Res = CurDAG->getNode(X86ISD::VRNDSCALE, dl,
N->getValueType(0),
N->getOperand(0),
CurDAG->getConstant(Imm, dl, MVT::i8));
--I;
CurDAG->ReplaceAllUsesOfValueWith(SDValue(N, 0), Res);
++I;
CurDAG->DeleteNode(N);
continue;
}
case X86ISD::FANDN:
case X86ISD::FAND:
case X86ISD::FOR:
case X86ISD::FXOR: {
// Widen scalar fp logic ops to vector to reduce isel patterns.
// FIXME: Can we do this during lowering/combine.
MVT VT = N->getSimpleValueType(0);
if (VT.isVector() || VT == MVT::f128)
break;
MVT VecVT = VT == MVT::f64 ? MVT::v2f64 : MVT::v4f32;
SDLoc dl(N);
SDValue Op0 = CurDAG->getNode(ISD::SCALAR_TO_VECTOR, dl, VecVT,
N->getOperand(0));
SDValue Op1 = CurDAG->getNode(ISD::SCALAR_TO_VECTOR, dl, VecVT,
N->getOperand(1));
SDValue Res;
if (Subtarget->hasSSE2()) {
EVT IntVT = EVT(VecVT).changeVectorElementTypeToInteger();
Op0 = CurDAG->getNode(ISD::BITCAST, dl, IntVT, Op0);
Op1 = CurDAG->getNode(ISD::BITCAST, dl, IntVT, Op1);
unsigned Opc;
switch (N->getOpcode()) {
default: llvm_unreachable("Unexpected opcode!");
case X86ISD::FANDN: Opc = X86ISD::ANDNP; break;
case X86ISD::FAND: Opc = ISD::AND; break;
case X86ISD::FOR: Opc = ISD::OR; break;
case X86ISD::FXOR: Opc = ISD::XOR; break;
}
Res = CurDAG->getNode(Opc, dl, IntVT, Op0, Op1);
Res = CurDAG->getNode(ISD::BITCAST, dl, VecVT, Res);
} else {
Res = CurDAG->getNode(N->getOpcode(), dl, VecVT, Op0, Op1);
}
Res = CurDAG->getNode(ISD::EXTRACT_VECTOR_ELT, dl, VT, Res,
CurDAG->getIntPtrConstant(0, dl));
--I;
CurDAG->ReplaceAllUsesOfValueWith(SDValue(N, 0), Res);
++I;
CurDAG->DeleteNode(N);
continue;
}
}
if (OptLevel != CodeGenOpt::None &&
// Only do this when the target can fold the load into the call or
// jmp.
!Subtarget->useRetpolineIndirectCalls() &&
((N->getOpcode() == X86ISD::CALL && !Subtarget->slowTwoMemOps()) ||
(N->getOpcode() == X86ISD::TC_RETURN &&
(Subtarget->is64Bit() ||
!getTargetMachine().isPositionIndependent())))) {
/// Also try moving call address load from outside callseq_start to just
/// before the call to allow it to be folded.
///
/// [Load chain]
/// ^
/// |
/// [Load]
/// ^ ^
/// | |
/// / \--
/// / |
///[CALLSEQ_START] |
/// ^ |
/// | |
/// [LOAD/C2Reg] |
/// | |
/// \ /
/// \ /
/// [CALL]
bool HasCallSeq = N->getOpcode() == X86ISD::CALL;
SDValue Chain = N->getOperand(0);
SDValue Load = N->getOperand(1);
if (!isCalleeLoad(Load, Chain, HasCallSeq))
continue;
moveBelowOrigChain(CurDAG, Load, SDValue(N, 0), Chain);
++NumLoadMoved;
continue;
}
// Lower fpround and fpextend nodes that target the FP stack to be store and
// load to the stack. This is a gross hack. We would like to simply mark
// these as being illegal, but when we do that, legalize produces these when
// it expands calls, then expands these in the same legalize pass. We would
// like dag combine to be able to hack on these between the call expansion
// and the node legalization. As such this pass basically does "really
// late" legalization of these inline with the X86 isel pass.
// FIXME: This should only happen when not compiled with -O0.
switch (N->getOpcode()) {
default: continue;
case ISD::FP_ROUND:
case ISD::FP_EXTEND:
{
MVT SrcVT = N->getOperand(0).getSimpleValueType();
MVT DstVT = N->getSimpleValueType(0);
// If any of the sources are vectors, no fp stack involved.
if (SrcVT.isVector() || DstVT.isVector())
continue;
// If the source and destination are SSE registers, then this is a legal
// conversion that should not be lowered.
const X86TargetLowering *X86Lowering =
static_cast<const X86TargetLowering *>(TLI);
bool SrcIsSSE = X86Lowering->isScalarFPTypeInSSEReg(SrcVT);
bool DstIsSSE = X86Lowering->isScalarFPTypeInSSEReg(DstVT);
if (SrcIsSSE && DstIsSSE)
continue;
if (!SrcIsSSE && !DstIsSSE) {
// If this is an FPStack extension, it is a noop.
if (N->getOpcode() == ISD::FP_EXTEND)
continue;
// If this is a value-preserving FPStack truncation, it is a noop.
if (N->getConstantOperandVal(1))
continue;
}
// Here we could have an FP stack truncation or an FPStack <-> SSE convert.
// FPStack has extload and truncstore. SSE can fold direct loads into other
// operations. Based on this, decide what we want to do.
MVT MemVT;
if (N->getOpcode() == ISD::FP_ROUND)
MemVT = DstVT; // FP_ROUND must use DstVT, we can't do a 'trunc load'.
else
MemVT = SrcIsSSE ? SrcVT : DstVT;
SDValue MemTmp = CurDAG->CreateStackTemporary(MemVT);
SDLoc dl(N);
// FIXME: optimize the case where the src/dest is a load or store?
SDValue Store = CurDAG->getTruncStore(CurDAG->getEntryNode(), dl, N->getOperand(0),
MemTmp, MachinePointerInfo(), MemVT);
SDValue Result = CurDAG->getExtLoad(ISD::EXTLOAD, dl, DstVT, Store, MemTmp,
MachinePointerInfo(), MemVT);
// We're about to replace all uses of the FP_ROUND/FP_EXTEND with the
// extload we created. This will cause general havok on the dag because
// anything below the conversion could be folded into other existing nodes.
// To avoid invalidating 'I', back it up to the convert node.
--I;
CurDAG->ReplaceAllUsesOfValueWith(SDValue(N, 0), Result);
break;
}
//The sequence of events for lowering STRICT_FP versions of these nodes requires
//dealing with the chain differently, as there is already a preexisting chain.
case ISD::STRICT_FP_ROUND:
case ISD::STRICT_FP_EXTEND:
{
MVT SrcVT = N->getOperand(1).getSimpleValueType();
MVT DstVT = N->getSimpleValueType(0);
// If any of the sources are vectors, no fp stack involved.
if (SrcVT.isVector() || DstVT.isVector())
continue;
// If the source and destination are SSE registers, then this is a legal
// conversion that should not be lowered.
const X86TargetLowering *X86Lowering =
static_cast<const X86TargetLowering *>(TLI);
bool SrcIsSSE = X86Lowering->isScalarFPTypeInSSEReg(SrcVT);
bool DstIsSSE = X86Lowering->isScalarFPTypeInSSEReg(DstVT);
if (SrcIsSSE && DstIsSSE)
continue;
if (!SrcIsSSE && !DstIsSSE) {
// If this is an FPStack extension, it is a noop.
if (N->getOpcode() == ISD::STRICT_FP_EXTEND)
continue;
// If this is a value-preserving FPStack truncation, it is a noop.
if (N->getConstantOperandVal(2))
continue;
}
// Here we could have an FP stack truncation or an FPStack <-> SSE convert.
// FPStack has extload and truncstore. SSE can fold direct loads into other
// operations. Based on this, decide what we want to do.
MVT MemVT;
if (N->getOpcode() == ISD::STRICT_FP_ROUND)
MemVT = DstVT; // FP_ROUND must use DstVT, we can't do a 'trunc load'.
else
MemVT = SrcIsSSE ? SrcVT : DstVT;
SDValue MemTmp = CurDAG->CreateStackTemporary(MemVT);
SDLoc dl(N);
// FIXME: optimize the case where the src/dest is a load or store?
//Since the operation is StrictFP, use the preexisting chain.
SDValue Store = CurDAG->getTruncStore(N->getOperand(0), dl, N->getOperand(1),
MemTmp, MachinePointerInfo(), MemVT);
SDValue Result = CurDAG->getExtLoad(ISD::EXTLOAD, dl, DstVT, Store, MemTmp,
MachinePointerInfo(), MemVT);
// We're about to replace all uses of the FP_ROUND/FP_EXTEND with the
// extload we created. This will cause general havok on the dag because
// anything below the conversion could be folded into other existing nodes.
// To avoid invalidating 'I', back it up to the convert node.
--I;
CurDAG->ReplaceAllUsesWith(N, Result.getNode());
break;
}
}
// Now that we did that, the node is dead. Increment the iterator to the
// next node to process, then delete N.
++I;
CurDAG->DeleteNode(N);
}
// The load+call transform above can leave some dead nodes in the graph. Make
// sure we remove them. Its possible some of the other transforms do to so
// just remove dead nodes unconditionally.
CurDAG->RemoveDeadNodes();
}
// Look for a redundant movzx/movsx that can occur after an 8-bit divrem.
bool X86DAGToDAGISel::tryOptimizeRem8Extend(SDNode *N) {
unsigned Opc = N->getMachineOpcode();
if (Opc != X86::MOVZX32rr8 && Opc != X86::MOVSX32rr8 &&
Opc != X86::MOVSX64rr8)
return false;
SDValue N0 = N->getOperand(0);
// We need to be extracting the lower bit of an extend.
if (!N0.isMachineOpcode() ||
N0.getMachineOpcode() != TargetOpcode::EXTRACT_SUBREG ||
N0.getConstantOperandVal(1) != X86::sub_8bit)
return false;
// We're looking for either a movsx or movzx to match the original opcode.
unsigned ExpectedOpc = Opc == X86::MOVZX32rr8 ? X86::MOVZX32rr8_NOREX
: X86::MOVSX32rr8_NOREX;
SDValue N00 = N0.getOperand(0);
if (!N00.isMachineOpcode() || N00.getMachineOpcode() != ExpectedOpc)
return false;
if (Opc == X86::MOVSX64rr8) {
// If we had a sign extend from 8 to 64 bits. We still need to go from 32
// to 64.
MachineSDNode *Extend = CurDAG->getMachineNode(X86::MOVSX64rr32, SDLoc(N),
MVT::i64, N00);
ReplaceUses(N, Extend);
} else {
// Ok we can drop this extend and just use the original extend.
ReplaceUses(N, N00.getNode());
}
return true;
}
void X86DAGToDAGISel::PostprocessISelDAG() {
// Skip peepholes at -O0.
if (TM.getOptLevel() == CodeGenOpt::None)
return;
SelectionDAG::allnodes_iterator Position = CurDAG->allnodes_end();
bool MadeChange = false;
while (Position != CurDAG->allnodes_begin()) {
SDNode *N = &*--Position;
// Skip dead nodes and any non-machine opcodes.
if (N->use_empty() || !N->isMachineOpcode())
continue;
if (tryOptimizeRem8Extend(N)) {
MadeChange = true;
continue;
}
// Look for a TESTrr+ANDrr pattern where both operands of the test are
// the same. Rewrite to remove the AND.
unsigned Opc = N->getMachineOpcode();
if ((Opc == X86::TEST8rr || Opc == X86::TEST16rr ||
Opc == X86::TEST32rr || Opc == X86::TEST64rr) &&
N->getOperand(0) == N->getOperand(1) &&
N->isOnlyUserOf(N->getOperand(0).getNode()) &&
N->getOperand(0).isMachineOpcode()) {
SDValue And = N->getOperand(0);
unsigned N0Opc = And.getMachineOpcode();
if (N0Opc == X86::AND8rr || N0Opc == X86::AND16rr ||
N0Opc == X86::AND32rr || N0Opc == X86::AND64rr) {
MachineSDNode *Test = CurDAG->getMachineNode(Opc, SDLoc(N),
MVT::i32,
And.getOperand(0),
And.getOperand(1));
ReplaceUses(N, Test);
MadeChange = true;
continue;
}
if (N0Opc == X86::AND8rm || N0Opc == X86::AND16rm ||
N0Opc == X86::AND32rm || N0Opc == X86::AND64rm) {
unsigned NewOpc;
switch (N0Opc) {
case X86::AND8rm: NewOpc = X86::TEST8mr; break;
case X86::AND16rm: NewOpc = X86::TEST16mr; break;
case X86::AND32rm: NewOpc = X86::TEST32mr; break;
case X86::AND64rm: NewOpc = X86::TEST64mr; break;
}
// Need to swap the memory and register operand.
SDValue Ops[] = { And.getOperand(1),
And.getOperand(2),
And.getOperand(3),
And.getOperand(4),
And.getOperand(5),
And.getOperand(0),
And.getOperand(6) /* Chain */ };
MachineSDNode *Test = CurDAG->getMachineNode(NewOpc, SDLoc(N),
MVT::i32, MVT::Other, Ops);
ReplaceUses(N, Test);
MadeChange = true;
continue;
}
}
// Look for a KAND+KORTEST and turn it into KTEST if only the zero flag is
// used. We're doing this late so we can prefer to fold the AND into masked
// comparisons. Doing that can be better for the live range of the mask
// register.
if ((Opc == X86::KORTESTBrr || Opc == X86::KORTESTWrr ||
Opc == X86::KORTESTDrr || Opc == X86::KORTESTQrr) &&
N->getOperand(0) == N->getOperand(1) &&
N->isOnlyUserOf(N->getOperand(0).getNode()) &&
N->getOperand(0).isMachineOpcode() &&
onlyUsesZeroFlag(SDValue(N, 0))) {
SDValue And = N->getOperand(0);
unsigned N0Opc = And.getMachineOpcode();
// KANDW is legal with AVX512F, but KTESTW requires AVX512DQ. The other
// KAND instructions and KTEST use the same ISA feature.
if (N0Opc == X86::KANDBrr ||
(N0Opc == X86::KANDWrr && Subtarget->hasDQI()) ||
N0Opc == X86::KANDDrr || N0Opc == X86::KANDQrr) {
unsigned NewOpc;
switch (Opc) {
default: llvm_unreachable("Unexpected opcode!");
case X86::KORTESTBrr: NewOpc = X86::KTESTBrr; break;
case X86::KORTESTWrr: NewOpc = X86::KTESTWrr; break;
case X86::KORTESTDrr: NewOpc = X86::KTESTDrr; break;
case X86::KORTESTQrr: NewOpc = X86::KTESTQrr; break;
}
MachineSDNode *KTest = CurDAG->getMachineNode(NewOpc, SDLoc(N),
MVT::i32,
And.getOperand(0),
And.getOperand(1));
ReplaceUses(N, KTest);
MadeChange = true;
continue;
}
}
// Attempt to remove vectors moves that were inserted to zero upper bits.
if (Opc != TargetOpcode::SUBREG_TO_REG)
continue;
unsigned SubRegIdx = N->getConstantOperandVal(2);
if (SubRegIdx != X86::sub_xmm && SubRegIdx != X86::sub_ymm)
continue;
SDValue Move = N->getOperand(1);
if (!Move.isMachineOpcode())
continue;
// Make sure its one of the move opcodes we recognize.
switch (Move.getMachineOpcode()) {
default:
continue;
case X86::VMOVAPDrr: case X86::VMOVUPDrr:
case X86::VMOVAPSrr: case X86::VMOVUPSrr:
case X86::VMOVDQArr: case X86::VMOVDQUrr:
case X86::VMOVAPDYrr: case X86::VMOVUPDYrr:
case X86::VMOVAPSYrr: case X86::VMOVUPSYrr:
case X86::VMOVDQAYrr: case X86::VMOVDQUYrr:
case X86::VMOVAPDZ128rr: case X86::VMOVUPDZ128rr:
case X86::VMOVAPSZ128rr: case X86::VMOVUPSZ128rr:
case X86::VMOVDQA32Z128rr: case X86::VMOVDQU32Z128rr:
case X86::VMOVDQA64Z128rr: case X86::VMOVDQU64Z128rr:
case X86::VMOVAPDZ256rr: case X86::VMOVUPDZ256rr:
case X86::VMOVAPSZ256rr: case X86::VMOVUPSZ256rr:
case X86::VMOVDQA32Z256rr: case X86::VMOVDQU32Z256rr:
case X86::VMOVDQA64Z256rr: case X86::VMOVDQU64Z256rr:
break;
}
SDValue In = Move.getOperand(0);
if (!In.isMachineOpcode() ||
In.getMachineOpcode() <= TargetOpcode::GENERIC_OP_END)
continue;
// Make sure the instruction has a VEX, XOP, or EVEX prefix. This covers
// the SHA instructions which use a legacy encoding.
uint64_t TSFlags = getInstrInfo()->get(In.getMachineOpcode()).TSFlags;
if ((TSFlags & X86II::EncodingMask) != X86II::VEX &&
(TSFlags & X86II::EncodingMask) != X86II::EVEX &&
(TSFlags & X86II::EncodingMask) != X86II::XOP)
continue;
// Producing instruction is another vector instruction. We can drop the
// move.
CurDAG->UpdateNodeOperands(N, N->getOperand(0), In, N->getOperand(2));
MadeChange = true;
}
if (MadeChange)
CurDAG->RemoveDeadNodes();
}
/// Emit any code that needs to be executed only in the main function.
void X86DAGToDAGISel::emitSpecialCodeForMain() {
if (Subtarget->isTargetCygMing()) {
TargetLowering::ArgListTy Args;
auto &DL = CurDAG->getDataLayout();
TargetLowering::CallLoweringInfo CLI(*CurDAG);
CLI.setChain(CurDAG->getRoot())
.setCallee(CallingConv::C, Type::getVoidTy(*CurDAG->getContext()),
CurDAG->getExternalSymbol("__main", TLI->getPointerTy(DL)),
std::move(Args));
const TargetLowering &TLI = CurDAG->getTargetLoweringInfo();
std::pair<SDValue, SDValue> Result = TLI.LowerCallTo(CLI);
CurDAG->setRoot(Result.second);
}
}
void X86DAGToDAGISel::EmitFunctionEntryCode() {
// If this is main, emit special code for main.
const Function &F = MF->getFunction();
if (F.hasExternalLinkage() && F.getName() == "main")
emitSpecialCodeForMain();
}
static bool isDispSafeForFrameIndex(int64_t Val) {
// On 64-bit platforms, we can run into an issue where a frame index
// includes a displacement that, when added to the explicit displacement,
// will overflow the displacement field. Assuming that the frame index
// displacement fits into a 31-bit integer (which is only slightly more
// aggressive than the current fundamental assumption that it fits into
// a 32-bit integer), a 31-bit disp should always be safe.
return isInt<31>(Val);
}
bool X86DAGToDAGISel::foldOffsetIntoAddress(uint64_t Offset,
X86ISelAddressMode &AM) {
// If there's no offset to fold, we don't need to do any work.
if (Offset == 0)
return false;
// Cannot combine ExternalSymbol displacements with integer offsets.
if (AM.ES || AM.MCSym)
return true;
int64_t Val = AM.Disp + Offset;
CodeModel::Model M = TM.getCodeModel();
if (Subtarget->is64Bit()) {
if (!X86::isOffsetSuitableForCodeModel(Val, M,
AM.hasSymbolicDisplacement()))
return true;
// In addition to the checks required for a register base, check that
// we do not try to use an unsafe Disp with a frame index.
if (AM.BaseType == X86ISelAddressMode::FrameIndexBase &&
!isDispSafeForFrameIndex(Val))
return true;
}
AM.Disp = Val;
return false;
}
bool X86DAGToDAGISel::matchLoadInAddress(LoadSDNode *N, X86ISelAddressMode &AM){
SDValue Address = N->getOperand(1);
// load gs:0 -> GS segment register.
// load fs:0 -> FS segment register.
//
// This optimization is valid because the GNU TLS model defines that
// gs:0 (or fs:0 on X86-64) contains its own address.
// For more information see http://people.redhat.com/drepper/tls.pdf
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Address))
if (C->getSExtValue() == 0 && AM.Segment.getNode() == nullptr &&
!IndirectTlsSegRefs &&
(Subtarget->isTargetGlibc() || Subtarget->isTargetAndroid() ||
Subtarget->isTargetFuchsia()))
switch (N->getPointerInfo().getAddrSpace()) {
case 256:
AM.Segment = CurDAG->getRegister(X86::GS, MVT::i16);
return false;
case 257:
AM.Segment = CurDAG->getRegister(X86::FS, MVT::i16);
return false;
// Address space 258 is not handled here, because it is not used to
// address TLS areas.
}
return true;
}
/// Try to match X86ISD::Wrapper and X86ISD::WrapperRIP nodes into an addressing
/// mode. These wrap things that will resolve down into a symbol reference.
/// If no match is possible, this returns true, otherwise it returns false.
bool X86DAGToDAGISel::matchWrapper(SDValue N, X86ISelAddressMode &AM) {
// If the addressing mode already has a symbol as the displacement, we can
// never match another symbol.
if (AM.hasSymbolicDisplacement())
return true;
bool IsRIPRelTLS = false;
bool IsRIPRel = N.getOpcode() == X86ISD::WrapperRIP;
if (IsRIPRel) {
SDValue Val = N.getOperand(0);
if (Val.getOpcode() == ISD::TargetGlobalTLSAddress)
IsRIPRelTLS = true;
}
// We can't use an addressing mode in the 64-bit large code model.
// Global TLS addressing is an exception. In the medium code model,
// we use can use a mode when RIP wrappers are present.
// That signifies access to globals that are known to be "near",
// such as the GOT itself.
CodeModel::Model M = TM.getCodeModel();
if (Subtarget->is64Bit() &&
((M == CodeModel::Large && !IsRIPRelTLS) ||
(M == CodeModel::Medium && !IsRIPRel)))
return true;
// Base and index reg must be 0 in order to use %rip as base.
if (IsRIPRel && AM.hasBaseOrIndexReg())
return true;
// Make a local copy in case we can't do this fold.
X86ISelAddressMode Backup = AM;
int64_t Offset = 0;
SDValue N0 = N.getOperand(0);
if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(N0)) {
AM.GV = G->getGlobal();
AM.SymbolFlags = G->getTargetFlags();
Offset = G->getOffset();
} else if (ConstantPoolSDNode *CP = dyn_cast<ConstantPoolSDNode>(N0)) {
AM.CP = CP->getConstVal();
AM.Align = CP->getAlignment();
AM.SymbolFlags = CP->getTargetFlags();
Offset = CP->getOffset();
} else if (ExternalSymbolSDNode *S = dyn_cast<ExternalSymbolSDNode>(N0)) {
AM.ES = S->getSymbol();
AM.SymbolFlags = S->getTargetFlags();
} else if (auto *S = dyn_cast<MCSymbolSDNode>(N0)) {
AM.MCSym = S->getMCSymbol();
} else if (JumpTableSDNode *J = dyn_cast<JumpTableSDNode>(N0)) {
AM.JT = J->getIndex();
AM.SymbolFlags = J->getTargetFlags();
} else if (BlockAddressSDNode *BA = dyn_cast<BlockAddressSDNode>(N0)) {
AM.BlockAddr = BA->getBlockAddress();
AM.SymbolFlags = BA->getTargetFlags();
Offset = BA->getOffset();
} else
llvm_unreachable("Unhandled symbol reference node.");
if (foldOffsetIntoAddress(Offset, AM)) {
AM = Backup;
return true;
}
if (IsRIPRel)
AM.setBaseReg(CurDAG->getRegister(X86::RIP, MVT::i64));
// Commit the changes now that we know this fold is safe.
return false;
}
/// Add the specified node to the specified addressing mode, returning true if
/// it cannot be done. This just pattern matches for the addressing mode.
bool X86DAGToDAGISel::matchAddress(SDValue N, X86ISelAddressMode &AM) {
if (matchAddressRecursively(N, AM, 0))
return true;
// Post-processing: Convert lea(,%reg,2) to lea(%reg,%reg), which has
// a smaller encoding and avoids a scaled-index.
if (AM.Scale == 2 &&
AM.BaseType == X86ISelAddressMode::RegBase &&
AM.Base_Reg.getNode() == nullptr) {
AM.Base_Reg = AM.IndexReg;
AM.Scale = 1;
}
// Post-processing: Convert foo to foo(%rip), even in non-PIC mode,
// because it has a smaller encoding.
// TODO: Which other code models can use this?
switch (TM.getCodeModel()) {
default: break;
case CodeModel::Small:
case CodeModel::Kernel:
if (Subtarget->is64Bit() &&
AM.Scale == 1 &&
AM.BaseType == X86ISelAddressMode::RegBase &&
AM.Base_Reg.getNode() == nullptr &&
AM.IndexReg.getNode() == nullptr &&
AM.SymbolFlags == X86II::MO_NO_FLAG &&
AM.hasSymbolicDisplacement())
AM.Base_Reg = CurDAG->getRegister(X86::RIP, MVT::i64);
break;
}
return false;
}
bool X86DAGToDAGISel::matchAdd(SDValue &N, X86ISelAddressMode &AM,
unsigned Depth) {
// Add an artificial use to this node so that we can keep track of
// it if it gets CSE'd with a different node.
HandleSDNode Handle(N);
X86ISelAddressMode Backup = AM;
if (!matchAddressRecursively(N.getOperand(0), AM, Depth+1) &&
!matchAddressRecursively(Handle.getValue().getOperand(1), AM, Depth+1))
return false;
AM = Backup;
// Try again after commuting the operands.
if (!matchAddressRecursively(Handle.getValue().getOperand(1), AM, Depth+1) &&
!matchAddressRecursively(Handle.getValue().getOperand(0), AM, Depth+1))
return false;
AM = Backup;
// If we couldn't fold both operands into the address at the same time,
// see if we can just put each operand into a register and fold at least
// the add.
if (AM.BaseType == X86ISelAddressMode::RegBase &&
!AM.Base_Reg.getNode() &&
!AM.IndexReg.getNode()) {
N = Handle.getValue();
AM.Base_Reg = N.getOperand(0);
AM.IndexReg = N.getOperand(1);
AM.Scale = 1;
return false;
}
N = Handle.getValue();
return true;
}
// Insert a node into the DAG at least before the Pos node's position. This
// will reposition the node as needed, and will assign it a node ID that is <=
// the Pos node's ID. Note that this does *not* preserve the uniqueness of node
// IDs! The selection DAG must no longer depend on their uniqueness when this
// is used.
static void insertDAGNode(SelectionDAG &DAG, SDValue Pos, SDValue N) {
if (N->getNodeId() == -1 ||
(SelectionDAGISel::getUninvalidatedNodeId(N.getNode()) >
SelectionDAGISel::getUninvalidatedNodeId(Pos.getNode()))) {
DAG.RepositionNode(Pos->getIterator(), N.getNode());
// Mark Node as invalid for pruning as after this it may be a successor to a
// selected node but otherwise be in the same position of Pos.
// Conservatively mark it with the same -abs(Id) to assure node id
// invariant is preserved.
N->setNodeId(Pos->getNodeId());
SelectionDAGISel::InvalidateNodeId(N.getNode());
}
}
// Transform "(X >> (8-C1)) & (0xff << C1)" to "((X >> 8) & 0xff) << C1" if
// safe. This allows us to convert the shift and and into an h-register
// extract and a scaled index. Returns false if the simplification is
// performed.
static bool foldMaskAndShiftToExtract(SelectionDAG &DAG, SDValue N,
uint64_t Mask,
SDValue Shift, SDValue X,
X86ISelAddressMode &AM) {
if (Shift.getOpcode() != ISD::SRL ||
!isa<ConstantSDNode>(Shift.getOperand(1)) ||
!Shift.hasOneUse())
return true;
int ScaleLog = 8 - Shift.getConstantOperandVal(1);
if (ScaleLog <= 0 || ScaleLog >= 4 ||
Mask != (0xffu << ScaleLog))
return true;
MVT VT = N.getSimpleValueType();
SDLoc DL(N);
SDValue Eight = DAG.getConstant(8, DL, MVT::i8);
SDValue NewMask = DAG.getConstant(0xff, DL, VT);
SDValue Srl = DAG.getNode(ISD::SRL, DL, VT, X, Eight);
SDValue And = DAG.getNode(ISD::AND, DL, VT, Srl, NewMask);
SDValue ShlCount = DAG.getConstant(ScaleLog, DL, MVT::i8);
SDValue Shl = DAG.getNode(ISD::SHL, DL, VT, And, ShlCount);
// Insert the new nodes into the topological ordering. We must do this in
// a valid topological ordering as nothing is going to go back and re-sort
// these nodes. We continually insert before 'N' in sequence as this is
// essentially a pre-flattened and pre-sorted sequence of nodes. There is no
// hierarchy left to express.
insertDAGNode(DAG, N, Eight);
insertDAGNode(DAG, N, Srl);
insertDAGNode(DAG, N, NewMask);
insertDAGNode(DAG, N, And);
insertDAGNode(DAG, N, ShlCount);
insertDAGNode(DAG, N, Shl);
DAG.ReplaceAllUsesWith(N, Shl);
DAG.RemoveDeadNode(N.getNode());
AM.IndexReg = And;
AM.Scale = (1 << ScaleLog);
return false;
}
// Transforms "(X << C1) & C2" to "(X & (C2>>C1)) << C1" if safe and if this
// allows us to fold the shift into this addressing mode. Returns false if the
// transform succeeded.
static bool foldMaskedShiftToScaledMask(SelectionDAG &DAG, SDValue N,
X86ISelAddressMode &AM) {
SDValue Shift = N.getOperand(0);
// Use a signed mask so that shifting right will insert sign bits. These
// bits will be removed when we shift the result left so it doesn't matter
// what we use. This might allow a smaller immediate encoding.
int64_t Mask = cast<ConstantSDNode>(N->getOperand(1))->getSExtValue();
// If we have an any_extend feeding the AND, look through it to see if there
// is a shift behind it. But only if the AND doesn't use the extended bits.
// FIXME: Generalize this to other ANY_EXTEND than i32 to i64?
bool FoundAnyExtend = false;
if (Shift.getOpcode() == ISD::ANY_EXTEND && Shift.hasOneUse() &&
Shift.getOperand(0).getSimpleValueType() == MVT::i32 &&
isUInt<32>(Mask)) {
FoundAnyExtend = true;
Shift = Shift.getOperand(0);
}
if (Shift.getOpcode() != ISD::SHL ||
!isa<ConstantSDNode>(Shift.getOperand(1)))
return true;
SDValue X = Shift.getOperand(0);
// Not likely to be profitable if either the AND or SHIFT node has more
// than one use (unless all uses are for address computation). Besides,
// isel mechanism requires their node ids to be reused.
if (!N.hasOneUse() || !Shift.hasOneUse())
return true;
// Verify that the shift amount is something we can fold.
unsigned ShiftAmt = Shift.getConstantOperandVal(1);
if (ShiftAmt != 1 && ShiftAmt != 2 && ShiftAmt != 3)
return true;
MVT VT = N.getSimpleValueType();
SDLoc DL(N);
if (FoundAnyExtend) {
SDValue NewX = DAG.getNode(ISD::ANY_EXTEND, DL, VT, X);
insertDAGNode(DAG, N, NewX);
X = NewX;
}
SDValue NewMask = DAG.getConstant(Mask >> ShiftAmt, DL, VT);
SDValue NewAnd = DAG.getNode(ISD::AND, DL, VT, X, NewMask);
SDValue NewShift = DAG.getNode(ISD::SHL, DL, VT, NewAnd, Shift.getOperand(1));
// Insert the new nodes into the topological ordering. We must do this in
// a valid topological ordering as nothing is going to go back and re-sort
// these nodes. We continually insert before 'N' in sequence as this is
// essentially a pre-flattened and pre-sorted sequence of nodes. There is no
// hierarchy left to express.
insertDAGNode(DAG, N, NewMask);
insertDAGNode(DAG, N, NewAnd);
insertDAGNode(DAG, N, NewShift);
DAG.ReplaceAllUsesWith(N, NewShift);
DAG.RemoveDeadNode(N.getNode());
AM.Scale = 1 << ShiftAmt;
AM.IndexReg = NewAnd;
return false;
}
// Implement some heroics to detect shifts of masked values where the mask can
// be replaced by extending the shift and undoing that in the addressing mode
// scale. Patterns such as (shl (srl x, c1), c2) are canonicalized into (and
// (srl x, SHIFT), MASK) by DAGCombines that don't know the shl can be done in
// the addressing mode. This results in code such as:
//
// int f(short *y, int *lookup_table) {
// ...
// return *y + lookup_table[*y >> 11];
// }
//
// Turning into:
// movzwl (%rdi), %eax
// movl %eax, %ecx
// shrl $11, %ecx
// addl (%rsi,%rcx,4), %eax
//
// Instead of:
// movzwl (%rdi), %eax
// movl %eax, %ecx
// shrl $9, %ecx
// andl $124, %rcx
// addl (%rsi,%rcx), %eax
//
// Note that this function assumes the mask is provided as a mask *after* the
// value is shifted. The input chain may or may not match that, but computing
// such a mask is trivial.
static bool foldMaskAndShiftToScale(SelectionDAG &DAG, SDValue N,
uint64_t Mask,
SDValue Shift, SDValue X,
X86ISelAddressMode &AM) {
if (Shift.getOpcode() != ISD::SRL || !Shift.hasOneUse() ||
!isa<ConstantSDNode>(Shift.getOperand(1)))
return true;
unsigned ShiftAmt = Shift.getConstantOperandVal(1);
unsigned MaskLZ = countLeadingZeros(Mask);
unsigned MaskTZ = countTrailingZeros(Mask);
// The amount of shift we're trying to fit into the addressing mode is taken
// from the trailing zeros of the mask.
unsigned AMShiftAmt = MaskTZ;
// There is nothing we can do here unless the mask is removing some bits.
// Also, the addressing mode can only represent shifts of 1, 2, or 3 bits.
if (AMShiftAmt <= 0 || AMShiftAmt > 3) return true;
// We also need to ensure that mask is a continuous run of bits.
if (countTrailingOnes(Mask >> MaskTZ) + MaskTZ + MaskLZ != 64) return true;
// Scale the leading zero count down based on the actual size of the value.
// Also scale it down based on the size of the shift.
unsigned ScaleDown = (64 - X.getSimpleValueType().getSizeInBits()) + ShiftAmt;
if (MaskLZ < ScaleDown)
return true;
MaskLZ -= ScaleDown;
// The final check is to ensure that any masked out high bits of X are
// already known to be zero. Otherwise, the mask has a semantic impact
// other than masking out a couple of low bits. Unfortunately, because of
// the mask, zero extensions will be removed from operands in some cases.
// This code works extra hard to look through extensions because we can
// replace them with zero extensions cheaply if necessary.
bool ReplacingAnyExtend = false;
if (X.getOpcode() == ISD::ANY_EXTEND) {
unsigned ExtendBits = X.getSimpleValueType().getSizeInBits() -
X.getOperand(0).getSimpleValueType().getSizeInBits();
// Assume that we'll replace the any-extend with a zero-extend, and
// narrow the search to the extended value.
X = X.getOperand(0);
MaskLZ = ExtendBits > MaskLZ ? 0 : MaskLZ - ExtendBits;
ReplacingAnyExtend = true;
}
APInt MaskedHighBits =
APInt::getHighBitsSet(X.getSimpleValueType().getSizeInBits(), MaskLZ);
KnownBits Known = DAG.computeKnownBits(X);
if (MaskedHighBits != Known.Zero) return true;
// We've identified a pattern that can be transformed into a single shift
// and an addressing mode. Make it so.
MVT VT = N.getSimpleValueType();
if (ReplacingAnyExtend) {
assert(X.getValueType() != VT);
// We looked through an ANY_EXTEND node, insert a ZERO_EXTEND.
SDValue NewX = DAG.getNode(ISD::ZERO_EXTEND, SDLoc(X), VT, X);
insertDAGNode(DAG, N, NewX);
X = NewX;
}
SDLoc DL(N);
SDValue NewSRLAmt = DAG.getConstant(ShiftAmt + AMShiftAmt, DL, MVT::i8);
SDValue NewSRL = DAG.getNode(ISD::SRL, DL, VT, X, NewSRLAmt);
SDValue NewSHLAmt = DAG.getConstant(AMShiftAmt, DL, MVT::i8);
SDValue NewSHL = DAG.getNode(ISD::SHL, DL, VT, NewSRL, NewSHLAmt);
// Insert the new nodes into the topological ordering. We must do this in
// a valid topological ordering as nothing is going to go back and re-sort
// these nodes. We continually insert before 'N' in sequence as this is
// essentially a pre-flattened and pre-sorted sequence of nodes. There is no
// hierarchy left to express.
insertDAGNode(DAG, N, NewSRLAmt);
insertDAGNode(DAG, N, NewSRL);
insertDAGNode(DAG, N, NewSHLAmt);
insertDAGNode(DAG, N, NewSHL);
DAG.ReplaceAllUsesWith(N, NewSHL);
DAG.RemoveDeadNode(N.getNode());
AM.Scale = 1 << AMShiftAmt;
AM.IndexReg = NewSRL;
return false;
}
// Transform "(X >> SHIFT) & (MASK << C1)" to
// "((X >> (SHIFT + C1)) & (MASK)) << C1". Everything before the SHL will be
// matched to a BEXTR later. Returns false if the simplification is performed.
static bool foldMaskedShiftToBEXTR(SelectionDAG &DAG, SDValue N,
uint64_t Mask,
SDValue Shift, SDValue X,
X86ISelAddressMode &AM,
const X86Subtarget &Subtarget) {
if (Shift.getOpcode() != ISD::SRL ||
!isa<ConstantSDNode>(Shift.getOperand(1)) ||
!Shift.hasOneUse() || !N.hasOneUse())
return true;
// Only do this if BEXTR will be matched by matchBEXTRFromAndImm.
if (!Subtarget.hasTBM() &&
!(Subtarget.hasBMI() && Subtarget.hasFastBEXTR()))
return true;
// We need to ensure that mask is a continuous run of bits.
if (!isShiftedMask_64(Mask)) return true;
unsigned ShiftAmt = Shift.getConstantOperandVal(1);
// The amount of shift we're trying to fit into the addressing mode is taken
// from the trailing zeros of the mask.
unsigned AMShiftAmt = countTrailingZeros(Mask);
// There is nothing we can do here unless the mask is removing some bits.
// Also, the addressing mode can only represent shifts of 1, 2, or 3 bits.
if (AMShiftAmt <= 0 || AMShiftAmt > 3) return true;
MVT VT = N.getSimpleValueType();
SDLoc DL(N);
SDValue NewSRLAmt = DAG.getConstant(ShiftAmt + AMShiftAmt, DL, MVT::i8);
SDValue NewSRL = DAG.getNode(ISD::SRL, DL, VT, X, NewSRLAmt);
SDValue NewMask = DAG.getConstant(Mask >> AMShiftAmt, DL, VT);
SDValue NewAnd = DAG.getNode(ISD::AND, DL, VT, NewSRL, NewMask);
SDValue NewSHLAmt = DAG.getConstant(AMShiftAmt, DL, MVT::i8);
SDValue NewSHL = DAG.getNode(ISD::SHL, DL, VT, NewAnd, NewSHLAmt);
// Insert the new nodes into the topological ordering. We must do this in
// a valid topological ordering as nothing is going to go back and re-sort
// these nodes. We continually insert before 'N' in sequence as this is
// essentially a pre-flattened and pre-sorted sequence of nodes. There is no
// hierarchy left to express.
insertDAGNode(DAG, N, NewSRLAmt);
insertDAGNode(DAG, N, NewSRL);
insertDAGNode(DAG, N, NewMask);
insertDAGNode(DAG, N, NewAnd);
insertDAGNode(DAG, N, NewSHLAmt);
insertDAGNode(DAG, N, NewSHL);
DAG.ReplaceAllUsesWith(N, NewSHL);
DAG.RemoveDeadNode(N.getNode());
AM.Scale = 1 << AMShiftAmt;
AM.IndexReg = NewAnd;
return false;
}
bool X86DAGToDAGISel::matchAddressRecursively(SDValue N, X86ISelAddressMode &AM,
unsigned Depth) {
SDLoc dl(N);
LLVM_DEBUG({
dbgs() << "MatchAddress: ";
AM.dump(CurDAG);
});
// Limit recursion.
if (Depth > 5)
return matchAddressBase(N, AM);
// If this is already a %rip relative address, we can only merge immediates
// into it. Instead of handling this in every case, we handle it here.
// RIP relative addressing: %rip + 32-bit displacement!
if (AM.isRIPRelative()) {
// FIXME: JumpTable and ExternalSymbol address currently don't like
// displacements. It isn't very important, but this should be fixed for
// consistency.
if (!(AM.ES || AM.MCSym) && AM.JT != -1)
return true;
if (ConstantSDNode *Cst = dyn_cast<ConstantSDNode>(N))
if (!foldOffsetIntoAddress(Cst->getSExtValue(), AM))
return false;
return true;
}
switch (N.getOpcode()) {
default: break;
case ISD::LOCAL_RECOVER: {
if (!AM.hasSymbolicDisplacement() && AM.Disp == 0)
if (const auto *ESNode = dyn_cast<MCSymbolSDNode>(N.getOperand(0))) {
// Use the symbol and don't prefix it.
AM.MCSym = ESNode->getMCSymbol();
return false;
}
break;
}
case ISD::Constant: {
uint64_t Val = cast<ConstantSDNode>(N)->getSExtValue();
if (!foldOffsetIntoAddress(Val, AM))
return false;
break;
}
case X86ISD::Wrapper:
case X86ISD::WrapperRIP:
if (!matchWrapper(N, AM))
return false;
break;
case ISD::LOAD:
if (!matchLoadInAddress(cast<LoadSDNode>(N), AM))
return false;
break;
case ISD::FrameIndex:
if (AM.BaseType == X86ISelAddressMode::RegBase &&
AM.Base_Reg.getNode() == nullptr &&
(!Subtarget->is64Bit() || isDispSafeForFrameIndex(AM.Disp))) {
AM.BaseType = X86ISelAddressMode::FrameIndexBase;
AM.Base_FrameIndex = cast<FrameIndexSDNode>(N)->getIndex();
return false;
}
break;
case ISD::SHL:
if (AM.IndexReg.getNode() != nullptr || AM.Scale != 1)
break;
if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N.getOperand(1))) {
unsigned Val = CN->getZExtValue();
// Note that we handle x<<1 as (,x,2) rather than (x,x) here so
// that the base operand remains free for further matching. If
// the base doesn't end up getting used, a post-processing step
// in MatchAddress turns (,x,2) into (x,x), which is cheaper.
if (Val == 1 || Val == 2 || Val == 3) {
AM.Scale = 1 << Val;
SDValue ShVal = N.getOperand(0);
// Okay, we know that we have a scale by now. However, if the scaled
// value is an add of something and a constant, we can fold the
// constant into the disp field here.
if (CurDAG->isBaseWithConstantOffset(ShVal)) {
AM.IndexReg = ShVal.getOperand(0);
ConstantSDNode *AddVal = cast<ConstantSDNode>(ShVal.getOperand(1));
uint64_t Disp = (uint64_t)AddVal->getSExtValue() << Val;
if (!foldOffsetIntoAddress(Disp, AM))
return false;
}
AM.IndexReg = ShVal;
return false;
}
}
break;
case ISD::SRL: {
// Scale must not be used already.
if (AM.IndexReg.getNode() != nullptr || AM.Scale != 1) break;
// We only handle up to 64-bit values here as those are what matter for
// addressing mode optimizations.
assert(N.getSimpleValueType().getSizeInBits() <= 64 &&
"Unexpected value size!");
SDValue And = N.getOperand(0);
if (And.getOpcode() != ISD::AND) break;
SDValue X = And.getOperand(0);
// The mask used for the transform is expected to be post-shift, but we
// found the shift first so just apply the shift to the mask before passing
// it down.
if (!isa<ConstantSDNode>(N.getOperand(1)) ||
!isa<ConstantSDNode>(And.getOperand(1)))
break;
uint64_t Mask = And.getConstantOperandVal(1) >> N.getConstantOperandVal(1);
// Try to fold the mask and shift into the scale, and return false if we
// succeed.
if (!foldMaskAndShiftToScale(*CurDAG, N, Mask, N, X, AM))
return false;
break;
}
case ISD::SMUL_LOHI:
case ISD::UMUL_LOHI:
// A mul_lohi where we need the low part can be folded as a plain multiply.
if (N.getResNo() != 0) break;
LLVM_FALLTHROUGH;
case ISD::MUL:
case X86ISD::MUL_IMM:
// X*[3,5,9] -> X+X*[2,4,8]
if (AM.BaseType == X86ISelAddressMode::RegBase &&
AM.Base_Reg.getNode() == nullptr &&
AM.IndexReg.getNode() == nullptr) {
if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N.getOperand(1)))
if (CN->getZExtValue() == 3 || CN->getZExtValue() == 5 ||
CN->getZExtValue() == 9) {
AM.Scale = unsigned(CN->getZExtValue())-1;
SDValue MulVal = N.getOperand(0);
SDValue Reg;
// Okay, we know that we have a scale by now. However, if the scaled
// value is an add of something and a constant, we can fold the
// constant into the disp field here.
if (MulVal.getNode()->getOpcode() == ISD::ADD && MulVal.hasOneUse() &&
isa<ConstantSDNode>(MulVal.getOperand(1))) {
Reg = MulVal.getOperand(0);
ConstantSDNode *AddVal =
cast<ConstantSDNode>(MulVal.getOperand(1));
uint64_t Disp = AddVal->getSExtValue() * CN->getZExtValue();
if (foldOffsetIntoAddress(Disp, AM))
Reg = N.getOperand(0);
} else {
Reg = N.getOperand(0);
}
AM.IndexReg = AM.Base_Reg = Reg;
return false;
}
}
break;
case ISD::SUB: {
// Given A-B, if A can be completely folded into the address and
// the index field with the index field unused, use -B as the index.
// This is a win if a has multiple parts that can be folded into
// the address. Also, this saves a mov if the base register has
// other uses, since it avoids a two-address sub instruction, however
// it costs an additional mov if the index register has other uses.
// Add an artificial use to this node so that we can keep track of
// it if it gets CSE'd with a different node.
HandleSDNode Handle(N);
// Test if the LHS of the sub can be folded.
X86ISelAddressMode Backup = AM;
if (matchAddressRecursively(N.getOperand(0), AM, Depth+1)) {
N = Handle.getValue();
AM = Backup;
break;
}
N = Handle.getValue();
// Test if the index field is free for use.
if (AM.IndexReg.getNode() || AM.isRIPRelative()) {
AM = Backup;
break;
}
int Cost = 0;
SDValue RHS = N.getOperand(1);
// If the RHS involves a register with multiple uses, this
// transformation incurs an extra mov, due to the neg instruction
// clobbering its operand.
if (!RHS.getNode()->hasOneUse() ||
RHS.getNode()->getOpcode() == ISD::CopyFromReg ||
RHS.getNode()->getOpcode() == ISD::TRUNCATE ||
RHS.getNode()->getOpcode() == ISD::ANY_EXTEND ||
(RHS.getNode()->getOpcode() == ISD::ZERO_EXTEND &&
RHS.getOperand(0).getValueType() == MVT::i32))
++Cost;
// If the base is a register with multiple uses, this
// transformation may save a mov.
if ((AM.BaseType == X86ISelAddressMode::RegBase && AM.Base_Reg.getNode() &&
!AM.Base_Reg.getNode()->hasOneUse()) ||
AM.BaseType == X86ISelAddressMode::FrameIndexBase)
--Cost;
// If the folded LHS was interesting, this transformation saves
// address arithmetic.
if ((AM.hasSymbolicDisplacement() && !Backup.hasSymbolicDisplacement()) +
((AM.Disp != 0) && (Backup.Disp == 0)) +
(AM.Segment.getNode() && !Backup.Segment.getNode()) >= 2)
--Cost;
// If it doesn't look like it may be an overall win, don't do it.
if (Cost >= 0) {
AM = Backup;
break;
}
// Ok, the transformation is legal and appears profitable. Go for it.
// Negation will be emitted later to avoid creating dangling nodes if this
// was an unprofitable LEA.
AM.IndexReg = RHS;
AM.NegateIndex = true;
AM.Scale = 1;
return false;
}
case ISD::ADD:
if (!matchAdd(N, AM, Depth))
return false;
break;
case ISD::OR:
// We want to look through a transform in InstCombine and DAGCombiner that
// turns 'add' into 'or', so we can treat this 'or' exactly like an 'add'.
// Example: (or (and x, 1), (shl y, 3)) --> (add (and x, 1), (shl y, 3))
// An 'lea' can then be used to match the shift (multiply) and add:
// and $1, %esi
// lea (%rsi, %rdi, 8), %rax
if (CurDAG->haveNoCommonBitsSet(N.getOperand(0), N.getOperand(1)) &&
!matchAdd(N, AM, Depth))
return false;
break;
case ISD::AND: {
// Perform some heroic transforms on an and of a constant-count shift
// with a constant to enable use of the scaled offset field.
// Scale must not be used already.
if (AM.IndexReg.getNode() != nullptr || AM.Scale != 1) break;
// We only handle up to 64-bit values here as those are what matter for
// addressing mode optimizations.
assert(N.getSimpleValueType().getSizeInBits() <= 64 &&
"Unexpected value size!");
if (!isa<ConstantSDNode>(N.getOperand(1)))
break;
if (N.getOperand(0).getOpcode() == ISD::SRL) {
SDValue Shift = N.getOperand(0);
SDValue X = Shift.getOperand(0);
uint64_t Mask = N.getConstantOperandVal(1);
// Try to fold the mask and shift into an extract and scale.
if (!foldMaskAndShiftToExtract(*CurDAG, N, Mask, Shift, X, AM))
return false;
// Try to fold the mask and shift directly into the scale.
if (!foldMaskAndShiftToScale(*CurDAG, N, Mask, Shift, X, AM))
return false;
// Try to fold the mask and shift into BEXTR and scale.
if (!foldMaskedShiftToBEXTR(*CurDAG, N, Mask, Shift, X, AM, *Subtarget))
return false;
}
// Try to swap the mask and shift to place shifts which can be done as
// a scale on the outside of the mask.
if (!foldMaskedShiftToScaledMask(*CurDAG, N, AM))
return false;
break;
}
case ISD::ZERO_EXTEND: {
// Try to widen a zexted shift left to the same size as its use, so we can
// match the shift as a scale factor.
if (AM.IndexReg.getNode() != nullptr || AM.Scale != 1)
break;
if (N.getOperand(0).getOpcode() != ISD::SHL || !N.getOperand(0).hasOneUse())
break;
// Give up if the shift is not a valid scale factor [1,2,3].
SDValue Shl = N.getOperand(0);
auto *ShAmtC = dyn_cast<ConstantSDNode>(Shl.getOperand(1));
if (!ShAmtC || ShAmtC->getZExtValue() > 3)
break;
// The narrow shift must only shift out zero bits (it must be 'nuw').
// That makes it safe to widen to the destination type.
APInt HighZeros = APInt::getHighBitsSet(Shl.getValueSizeInBits(),
ShAmtC->getZExtValue());
if (!CurDAG->MaskedValueIsZero(Shl.getOperand(0), HighZeros))
break;
// zext (shl nuw i8 %x, C) to i32 --> shl (zext i8 %x to i32), (zext C)
MVT VT = N.getSimpleValueType();
SDLoc DL(N);
SDValue Zext = CurDAG->getNode(ISD::ZERO_EXTEND, DL, VT, Shl.getOperand(0));
SDValue NewShl = CurDAG->getNode(ISD::SHL, DL, VT, Zext, Shl.getOperand(1));
// Convert the shift to scale factor.
AM.Scale = 1 << ShAmtC->getZExtValue();
AM.IndexReg = Zext;
insertDAGNode(*CurDAG, N, Zext);
insertDAGNode(*CurDAG, N, NewShl);
CurDAG->ReplaceAllUsesWith(N, NewShl);
CurDAG->RemoveDeadNode(N.getNode());
return false;
}
}
return matchAddressBase(N, AM);
}
/// Helper for MatchAddress. Add the specified node to the
/// specified addressing mode without any further recursion.
bool X86DAGToDAGISel::matchAddressBase(SDValue N, X86ISelAddressMode &AM) {
// Is the base register already occupied?
if (AM.BaseType != X86ISelAddressMode::RegBase || AM.Base_Reg.getNode()) {
// If so, check to see if the scale index register is set.
if (!AM.IndexReg.getNode()) {
AM.IndexReg = N;
AM.Scale = 1;
return false;
}
// Otherwise, we cannot select it.
return true;
}
// Default, generate it as a register.
AM.BaseType = X86ISelAddressMode::RegBase;
AM.Base_Reg = N;
return false;
}
/// Helper for selectVectorAddr. Handles things that can be folded into a
/// gather scatter address. The index register and scale should have already
/// been handled.
bool X86DAGToDAGISel::matchVectorAddress(SDValue N, X86ISelAddressMode &AM) {
// TODO: Support other operations.
switch (N.getOpcode()) {
case ISD::Constant: {
uint64_t Val = cast<ConstantSDNode>(N)->getSExtValue();
if (!foldOffsetIntoAddress(Val, AM))
return false;
break;
}
case X86ISD::Wrapper:
if (!matchWrapper(N, AM))
return false;
break;
}
return matchAddressBase(N, AM);
}
bool X86DAGToDAGISel::selectVectorAddr(SDNode *Parent, SDValue N, SDValue &Base,
SDValue &Scale, SDValue &Index,
SDValue &Disp, SDValue &Segment) {
X86ISelAddressMode AM;
auto *Mgs = cast<X86MaskedGatherScatterSDNode>(Parent);
AM.IndexReg = Mgs->getIndex();
AM.Scale = cast<ConstantSDNode>(Mgs->getScale())->getZExtValue();
unsigned AddrSpace = cast<MemSDNode>(Parent)->getPointerInfo().getAddrSpace();
// AddrSpace 256 -> GS, 257 -> FS, 258 -> SS.
if (AddrSpace == 256)
AM.Segment = CurDAG->getRegister(X86::GS, MVT::i16);
if (AddrSpace == 257)
AM.Segment = CurDAG->getRegister(X86::FS, MVT::i16);
if (AddrSpace == 258)
AM.Segment = CurDAG->getRegister(X86::SS, MVT::i16);
SDLoc DL(N);
MVT VT = N.getSimpleValueType();
// Try to match into the base and displacement fields.
if (matchVectorAddress(N, AM))
return false;
getAddressOperands(AM, DL, VT, Base, Scale, Index, Disp, Segment);
return true;
}
/// Returns true if it is able to pattern match an addressing mode.
/// It returns the operands which make up the maximal addressing mode it can
/// match by reference.
///
/// Parent is the parent node of the addr operand that is being matched. It
/// is always a load, store, atomic node, or null. It is only null when
/// checking memory operands for inline asm nodes.
bool X86DAGToDAGISel::selectAddr(SDNode *Parent, SDValue N, SDValue &Base,
SDValue &Scale, SDValue &Index,
SDValue &Disp, SDValue &Segment) {
X86ISelAddressMode AM;
if (Parent &&
// This list of opcodes are all the nodes that have an "addr:$ptr" operand
// that are not a MemSDNode, and thus don't have proper addrspace info.
Parent->getOpcode() != ISD::INTRINSIC_W_CHAIN && // unaligned loads, fixme
Parent->getOpcode() != ISD::INTRINSIC_VOID && // nontemporal stores
Parent->getOpcode() != X86ISD::TLSCALL && // Fixme
Parent->getOpcode() != X86ISD::ENQCMD && // Fixme
Parent->getOpcode() != X86ISD::ENQCMDS && // Fixme
Parent->getOpcode() != X86ISD::EH_SJLJ_SETJMP && // setjmp
Parent->getOpcode() != X86ISD::EH_SJLJ_LONGJMP) { // longjmp
unsigned AddrSpace =
cast<MemSDNode>(Parent)->getPointerInfo().getAddrSpace();
// AddrSpace 256 -> GS, 257 -> FS, 258 -> SS.
if (AddrSpace == 256)
AM.Segment = CurDAG->getRegister(X86::GS, MVT::i16);
if (AddrSpace == 257)
AM.Segment = CurDAG->getRegister(X86::FS, MVT::i16);
if (AddrSpace == 258)
AM.Segment = CurDAG->getRegister(X86::SS, MVT::i16);
}
// Save the DL and VT before calling matchAddress, it can invalidate N.
SDLoc DL(N);
MVT VT = N.getSimpleValueType();
if (matchAddress(N, AM))
return false;
getAddressOperands(AM, DL, VT, Base, Scale, Index, Disp, Segment);
return true;
}
// We can only fold a load if all nodes between it and the root node have a
// single use. If there are additional uses, we could end up duplicating the
// load.
static bool hasSingleUsesFromRoot(SDNode *Root, SDNode *User) {
while (User != Root) {
if (!User->hasOneUse())
return false;
User = *User->use_begin();
}
return true;
}
/// Match a scalar SSE load. In particular, we want to match a load whose top
/// elements are either undef or zeros. The load flavor is derived from the
/// type of N, which is either v4f32 or v2f64.
///
/// We also return:
/// PatternChainNode: this is the matched node that has a chain input and
/// output.
bool X86DAGToDAGISel::selectScalarSSELoad(SDNode *Root, SDNode *Parent,
SDValue N, SDValue &Base,
SDValue &Scale, SDValue &Index,
SDValue &Disp, SDValue &Segment,
SDValue &PatternNodeWithChain) {
if (!hasSingleUsesFromRoot(Root, Parent))
return false;
// We can allow a full vector load here since narrowing a load is ok unless
// it's volatile.
if (ISD::isNON_EXTLoad(N.getNode())) {
LoadSDNode *LD = cast<LoadSDNode>(N);
if (!LD->isVolatile() &&
IsProfitableToFold(N, LD, Root) &&
IsLegalToFold(N, Parent, Root, OptLevel)) {
PatternNodeWithChain = N;
return selectAddr(LD, LD->getBasePtr(), Base, Scale, Index, Disp,
Segment);
}
}
// We can also match the special zero extended load opcode.
if (N.getOpcode() == X86ISD::VZEXT_LOAD) {
PatternNodeWithChain = N;
if (IsProfitableToFold(PatternNodeWithChain, N.getNode(), Root) &&
IsLegalToFold(PatternNodeWithChain, Parent, Root, OptLevel)) {
auto *MI = cast<MemIntrinsicSDNode>(PatternNodeWithChain);
return selectAddr(MI, MI->getBasePtr(), Base, Scale, Index, Disp,
Segment);
}
}
// Need to make sure that the SCALAR_TO_VECTOR and load are both only used
// once. Otherwise the load might get duplicated and the chain output of the
// duplicate load will not be observed by all dependencies.
if (N.getOpcode() == ISD::SCALAR_TO_VECTOR && N.getNode()->hasOneUse()) {
PatternNodeWithChain = N.getOperand(0);
if (ISD::isNON_EXTLoad(PatternNodeWithChain.getNode()) &&
IsProfitableToFold(PatternNodeWithChain, N.getNode(), Root) &&
IsLegalToFold(PatternNodeWithChain, N.getNode(), Root, OptLevel)) {
LoadSDNode *LD = cast<LoadSDNode>(PatternNodeWithChain);
return selectAddr(LD, LD->getBasePtr(), Base, Scale, Index, Disp,
Segment);
}
}
return false;
}
bool X86DAGToDAGISel::selectMOV64Imm32(SDValue N, SDValue &Imm) {
if (const ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N)) {
uint64_t ImmVal = CN->getZExtValue();
if (!isUInt<32>(ImmVal))
return false;
Imm = CurDAG->getTargetConstant(ImmVal, SDLoc(N), MVT::i64);
return true;
}
// In static codegen with small code model, we can get the address of a label
// into a register with 'movl'
if (N->getOpcode() != X86ISD::Wrapper)
return false;
N = N.getOperand(0);
// At least GNU as does not accept 'movl' for TPOFF relocations.
// FIXME: We could use 'movl' when we know we are targeting MC.
if (N->getOpcode() == ISD::TargetGlobalTLSAddress)
return false;
Imm = N;
if (N->getOpcode() != ISD::TargetGlobalAddress)
return TM.getCodeModel() == CodeModel::Small;
Optional<ConstantRange> CR =
cast<GlobalAddressSDNode>(N)->getGlobal()->getAbsoluteSymbolRange();
if (!CR)
return TM.getCodeModel() == CodeModel::Small;
return CR->getUnsignedMax().ult(1ull << 32);
}
bool X86DAGToDAGISel::selectLEA64_32Addr(SDValue N, SDValue &Base,
SDValue &Scale, SDValue &Index,
SDValue &Disp, SDValue &Segment) {
// Save the debug loc before calling selectLEAAddr, in case it invalidates N.
SDLoc DL(N);
if (!selectLEAAddr(N, Base, Scale, Index, Disp, Segment))
return false;
RegisterSDNode *RN = dyn_cast<RegisterSDNode>(Base);
if (RN && RN->getReg() == 0)
Base = CurDAG->getRegister(0, MVT::i64);
else if (Base.getValueType() == MVT::i32 && !isa<FrameIndexSDNode>(Base)) {
// Base could already be %rip, particularly in the x32 ABI.
SDValue ImplDef = SDValue(CurDAG->getMachineNode(X86::IMPLICIT_DEF, DL,
MVT::i64), 0);
Base = CurDAG->getTargetInsertSubreg(X86::sub_32bit, DL, MVT::i64, ImplDef,
Base);
}
RN = dyn_cast<RegisterSDNode>(Index);
if (RN && RN->getReg() == 0)
Index = CurDAG->getRegister(0, MVT::i64);
else {
assert(Index.getValueType() == MVT::i32 &&
"Expect to be extending 32-bit registers for use in LEA");
SDValue ImplDef = SDValue(CurDAG->getMachineNode(X86::IMPLICIT_DEF, DL,
MVT::i64), 0);
Index = CurDAG->getTargetInsertSubreg(X86::sub_32bit, DL, MVT::i64, ImplDef,
Index);
}
return true;
}
/// Calls SelectAddr and determines if the maximal addressing
/// mode it matches can be cost effectively emitted as an LEA instruction.
bool X86DAGToDAGISel::selectLEAAddr(SDValue N,
SDValue &Base, SDValue &Scale,
SDValue &Index, SDValue &Disp,
SDValue &Segment) {
X86ISelAddressMode AM;
// Save the DL and VT before calling matchAddress, it can invalidate N.
SDLoc DL(N);
MVT VT = N.getSimpleValueType();
// Set AM.Segment to prevent MatchAddress from using one. LEA doesn't support
// segments.
SDValue Copy = AM.Segment;
SDValue T = CurDAG->getRegister(0, MVT::i32);
AM.Segment = T;
if (matchAddress(N, AM))
return false;
assert (T == AM.Segment);
AM.Segment = Copy;
unsigned Complexity = 0;
if (AM.BaseType == X86ISelAddressMode::RegBase && AM.Base_Reg.getNode())
Complexity = 1;
else if (AM.BaseType == X86ISelAddressMode::FrameIndexBase)
Complexity = 4;
if (AM.IndexReg.getNode())
Complexity++;
// Don't match just leal(,%reg,2). It's cheaper to do addl %reg, %reg, or with
// a simple shift.
if (AM.Scale > 1)
Complexity++;
// FIXME: We are artificially lowering the criteria to turn ADD %reg, $GA
// to a LEA. This is determined with some experimentation but is by no means
// optimal (especially for code size consideration). LEA is nice because of
// its three-address nature. Tweak the cost function again when we can run
// convertToThreeAddress() at register allocation time.
if (AM.hasSymbolicDisplacement()) {
// For X86-64, always use LEA to materialize RIP-relative addresses.
if (Subtarget->is64Bit())
Complexity = 4;
else
Complexity += 2;
}
// Heuristic: try harder to form an LEA from ADD if the operands set flags.
// Unlike ADD, LEA does not affect flags, so we will be less likely to require
// duplicating flag-producing instructions later in the pipeline.
if (N.getOpcode() == ISD::ADD) {
auto isMathWithFlags = [](SDValue V) {
switch (V.getOpcode()) {
case X86ISD::ADD:
case X86ISD::SUB:
case X86ISD::ADC:
case X86ISD::SBB:
/* TODO: These opcodes can be added safely, but we may want to justify
their inclusion for different reasons (better for reg-alloc).
case X86ISD::SMUL:
case X86ISD::UMUL:
case X86ISD::OR:
case X86ISD::XOR:
case X86ISD::AND:
*/
// Value 1 is the flag output of the node - verify it's not dead.
return !SDValue(V.getNode(), 1).use_empty();
default:
return false;
}
};
// TODO: This could be an 'or' rather than 'and' to make the transform more
// likely to happen. We might want to factor in whether there's a
// load folding opportunity for the math op that disappears with LEA.
if (isMathWithFlags(N.getOperand(0)) && isMathWithFlags(N.getOperand(1)))
Complexity++;
}
if (AM.Disp)
Complexity++;
// If it isn't worth using an LEA, reject it.
if (Complexity <= 2)
return false;
getAddressOperands(AM, DL, VT, Base, Scale, Index, Disp, Segment);
return true;
}
/// This is only run on TargetGlobalTLSAddress nodes.
bool X86DAGToDAGISel::selectTLSADDRAddr(SDValue N, SDValue &Base,
SDValue &Scale, SDValue &Index,
SDValue &Disp, SDValue &Segment) {
assert(N.getOpcode() == ISD::TargetGlobalTLSAddress);
const GlobalAddressSDNode *GA = cast<GlobalAddressSDNode>(N);
X86ISelAddressMode AM;
AM.GV = GA->getGlobal();
AM.Disp += GA->getOffset();
AM.SymbolFlags = GA->getTargetFlags();
MVT VT = N.getSimpleValueType();
if (VT == MVT::i32) {
AM.Scale = 1;
AM.IndexReg = CurDAG->getRegister(X86::EBX, MVT::i32);
}
getAddressOperands(AM, SDLoc(N), VT, Base, Scale, Index, Disp, Segment);
return true;
}
bool X86DAGToDAGISel::selectRelocImm(SDValue N, SDValue &Op) {
if (auto *CN = dyn_cast<ConstantSDNode>(N)) {
Op = CurDAG->getTargetConstant(CN->getAPIntValue(), SDLoc(CN),
N.getValueType());
return true;
}
// Keep track of the original value type and whether this value was
// truncated. If we see a truncation from pointer type to VT that truncates
// bits that are known to be zero, we can use a narrow reference.
EVT VT = N.getValueType();
bool WasTruncated = false;
if (N.getOpcode() == ISD::TRUNCATE) {
WasTruncated = true;
N = N.getOperand(0);
}
if (N.getOpcode() != X86ISD::Wrapper)
return false;
// We can only use non-GlobalValues as immediates if they were not truncated,
// as we do not have any range information. If we have a GlobalValue and the
// address was not truncated, we can select it as an operand directly.
unsigned Opc = N.getOperand(0)->getOpcode();
if (Opc != ISD::TargetGlobalAddress || !WasTruncated) {
Op = N.getOperand(0);
// We can only select the operand directly if we didn't have to look past a
// truncate.
return !WasTruncated;
}
// Check that the global's range fits into VT.
auto *GA = cast<GlobalAddressSDNode>(N.getOperand(0));
Optional<ConstantRange> CR = GA->getGlobal()->getAbsoluteSymbolRange();
if (!CR || CR->getUnsignedMax().uge(1ull << VT.getSizeInBits()))
return false;
// Okay, we can use a narrow reference.
Op = CurDAG->getTargetGlobalAddress(GA->getGlobal(), SDLoc(N), VT,
GA->getOffset(), GA->getTargetFlags());
return true;
}
bool X86DAGToDAGISel::tryFoldLoad(SDNode *Root, SDNode *P, SDValue N,
SDValue &Base, SDValue &Scale,
SDValue &Index, SDValue &Disp,
SDValue &Segment) {
if (!ISD::isNON_EXTLoad(N.getNode()) ||
!IsProfitableToFold(N, P, Root) ||
!IsLegalToFold(N, P, Root, OptLevel))
return false;
return selectAddr(N.getNode(),
N.getOperand(1), Base, Scale, Index, Disp, Segment);
}
/// Return an SDNode that returns the value of the global base register.
/// Output instructions required to initialize the global base register,
/// if necessary.
SDNode *X86DAGToDAGISel::getGlobalBaseReg() {
unsigned GlobalBaseReg = getInstrInfo()->getGlobalBaseReg(MF);
auto &DL = MF->getDataLayout();
return CurDAG->getRegister(GlobalBaseReg, TLI->getPointerTy(DL)).getNode();
}
bool X86DAGToDAGISel::isSExtAbsoluteSymbolRef(unsigned Width, SDNode *N) const {
if (N->getOpcode() == ISD::TRUNCATE)
N = N->getOperand(0).getNode();
if (N->getOpcode() != X86ISD::Wrapper)
return false;
auto *GA = dyn_cast<GlobalAddressSDNode>(N->getOperand(0));
if (!GA)
return false;
Optional<ConstantRange> CR = GA->getGlobal()->getAbsoluteSymbolRange();
return CR && CR->getSignedMin().sge(-1ull << Width) &&
CR->getSignedMax().slt(1ull << Width);
}
static X86::CondCode getCondFromNode(SDNode *N) {
assert(N->isMachineOpcode() && "Unexpected node");
X86::CondCode CC = X86::COND_INVALID;
unsigned Opc = N->getMachineOpcode();
if (Opc == X86::JCC_1)
CC = static_cast<X86::CondCode>(N->getConstantOperandVal(1));
else if (Opc == X86::SETCCr)
CC = static_cast<X86::CondCode>(N->getConstantOperandVal(0));
else if (Opc == X86::SETCCm)
CC = static_cast<X86::CondCode>(N->getConstantOperandVal(5));
else if (Opc == X86::CMOV16rr || Opc == X86::CMOV32rr ||
Opc == X86::CMOV64rr)
CC = static_cast<X86::CondCode>(N->getConstantOperandVal(2));
else if (Opc == X86::CMOV16rm || Opc == X86::CMOV32rm ||
Opc == X86::CMOV64rm)
CC = static_cast<X86::CondCode>(N->getConstantOperandVal(6));
return CC;
}
/// Test whether the given X86ISD::CMP node has any users that use a flag
/// other than ZF.
bool X86DAGToDAGISel::onlyUsesZeroFlag(SDValue Flags) const {
// Examine each user of the node.
for (SDNode::use_iterator UI = Flags->use_begin(), UE = Flags->use_end();
UI != UE; ++UI) {
// Only check things that use the flags.
if (UI.getUse().getResNo() != Flags.getResNo())
continue;
// Only examine CopyToReg uses that copy to EFLAGS.
if (UI->getOpcode() != ISD::CopyToReg ||
cast<RegisterSDNode>(UI->getOperand(1))->getReg() != X86::EFLAGS)
return false;
// Examine each user of the CopyToReg use.
for (SDNode::use_iterator FlagUI = UI->use_begin(),
FlagUE = UI->use_end(); FlagUI != FlagUE; ++FlagUI) {
// Only examine the Flag result.
if (FlagUI.getUse().getResNo() != 1) continue;
// Anything unusual: assume conservatively.
if (!FlagUI->isMachineOpcode()) return false;
// Examine the condition code of the user.
X86::CondCode CC = getCondFromNode(*FlagUI);
switch (CC) {
// Comparisons which only use the zero flag.
case X86::COND_E: case X86::COND_NE:
continue;
// Anything else: assume conservatively.
default:
return false;
}
}
}
return true;
}
/// Test whether the given X86ISD::CMP node has any uses which require the SF
/// flag to be accurate.
bool X86DAGToDAGISel::hasNoSignFlagUses(SDValue Flags) const {
// Examine each user of the node.
for (SDNode::use_iterator UI = Flags->use_begin(), UE = Flags->use_end();
UI != UE; ++UI) {
// Only check things that use the flags.
if (UI.getUse().getResNo() != Flags.getResNo())
continue;
// Only examine CopyToReg uses that copy to EFLAGS.
if (UI->getOpcode() != ISD::CopyToReg ||
cast<RegisterSDNode>(UI->getOperand(1))->getReg() != X86::EFLAGS)
return false;
// Examine each user of the CopyToReg use.
for (SDNode::use_iterator FlagUI = UI->use_begin(),
FlagUE = UI->use_end(); FlagUI != FlagUE; ++FlagUI) {
// Only examine the Flag result.
if (FlagUI.getUse().getResNo() != 1) continue;
// Anything unusual: assume conservatively.
if (!FlagUI->isMachineOpcode()) return false;
// Examine the condition code of the user.
X86::CondCode CC = getCondFromNode(*FlagUI);
switch (CC) {
// Comparisons which don't examine the SF flag.
case X86::COND_A: case X86::COND_AE:
case X86::COND_B: case X86::COND_BE:
case X86::COND_E: case X86::COND_NE:
case X86::COND_O: case X86::COND_NO:
case X86::COND_P: case X86::COND_NP:
continue;
// Anything else: assume conservatively.
default:
return false;
}
}
}
return true;
}
static bool mayUseCarryFlag(X86::CondCode CC) {
switch (CC) {
// Comparisons which don't examine the CF flag.
case X86::COND_O: case X86::COND_NO:
case X86::COND_E: case X86::COND_NE:
case X86::COND_S: case X86::COND_NS:
case X86::COND_P: case X86::COND_NP:
case X86::COND_L: case X86::COND_GE:
case X86::COND_G: case X86::COND_LE:
return false;
// Anything else: assume conservatively.
default:
return true;
}
}
/// Test whether the given node which sets flags has any uses which require the
/// CF flag to be accurate.
bool X86DAGToDAGISel::hasNoCarryFlagUses(SDValue Flags) const {
// Examine each user of the node.
for (SDNode::use_iterator UI = Flags->use_begin(), UE = Flags->use_end();
UI != UE; ++UI) {
// Only check things that use the flags.
if (UI.getUse().getResNo() != Flags.getResNo())
continue;
unsigned UIOpc = UI->getOpcode();
if (UIOpc == ISD::CopyToReg) {
// Only examine CopyToReg uses that copy to EFLAGS.
if (cast<RegisterSDNode>(UI->getOperand(1))->getReg() != X86::EFLAGS)
return false;
// Examine each user of the CopyToReg use.
for (SDNode::use_iterator FlagUI = UI->use_begin(), FlagUE = UI->use_end();
FlagUI != FlagUE; ++FlagUI) {
// Only examine the Flag result.
if (FlagUI.getUse().getResNo() != 1)
continue;
// Anything unusual: assume conservatively.
if (!FlagUI->isMachineOpcode())
return false;
// Examine the condition code of the user.
X86::CondCode CC = getCondFromNode(*FlagUI);
if (mayUseCarryFlag(CC))
return false;
}
// This CopyToReg is ok. Move on to the next user.
continue;
}
// This might be an unselected node. So look for the pre-isel opcodes that
// use flags.
unsigned CCOpNo;
switch (UIOpc) {
default:
// Something unusual. Be conservative.
return false;
case X86ISD::SETCC: CCOpNo = 0; break;
case X86ISD::SETCC_CARRY: CCOpNo = 0; break;
case X86ISD::CMOV: CCOpNo = 2; break;
case X86ISD::BRCOND: CCOpNo = 2; break;
}
X86::CondCode CC = (X86::CondCode)UI->getConstantOperandVal(CCOpNo);
if (mayUseCarryFlag(CC))
return false;
}
return true;
}
/// Check whether or not the chain ending in StoreNode is suitable for doing
/// the {load; op; store} to modify transformation.
static bool isFusableLoadOpStorePattern(StoreSDNode *StoreNode,
SDValue StoredVal, SelectionDAG *CurDAG,
unsigned LoadOpNo,
LoadSDNode *&LoadNode,
SDValue &InputChain) {
// Is the stored value result 0 of the operation?
if (StoredVal.getResNo() != 0) return false;
// Are there other uses of the operation other than the store?
if (!StoredVal.getNode()->hasNUsesOfValue(1, 0)) return false;
// Is the store non-extending and non-indexed?
if (!ISD::isNormalStore(StoreNode) || StoreNode->isNonTemporal())
return false;
SDValue Load = StoredVal->getOperand(LoadOpNo);
// Is the stored value a non-extending and non-indexed load?
if (!ISD::isNormalLoad(Load.getNode())) return false;
// Return LoadNode by reference.
LoadNode = cast<LoadSDNode>(Load);
// Is store the only read of the loaded value?
if (!Load.hasOneUse())
return false;
// Is the address of the store the same as the load?
if (LoadNode->getBasePtr() != StoreNode->getBasePtr() ||
LoadNode->getOffset() != StoreNode->getOffset())
return false;
bool FoundLoad = false;
SmallVector<SDValue, 4> ChainOps;
SmallVector<const SDNode *, 4> LoopWorklist;
SmallPtrSet<const SDNode *, 16> Visited;
const unsigned int Max = 1024;
// Visualization of Load-Op-Store fusion:
// -------------------------
// Legend:
// *-lines = Chain operand dependencies.
// |-lines = Normal operand dependencies.
// Dependencies flow down and right. n-suffix references multiple nodes.
//
// C Xn C
// * * *
// * * *
// Xn A-LD Yn TF Yn
// * * \ | * |
// * * \ | * |
// * * \ | => A--LD_OP_ST
// * * \| \
// TF OP \
// * | \ Zn
// * | \
// A-ST Zn
//
// This merge induced dependences from: #1: Xn -> LD, OP, Zn
// #2: Yn -> LD
// #3: ST -> Zn
// Ensure the transform is safe by checking for the dual
// dependencies to make sure we do not induce a loop.
// As LD is a predecessor to both OP and ST we can do this by checking:
// a). if LD is a predecessor to a member of Xn or Yn.
// b). if a Zn is a predecessor to ST.
// However, (b) can only occur through being a chain predecessor to
// ST, which is the same as Zn being a member or predecessor of Xn,
// which is a subset of LD being a predecessor of Xn. So it's
// subsumed by check (a).
SDValue Chain = StoreNode->getChain();
// Gather X elements in ChainOps.
if (Chain == Load.getValue(1)) {
FoundLoad = true;
ChainOps.push_back(Load.getOperand(0));
} else if (Chain.getOpcode() == ISD::TokenFactor) {
for (unsigned i = 0, e = Chain.getNumOperands(); i != e; ++i) {
SDValue Op = Chain.getOperand(i);
if (Op == Load.getValue(1)) {
FoundLoad = true;
// Drop Load, but keep its chain. No cycle check necessary.
ChainOps.push_back(Load.getOperand(0));
continue;
}
LoopWorklist.push_back(Op.getNode());
ChainOps.push_back(Op);
}
}
if (!FoundLoad)
return false;
// Worklist is currently Xn. Add Yn to worklist.
for (SDValue Op : StoredVal->ops())
if (Op.getNode() != LoadNode)
LoopWorklist.push_back(Op.getNode());
// Check (a) if Load is a predecessor to Xn + Yn
if (SDNode::hasPredecessorHelper(Load.getNode(), Visited, LoopWorklist, Max,
true))
return false;
InputChain =
CurDAG->getNode(ISD::TokenFactor, SDLoc(Chain), MVT::Other, ChainOps);
return true;
}
// Change a chain of {load; op; store} of the same value into a simple op
// through memory of that value, if the uses of the modified value and its
// address are suitable.
//
// The tablegen pattern memory operand pattern is currently not able to match
// the case where the EFLAGS on the original operation are used.
//
// To move this to tablegen, we'll need to improve tablegen to allow flags to
// be transferred from a node in the pattern to the result node, probably with
// a new keyword. For example, we have this
// def DEC64m : RI<0xFF, MRM1m, (outs), (ins i64mem:$dst), "dec{q}\t$dst",
// [(store (add (loadi64 addr:$dst), -1), addr:$dst),
// (implicit EFLAGS)]>;
// but maybe need something like this
// def DEC64m : RI<0xFF, MRM1m, (outs), (ins i64mem:$dst), "dec{q}\t$dst",
// [(store (add (loadi64 addr:$dst), -1), addr:$dst),
// (transferrable EFLAGS)]>;
//
// Until then, we manually fold these and instruction select the operation
// here.
bool X86DAGToDAGISel::foldLoadStoreIntoMemOperand(SDNode *Node) {
StoreSDNode *StoreNode = cast<StoreSDNode>(Node);
SDValue StoredVal = StoreNode->getOperand(1);
unsigned Opc = StoredVal->getOpcode();
// Before we try to select anything, make sure this is memory operand size
// and opcode we can handle. Note that this must match the code below that
// actually lowers the opcodes.
EVT MemVT = StoreNode->getMemoryVT();
if (MemVT != MVT::i64 && MemVT != MVT::i32 && MemVT != MVT::i16 &&
MemVT != MVT::i8)
return false;
bool IsCommutable = false;
bool IsNegate = false;
switch (Opc) {
default:
return false;
case X86ISD::SUB:
IsNegate = isNullConstant(StoredVal.getOperand(0));
break;
case X86ISD::SBB:
break;
case X86ISD::ADD:
case X86ISD::ADC:
case X86ISD::AND:
case X86ISD::OR:
case X86ISD::XOR:
IsCommutable = true;
break;
}
unsigned LoadOpNo = IsNegate ? 1 : 0;
LoadSDNode *LoadNode = nullptr;
SDValue InputChain;
if (!isFusableLoadOpStorePattern(StoreNode, StoredVal, CurDAG, LoadOpNo,
LoadNode, InputChain)) {
if (!IsCommutable)
return false;
// This operation is commutable, try the other operand.
LoadOpNo = 1;
if (!isFusableLoadOpStorePattern(StoreNode, StoredVal, CurDAG, LoadOpNo,
LoadNode, InputChain))
return false;
}
SDValue Base, Scale, Index, Disp, Segment;
if (!selectAddr(LoadNode, LoadNode->getBasePtr(), Base, Scale, Index, Disp,
Segment))
return false;
auto SelectOpcode = [&](unsigned Opc64, unsigned Opc32, unsigned Opc16,
unsigned Opc8) {
switch (MemVT.getSimpleVT().SimpleTy) {
case MVT::i64:
return Opc64;
case MVT::i32:
return Opc32;
case MVT::i16:
return Opc16;
case MVT::i8:
return Opc8;
default:
llvm_unreachable("Invalid size!");
}
};
MachineSDNode *Result;
switch (Opc) {
case X86ISD::SUB:
// Handle negate.
if (IsNegate) {
unsigned NewOpc = SelectOpcode(X86::NEG64m, X86::NEG32m, X86::NEG16m,
X86::NEG8m);
const SDValue Ops[] = {Base, Scale, Index, Disp, Segment, InputChain};
Result = CurDAG->getMachineNode(NewOpc, SDLoc(Node), MVT::i32,
MVT::Other, Ops);
break;
}
LLVM_FALLTHROUGH;
case X86ISD::ADD:
// Try to match inc/dec.
if (!Subtarget->slowIncDec() || OptForSize) {
bool IsOne = isOneConstant(StoredVal.getOperand(1));
bool IsNegOne = isAllOnesConstant(StoredVal.getOperand(1));
// ADD/SUB with 1/-1 and carry flag isn't used can use inc/dec.
if ((IsOne || IsNegOne) && hasNoCarryFlagUses(StoredVal.getValue(1))) {
unsigned NewOpc =
((Opc == X86ISD::ADD) == IsOne)
? SelectOpcode(X86::INC64m, X86::INC32m, X86::INC16m, X86::INC8m)
: SelectOpcode(X86::DEC64m, X86::DEC32m, X86::DEC16m, X86::DEC8m);
const SDValue Ops[] = {Base, Scale, Index, Disp, Segment, InputChain};
Result = CurDAG->getMachineNode(NewOpc, SDLoc(Node), MVT::i32,
MVT::Other, Ops);
break;
}
}
LLVM_FALLTHROUGH;
case X86ISD::ADC:
case X86ISD::SBB:
case X86ISD::AND:
case X86ISD::OR:
case X86ISD::XOR: {
auto SelectRegOpcode = [SelectOpcode](unsigned Opc) {
switch (Opc) {
case X86ISD::ADD:
return SelectOpcode(X86::ADD64mr, X86::ADD32mr, X86::ADD16mr,
X86::ADD8mr);
case X86ISD::ADC:
return SelectOpcode(X86::ADC64mr, X86::ADC32mr, X86::ADC16mr,
X86::ADC8mr);
case X86ISD::SUB:
return SelectOpcode(X86::SUB64mr, X86::SUB32mr, X86::SUB16mr,
X86::SUB8mr);
case X86ISD::SBB:
return SelectOpcode(X86::SBB64mr, X86::SBB32mr, X86::SBB16mr,
X86::SBB8mr);
case X86ISD::AND:
return SelectOpcode(X86::AND64mr, X86::AND32mr, X86::AND16mr,
X86::AND8mr);
case X86ISD::OR:
return SelectOpcode(X86::OR64mr, X86::OR32mr, X86::OR16mr, X86::OR8mr);
case X86ISD::XOR:
return SelectOpcode(X86::XOR64mr, X86::XOR32mr, X86::XOR16mr,
X86::XOR8mr);
default:
llvm_unreachable("Invalid opcode!");
}
};
auto SelectImm8Opcode = [SelectOpcode](unsigned Opc) {
switch (Opc) {
case X86ISD::ADD:
return SelectOpcode(X86::ADD64mi8, X86::ADD32mi8, X86::ADD16mi8, 0);
case X86ISD::ADC:
return SelectOpcode(X86::ADC64mi8, X86::ADC32mi8, X86::ADC16mi8, 0);
case X86ISD::SUB:
return SelectOpcode(X86::SUB64mi8, X86::SUB32mi8, X86::SUB16mi8, 0);
case X86ISD::SBB:
return SelectOpcode(X86::SBB64mi8, X86::SBB32mi8, X86::SBB16mi8, 0);
case X86ISD::AND:
return SelectOpcode(X86::AND64mi8, X86::AND32mi8, X86::AND16mi8, 0);
case X86ISD::OR:
return SelectOpcode(X86::OR64mi8, X86::OR32mi8, X86::OR16mi8, 0);
case X86ISD::XOR:
return SelectOpcode(X86::XOR64mi8, X86::XOR32mi8, X86::XOR16mi8, 0);
default:
llvm_unreachable("Invalid opcode!");
}
};
auto SelectImmOpcode = [SelectOpcode](unsigned Opc) {
switch (Opc) {
case X86ISD::ADD:
return SelectOpcode(X86::ADD64mi32, X86::ADD32mi, X86::ADD16mi,
X86::ADD8mi);
case X86ISD::ADC:
return SelectOpcode(X86::ADC64mi32, X86::ADC32mi, X86::ADC16mi,
X86::ADC8mi);
case X86ISD::SUB:
return SelectOpcode(X86::SUB64mi32, X86::SUB32mi, X86::SUB16mi,
X86::SUB8mi);
case X86ISD::SBB:
return SelectOpcode(X86::SBB64mi32, X86::SBB32mi, X86::SBB16mi,
X86::SBB8mi);
case X86ISD::AND:
return SelectOpcode(X86::AND64mi32, X86::AND32mi, X86::AND16mi,
X86::AND8mi);
case X86ISD::OR:
return SelectOpcode(X86::OR64mi32, X86::OR32mi, X86::OR16mi,
X86::OR8mi);
case X86ISD::XOR:
return SelectOpcode(X86::XOR64mi32, X86::XOR32mi, X86::XOR16mi,
X86::XOR8mi);
default:
llvm_unreachable("Invalid opcode!");
}
};
unsigned NewOpc = SelectRegOpcode(Opc);
SDValue Operand = StoredVal->getOperand(1-LoadOpNo);
// See if the operand is a constant that we can fold into an immediate
// operand.
if (auto *OperandC = dyn_cast<ConstantSDNode>(Operand)) {
int64_t OperandV = OperandC->getSExtValue();
// Check if we can shrink the operand enough to fit in an immediate (or
// fit into a smaller immediate) by negating it and switching the
// operation.
if ((Opc == X86ISD::ADD || Opc == X86ISD::SUB) &&
((MemVT != MVT::i8 && !isInt<8>(OperandV) && isInt<8>(-OperandV)) ||
(MemVT == MVT::i64 && !isInt<32>(OperandV) &&
isInt<32>(-OperandV))) &&
hasNoCarryFlagUses(StoredVal.getValue(1))) {
OperandV = -OperandV;
Opc = Opc == X86ISD::ADD ? X86ISD::SUB : X86ISD::ADD;
}
// First try to fit this into an Imm8 operand. If it doesn't fit, then try
// the larger immediate operand.
if (MemVT != MVT::i8 && isInt<8>(OperandV)) {
Operand = CurDAG->getTargetConstant(OperandV, SDLoc(Node), MemVT);
NewOpc = SelectImm8Opcode(Opc);
} else if (MemVT != MVT::i64 || isInt<32>(OperandV)) {
Operand = CurDAG->getTargetConstant(OperandV, SDLoc(Node), MemVT);
NewOpc = SelectImmOpcode(Opc);
}
}
if (Opc == X86ISD::ADC || Opc == X86ISD::SBB) {
SDValue CopyTo =
CurDAG->getCopyToReg(InputChain, SDLoc(Node), X86::EFLAGS,
StoredVal.getOperand(2), SDValue());
const SDValue Ops[] = {Base, Scale, Index, Disp,
Segment, Operand, CopyTo, CopyTo.getValue(1)};
Result = CurDAG->getMachineNode(NewOpc, SDLoc(Node), MVT::i32, MVT::Other,
Ops);
} else {
const SDValue Ops[] = {Base, Scale, Index, Disp,
Segment, Operand, InputChain};
Result = CurDAG->getMachineNode(NewOpc, SDLoc(Node), MVT::i32, MVT::Other,
Ops);
}
break;
}
default:
llvm_unreachable("Invalid opcode!");
}
MachineMemOperand *MemOps[] = {StoreNode->getMemOperand(),
LoadNode->getMemOperand()};
CurDAG->setNodeMemRefs(Result, MemOps);
// Update Load Chain uses as well.
ReplaceUses(SDValue(LoadNode, 1), SDValue(Result, 1));
ReplaceUses(SDValue(StoreNode, 0), SDValue(Result, 1));
ReplaceUses(SDValue(StoredVal.getNode(), 1), SDValue(Result, 0));
CurDAG->RemoveDeadNode(Node);
return true;
}
// See if this is an X & Mask that we can match to BEXTR/BZHI.
// Where Mask is one of the following patterns:
// a) x & (1 << nbits) - 1
// b) x & ~(-1 << nbits)
// c) x & (-1 >> (32 - y))
// d) x << (32 - y) >> (32 - y)
bool X86DAGToDAGISel::matchBitExtract(SDNode *Node) {
assert(
(Node->getOpcode() == ISD::AND || Node->getOpcode() == ISD::SRL) &&
"Should be either an and-mask, or right-shift after clearing high bits.");
// BEXTR is BMI instruction, BZHI is BMI2 instruction. We need at least one.
if (!Subtarget->hasBMI() && !Subtarget->hasBMI2())
return false;
MVT NVT = Node->getSimpleValueType(0);
// Only supported for 32 and 64 bits.
if (NVT != MVT::i32 && NVT != MVT::i64)
return false;
SDValue NBits;
// If we have BMI2's BZHI, we are ok with muti-use patterns.
// Else, if we only have BMI1's BEXTR, we require one-use.
const bool CanHaveExtraUses = Subtarget->hasBMI2();
auto checkUses = [CanHaveExtraUses](SDValue Op, unsigned NUses) {
return CanHaveExtraUses ||
Op.getNode()->hasNUsesOfValue(NUses, Op.getResNo());
};
auto checkOneUse = [checkUses](SDValue Op) { return checkUses(Op, 1); };
auto checkTwoUse = [checkUses](SDValue Op) { return checkUses(Op, 2); };
auto peekThroughOneUseTruncation = [checkOneUse](SDValue V) {
if (V->getOpcode() == ISD::TRUNCATE && checkOneUse(V)) {
assert(V.getSimpleValueType() == MVT::i32 &&
V.getOperand(0).getSimpleValueType() == MVT::i64 &&
"Expected i64 -> i32 truncation");
V = V.getOperand(0);
}
return V;
};
// a) x & ((1 << nbits) + (-1))
auto matchPatternA = [checkOneUse, peekThroughOneUseTruncation,
&NBits](SDValue Mask) -> bool {
// Match `add`. Must only have one use!
if (Mask->getOpcode() != ISD::ADD || !checkOneUse(Mask))
return false;
// We should be adding all-ones constant (i.e. subtracting one.)
if (!isAllOnesConstant(Mask->getOperand(1)))
return false;
// Match `1 << nbits`. Might be truncated. Must only have one use!
SDValue M0 = peekThroughOneUseTruncation(Mask->getOperand(0));
if (M0->getOpcode() != ISD::SHL || !checkOneUse(M0))
return false;
if (!isOneConstant(M0->getOperand(0)))
return false;
NBits = M0->getOperand(1);
return true;
};
auto isAllOnes = [this, peekThroughOneUseTruncation, NVT](SDValue V) {
V = peekThroughOneUseTruncation(V);
return CurDAG->MaskedValueIsAllOnes(
V, APInt::getLowBitsSet(V.getSimpleValueType().getSizeInBits(),
NVT.getSizeInBits()));
};
// b) x & ~(-1 << nbits)
auto matchPatternB = [checkOneUse, isAllOnes, peekThroughOneUseTruncation,
&NBits](SDValue Mask) -> bool {
// Match `~()`. Must only have one use!
if (Mask.getOpcode() != ISD::XOR || !checkOneUse(Mask))
return false;
// The -1 only has to be all-ones for the final Node's NVT.
if (!isAllOnes(Mask->getOperand(1)))
return false;
// Match `-1 << nbits`. Might be truncated. Must only have one use!
SDValue M0 = peekThroughOneUseTruncation(Mask->getOperand(0));
if (M0->getOpcode() != ISD::SHL || !checkOneUse(M0))
return false;
// The -1 only has to be all-ones for the final Node's NVT.
if (!isAllOnes(M0->getOperand(0)))
return false;
NBits = M0->getOperand(1);
return true;
};
// Match potentially-truncated (bitwidth - y)
auto matchShiftAmt = [checkOneUse, &NBits](SDValue ShiftAmt,
unsigned Bitwidth) {
// Skip over a truncate of the shift amount.
if (ShiftAmt.getOpcode() == ISD::TRUNCATE) {
ShiftAmt = ShiftAmt.getOperand(0);
// The trunc should have been the only user of the real shift amount.
if (!checkOneUse(ShiftAmt))
return false;
}
// Match the shift amount as: (bitwidth - y). It should go away, too.
if (ShiftAmt.getOpcode() != ISD::SUB)
return false;
auto V0 = dyn_cast<ConstantSDNode>(ShiftAmt.getOperand(0));
if (!V0 || V0->getZExtValue() != Bitwidth)
return false;
NBits = ShiftAmt.getOperand(1);
return true;
};
// c) x & (-1 >> (32 - y))
auto matchPatternC = [checkOneUse, peekThroughOneUseTruncation,
matchShiftAmt](SDValue Mask) -> bool {
// The mask itself may be truncated.
Mask = peekThroughOneUseTruncation(Mask);
unsigned Bitwidth = Mask.getSimpleValueType().getSizeInBits();
// Match `l>>`. Must only have one use!
if (Mask.getOpcode() != ISD::SRL || !checkOneUse(Mask))
return false;
// We should be shifting truly all-ones constant.
if (!isAllOnesConstant(Mask.getOperand(0)))
return false;
SDValue M1 = Mask.getOperand(1);
// The shift amount should not be used externally.
if (!checkOneUse(M1))
return false;
return matchShiftAmt(M1, Bitwidth);
};
SDValue X;
// d) x << (32 - y) >> (32 - y)
auto matchPatternD = [checkOneUse, checkTwoUse, matchShiftAmt,
&X](SDNode *Node) -> bool {
if (Node->getOpcode() != ISD::SRL)
return false;
SDValue N0 = Node->getOperand(0);
if (N0->getOpcode() != ISD::SHL || !checkOneUse(N0))
return false;
unsigned Bitwidth = N0.getSimpleValueType().getSizeInBits();
SDValue N1 = Node->getOperand(1);
SDValue N01 = N0->getOperand(1);
// Both of the shifts must be by the exact same value.
// There should not be any uses of the shift amount outside of the pattern.
if (N1 != N01 || !checkTwoUse(N1))
return false;
if (!matchShiftAmt(N1, Bitwidth))
return false;
X = N0->getOperand(0);
return true;
};
auto matchLowBitMask = [matchPatternA, matchPatternB,
matchPatternC](SDValue Mask) -> bool {
return matchPatternA(Mask) || matchPatternB(Mask) || matchPatternC(Mask);
};
if (Node->getOpcode() == ISD::AND) {
X = Node->getOperand(0);
SDValue Mask = Node->getOperand(1);
if (matchLowBitMask(Mask)) {
// Great.
} else {
std::swap(X, Mask);
if (!matchLowBitMask(Mask))
return false;
}
} else if (!matchPatternD(Node))
return false;
SDLoc DL(Node);
// Truncate the shift amount.
NBits = CurDAG->getNode(ISD::TRUNCATE, DL, MVT::i8, NBits);
insertDAGNode(*CurDAG, SDValue(Node, 0), NBits);
// Insert 8-bit NBits into lowest 8 bits of 32-bit register.
// All the other bits are undefined, we do not care about them.
SDValue ImplDef = SDValue(
CurDAG->getMachineNode(TargetOpcode::IMPLICIT_DEF, DL, MVT::i32), 0);
insertDAGNode(*CurDAG, SDValue(Node, 0), ImplDef);
NBits = CurDAG->getTargetInsertSubreg(X86::sub_8bit, DL, MVT::i32, ImplDef,
NBits);
insertDAGNode(*CurDAG, SDValue(Node, 0), NBits);
if (Subtarget->hasBMI2()) {
// Great, just emit the the BZHI..
if (NVT != MVT::i32) {
// But have to place the bit count into the wide-enough register first.
NBits = CurDAG->getNode(ISD::ANY_EXTEND, DL, NVT, NBits);
insertDAGNode(*CurDAG, SDValue(Node, 0), NBits);
}
SDValue Extract = CurDAG->getNode(X86ISD::BZHI, DL, NVT, X, NBits);
ReplaceNode(Node, Extract.getNode());
SelectCode(Extract.getNode());
return true;
}
// Else, if we do *NOT* have BMI2, let's find out if the if the 'X' is
// *logically* shifted (potentially with one-use trunc inbetween),
// and the truncation was the only use of the shift,
// and if so look past one-use truncation.
{
SDValue RealX = peekThroughOneUseTruncation(X);
// FIXME: only if the shift is one-use?
if (RealX != X && RealX.getOpcode() == ISD::SRL)
X = RealX;
}
MVT XVT = X.getSimpleValueType();
// Else, emitting BEXTR requires one more step.
// The 'control' of BEXTR has the pattern of:
// [15...8 bit][ 7...0 bit] location
// [ bit count][ shift] name
// I.e. 0b000000011'00000001 means (x >> 0b1) & 0b11
// Shift NBits left by 8 bits, thus producing 'control'.
// This makes the low 8 bits to be zero.
SDValue C8 = CurDAG->getConstant(8, DL, MVT::i8);
SDValue Control = CurDAG->getNode(ISD::SHL, DL, MVT::i32, NBits, C8);
insertDAGNode(*CurDAG, SDValue(Node, 0), Control);
// If the 'X' is *logically* shifted, we can fold that shift into 'control'.
// FIXME: only if the shift is one-use?
if (X.getOpcode() == ISD::SRL) {
SDValue ShiftAmt = X.getOperand(1);
X = X.getOperand(0);
assert(ShiftAmt.getValueType() == MVT::i8 &&
"Expected shift amount to be i8");
// Now, *zero*-extend the shift amount. The bits 8...15 *must* be zero!
// We could zext to i16 in some form, but we intentionally don't do that.
SDValue OrigShiftAmt = ShiftAmt;
ShiftAmt = CurDAG->getNode(ISD::ZERO_EXTEND, DL, MVT::i32, ShiftAmt);
insertDAGNode(*CurDAG, OrigShiftAmt, ShiftAmt);
// And now 'or' these low 8 bits of shift amount into the 'control'.
Control = CurDAG->getNode(ISD::OR, DL, MVT::i32, Control, ShiftAmt);
insertDAGNode(*CurDAG, SDValue(Node, 0), Control);
}
// But have to place the 'control' into the wide-enough register first.
if (XVT != MVT::i32) {
Control = CurDAG->getNode(ISD::ANY_EXTEND, DL, XVT, Control);
insertDAGNode(*CurDAG, SDValue(Node, 0), Control);
}
// And finally, form the BEXTR itself.
SDValue Extract = CurDAG->getNode(X86ISD::BEXTR, DL, XVT, X, Control);
// The 'X' was originally truncated. Do that now.
if (XVT != NVT) {
insertDAGNode(*CurDAG, SDValue(Node, 0), Extract);
Extract = CurDAG->getNode(ISD::TRUNCATE, DL, NVT, Extract);
}
ReplaceNode(Node, Extract.getNode());
SelectCode(Extract.getNode());
return true;
}
// See if this is an (X >> C1) & C2 that we can match to BEXTR/BEXTRI.
MachineSDNode *X86DAGToDAGISel::matchBEXTRFromAndImm(SDNode *Node) {
MVT NVT = Node->getSimpleValueType(0);
SDLoc dl(Node);
SDValue N0 = Node->getOperand(0);
SDValue N1 = Node->getOperand(1);
// If we have TBM we can use an immediate for the control. If we have BMI
// we should only do this if the BEXTR instruction is implemented well.
// Otherwise moving the control into a register makes this more costly.
// TODO: Maybe load folding, greater than 32-bit masks, or a guarantee of LICM
// hoisting the move immediate would make it worthwhile with a less optimal
// BEXTR?
if (!Subtarget->hasTBM() &&
!(Subtarget->hasBMI() && Subtarget->hasFastBEXTR()))
return nullptr;
// Must have a shift right.
if (N0->getOpcode() != ISD::SRL && N0->getOpcode() != ISD::SRA)
return nullptr;
// Shift can't have additional users.
if (!N0->hasOneUse())
return nullptr;
// Only supported for 32 and 64 bits.
if (NVT != MVT::i32 && NVT != MVT::i64)
return nullptr;
// Shift amount and RHS of and must be constant.
ConstantSDNode *MaskCst = dyn_cast<ConstantSDNode>(N1);
ConstantSDNode *ShiftCst = dyn_cast<ConstantSDNode>(N0->getOperand(1));
if (!MaskCst || !ShiftCst)
return nullptr;
// And RHS must be a mask.
uint64_t Mask = MaskCst->getZExtValue();
if (!isMask_64(Mask))
return nullptr;
uint64_t Shift = ShiftCst->getZExtValue();
uint64_t MaskSize = countPopulation(Mask);
// Don't interfere with something that can be handled by extracting AH.
// TODO: If we are able to fold a load, BEXTR might still be better than AH.
if (Shift == 8 && MaskSize == 8)
return nullptr;
// Make sure we are only using bits that were in the original value, not
// shifted in.
if (Shift + MaskSize > NVT.getSizeInBits())
return nullptr;
SDValue New = CurDAG->getTargetConstant(Shift | (MaskSize << 8), dl, NVT);
unsigned ROpc = NVT == MVT::i64 ? X86::BEXTRI64ri : X86::BEXTRI32ri;
unsigned MOpc = NVT == MVT::i64 ? X86::BEXTRI64mi : X86::BEXTRI32mi;
// BMI requires the immediate to placed in a register.
if (!Subtarget->hasTBM()) {
ROpc = NVT == MVT::i64 ? X86::BEXTR64rr : X86::BEXTR32rr;
MOpc = NVT == MVT::i64 ? X86::BEXTR64rm : X86::BEXTR32rm;
unsigned NewOpc = NVT == MVT::i64 ? X86::MOV32ri64 : X86::MOV32ri;
New = SDValue(CurDAG->getMachineNode(NewOpc, dl, NVT, New), 0);
}
MachineSDNode *NewNode;
SDValue Input = N0->getOperand(0);
SDValue Tmp0, Tmp1, Tmp2, Tmp3, Tmp4;
if (tryFoldLoad(Node, N0.getNode(), Input, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4)) {
SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, New, Input.getOperand(0) };
SDVTList VTs = CurDAG->getVTList(NVT, MVT::i32, MVT::Other);
NewNode = CurDAG->getMachineNode(MOpc, dl, VTs, Ops);
// Update the chain.
ReplaceUses(Input.getValue(1), SDValue(NewNode, 2));
// Record the mem-refs
CurDAG->setNodeMemRefs(NewNode, {cast<LoadSDNode>(Input)->getMemOperand()});
} else {
NewNode = CurDAG->getMachineNode(ROpc, dl, NVT, MVT::i32, Input, New);
}
return NewNode;
}
// Emit a PCMISTR(I/M) instruction.
MachineSDNode *X86DAGToDAGISel::emitPCMPISTR(unsigned ROpc, unsigned MOpc,
bool MayFoldLoad, const SDLoc &dl,
MVT VT, SDNode *Node) {
SDValue N0 = Node->getOperand(0);
SDValue N1 = Node->getOperand(1);
SDValue Imm = Node->getOperand(2);
const ConstantInt *Val = cast<ConstantSDNode>(Imm)->getConstantIntValue();
Imm = CurDAG->getTargetConstant(*Val, SDLoc(Node), Imm.getValueType());
// Try to fold a load. No need to check alignment.
SDValue Tmp0, Tmp1, Tmp2, Tmp3, Tmp4;
if (MayFoldLoad && tryFoldLoad(Node, N1, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4)) {
SDValue Ops[] = { N0, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, Imm,
N1.getOperand(0) };
SDVTList VTs = CurDAG->getVTList(VT, MVT::i32, MVT::Other);
MachineSDNode *CNode = CurDAG->getMachineNode(MOpc, dl, VTs, Ops);
// Update the chain.
ReplaceUses(N1.getValue(1), SDValue(CNode, 2));
// Record the mem-refs
CurDAG->setNodeMemRefs(CNode, {cast<LoadSDNode>(N1)->getMemOperand()});
return CNode;
}
SDValue Ops[] = { N0, N1, Imm };
SDVTList VTs = CurDAG->getVTList(VT, MVT::i32);
MachineSDNode *CNode = CurDAG->getMachineNode(ROpc, dl, VTs, Ops);
return CNode;
}
// Emit a PCMESTR(I/M) instruction. Also return the Glue result in case we need
// to emit a second instruction after this one. This is needed since we have two
// copyToReg nodes glued before this and we need to continue that glue through.
MachineSDNode *X86DAGToDAGISel::emitPCMPESTR(unsigned ROpc, unsigned MOpc,
bool MayFoldLoad, const SDLoc &dl,
MVT VT, SDNode *Node,
SDValue &InFlag) {
SDValue N0 = Node->getOperand(0);
SDValue N2 = Node->getOperand(2);
SDValue Imm = Node->getOperand(4);
const ConstantInt *Val = cast<ConstantSDNode>(Imm)->getConstantIntValue();
Imm = CurDAG->getTargetConstant(*Val, SDLoc(Node), Imm.getValueType());
// Try to fold a load. No need to check alignment.
SDValue Tmp0, Tmp1, Tmp2, Tmp3, Tmp4;
if (MayFoldLoad && tryFoldLoad(Node, N2, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4)) {
SDValue Ops[] = { N0, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, Imm,
N2.getOperand(0), InFlag };
SDVTList VTs = CurDAG->getVTList(VT, MVT::i32, MVT::Other, MVT::Glue);
MachineSDNode *CNode = CurDAG->getMachineNode(MOpc, dl, VTs, Ops);
InFlag = SDValue(CNode, 3);
// Update the chain.
ReplaceUses(N2.getValue(1), SDValue(CNode, 2));
// Record the mem-refs
CurDAG->setNodeMemRefs(CNode, {cast<LoadSDNode>(N2)->getMemOperand()});
return CNode;
}
SDValue Ops[] = { N0, N2, Imm, InFlag };
SDVTList VTs = CurDAG->getVTList(VT, MVT::i32, MVT::Glue);
MachineSDNode *CNode = CurDAG->getMachineNode(ROpc, dl, VTs, Ops);
InFlag = SDValue(CNode, 2);
return CNode;
}
bool X86DAGToDAGISel::tryShiftAmountMod(SDNode *N) {
EVT VT = N->getValueType(0);
// Only handle scalar shifts.
if (VT.isVector())
return false;
// Narrower shifts only mask to 5 bits in hardware.
unsigned Size = VT == MVT::i64 ? 64 : 32;
SDValue OrigShiftAmt = N->getOperand(1);
SDValue ShiftAmt = OrigShiftAmt;
SDLoc DL(N);
// Skip over a truncate of the shift amount.
if (ShiftAmt->getOpcode() == ISD::TRUNCATE)
ShiftAmt = ShiftAmt->getOperand(0);
// This function is called after X86DAGToDAGISel::matchBitExtract(),
// so we are not afraid that we might mess up BZHI/BEXTR pattern.
SDValue NewShiftAmt;
if (ShiftAmt->getOpcode() == ISD::ADD || ShiftAmt->getOpcode() == ISD::SUB) {
SDValue Add0 = ShiftAmt->getOperand(0);
SDValue Add1 = ShiftAmt->getOperand(1);
// If we are shifting by X+/-N where N == 0 mod Size, then just shift by X
// to avoid the ADD/SUB.
if (isa<ConstantSDNode>(Add1) &&
cast<ConstantSDNode>(Add1)->getZExtValue() % Size == 0) {
NewShiftAmt = Add0;
// If we are shifting by N-X where N == 0 mod Size, then just shift by -X to
// generate a NEG instead of a SUB of a constant.
} else if (ShiftAmt->getOpcode() == ISD::SUB &&
isa<ConstantSDNode>(Add0) &&
cast<ConstantSDNode>(Add0)->getZExtValue() != 0 &&
cast<ConstantSDNode>(Add0)->getZExtValue() % Size == 0) {
// Insert a negate op.
// TODO: This isn't guaranteed to replace the sub if there is a logic cone
// that uses it that's not a shift.
EVT SubVT = ShiftAmt.getValueType();
SDValue Zero = CurDAG->getConstant(0, DL, SubVT);
SDValue Neg = CurDAG->getNode(ISD::SUB, DL, SubVT, Zero, Add1);
NewShiftAmt = Neg;
// Insert these operands into a valid topological order so they can
// get selected independently.
insertDAGNode(*CurDAG, OrigShiftAmt, Zero);
insertDAGNode(*CurDAG, OrigShiftAmt, Neg);
} else
return false;
} else
return false;
if (NewShiftAmt.getValueType() != MVT::i8) {
// Need to truncate the shift amount.
NewShiftAmt = CurDAG->getNode(ISD::TRUNCATE, DL, MVT::i8, NewShiftAmt);
// Add to a correct topological ordering.
insertDAGNode(*CurDAG, OrigShiftAmt, NewShiftAmt);
}
// Insert a new mask to keep the shift amount legal. This should be removed
// by isel patterns.
NewShiftAmt = CurDAG->getNode(ISD::AND, DL, MVT::i8, NewShiftAmt,
CurDAG->getConstant(Size - 1, DL, MVT::i8));
// Place in a correct topological ordering.
insertDAGNode(*CurDAG, OrigShiftAmt, NewShiftAmt);
SDNode *UpdatedNode = CurDAG->UpdateNodeOperands(N, N->getOperand(0),
NewShiftAmt);
if (UpdatedNode != N) {
// If we found an existing node, we should replace ourselves with that node
// and wait for it to be selected after its other users.
ReplaceNode(N, UpdatedNode);
return true;
}
// If the original shift amount is now dead, delete it so that we don't run
// it through isel.
if (OrigShiftAmt.getNode()->use_empty())
CurDAG->RemoveDeadNode(OrigShiftAmt.getNode());
// Now that we've optimized the shift amount, defer to normal isel to get
// load folding and legacy vs BMI2 selection without repeating it here.
SelectCode(N);
return true;
}
bool X86DAGToDAGISel::tryShrinkShlLogicImm(SDNode *N) {
MVT NVT = N->getSimpleValueType(0);
unsigned Opcode = N->getOpcode();
SDLoc dl(N);
// For operations of the form (x << C1) op C2, check if we can use a smaller
// encoding for C2 by transforming it into (x op (C2>>C1)) << C1.
SDValue Shift = N->getOperand(0);
SDValue N1 = N->getOperand(1);
ConstantSDNode *Cst = dyn_cast<ConstantSDNode>(N1);
if (!Cst)
return false;
int64_t Val = Cst->getSExtValue();
// If we have an any_extend feeding the AND, look through it to see if there
// is a shift behind it. But only if the AND doesn't use the extended bits.
// FIXME: Generalize this to other ANY_EXTEND than i32 to i64?
bool FoundAnyExtend = false;
if (Shift.getOpcode() == ISD::ANY_EXTEND && Shift.hasOneUse() &&
Shift.getOperand(0).getSimpleValueType() == MVT::i32 &&
isUInt<32>(Val)) {
FoundAnyExtend = true;
Shift = Shift.getOperand(0);
}
if (Shift.getOpcode() != ISD::SHL || !Shift.hasOneUse())
return false;
// i8 is unshrinkable, i16 should be promoted to i32.
if (NVT != MVT::i32 && NVT != MVT::i64)
return false;
ConstantSDNode *ShlCst = dyn_cast<ConstantSDNode>(Shift.getOperand(1));
if (!ShlCst)
return false;
uint64_t ShAmt = ShlCst->getZExtValue();
// Make sure that we don't change the operation by removing bits.
// This only matters for OR and XOR, AND is unaffected.
uint64_t RemovedBitsMask = (1ULL << ShAmt) - 1;
if (Opcode != ISD::AND && (Val & RemovedBitsMask) != 0)
return false;
// Check the minimum bitwidth for the new constant.
// TODO: Using 16 and 8 bit operations is also possible for or32 & xor32.
auto CanShrinkImmediate = [&](int64_t &ShiftedVal) {
if (Opcode == ISD::AND) {
// AND32ri is the same as AND64ri32 with zext imm.
// Try this before sign extended immediates below.
ShiftedVal = (uint64_t)Val >> ShAmt;
if (NVT == MVT::i64 && !isUInt<32>(Val) && isUInt<32>(ShiftedVal))
return true;
// Also swap order when the AND can become MOVZX.
if (ShiftedVal == UINT8_MAX || ShiftedVal == UINT16_MAX)
return true;
}
ShiftedVal = Val >> ShAmt;
if ((!isInt<8>(Val) && isInt<8>(ShiftedVal)) ||
(!isInt<32>(Val) && isInt<32>(ShiftedVal)))
return true;
if (Opcode != ISD::AND) {
// MOV32ri+OR64r/XOR64r is cheaper than MOV64ri64+OR64rr/XOR64rr
ShiftedVal = (uint64_t)Val >> ShAmt;
if (NVT == MVT::i64 && !isUInt<32>(Val) && isUInt<32>(ShiftedVal))
return true;
}
return false;
};
int64_t ShiftedVal;
if (!CanShrinkImmediate(ShiftedVal))
return false;
// Ok, we can reorder to get a smaller immediate.
// But, its possible the original immediate allowed an AND to become MOVZX.
// Doing this late due to avoid the MakedValueIsZero call as late as
// possible.
if (Opcode == ISD::AND) {
// Find the smallest zext this could possibly be.
unsigned ZExtWidth = Cst->getAPIntValue().getActiveBits();
ZExtWidth = PowerOf2Ceil(std::max(ZExtWidth, 8U));
// Figure out which bits need to be zero to achieve that mask.
APInt NeededMask = APInt::getLowBitsSet(NVT.getSizeInBits(),
ZExtWidth);
NeededMask &= ~Cst->getAPIntValue();
if (CurDAG->MaskedValueIsZero(N->getOperand(0), NeededMask))
return false;
}
SDValue X = Shift.getOperand(0);
if (FoundAnyExtend) {
SDValue NewX = CurDAG->getNode(ISD::ANY_EXTEND, dl, NVT, X);
insertDAGNode(*CurDAG, SDValue(N, 0), NewX);
X = NewX;
}
SDValue NewCst = CurDAG->getConstant(ShiftedVal, dl, NVT);
insertDAGNode(*CurDAG, SDValue(N, 0), NewCst);
SDValue NewBinOp = CurDAG->getNode(Opcode, dl, NVT, X, NewCst);
insertDAGNode(*CurDAG, SDValue(N, 0), NewBinOp);
SDValue NewSHL = CurDAG->getNode(ISD::SHL, dl, NVT, NewBinOp,
Shift.getOperand(1));
ReplaceNode(N, NewSHL.getNode());
SelectCode(NewSHL.getNode());
return true;
}
/// If the high bits of an 'and' operand are known zero, try setting the
/// high bits of an 'and' constant operand to produce a smaller encoding by
/// creating a small, sign-extended negative immediate rather than a large
/// positive one. This reverses a transform in SimplifyDemandedBits that
/// shrinks mask constants by clearing bits. There is also a possibility that
/// the 'and' mask can be made -1, so the 'and' itself is unnecessary. In that
/// case, just replace the 'and'. Return 'true' if the node is replaced.
bool X86DAGToDAGISel::shrinkAndImmediate(SDNode *And) {
// i8 is unshrinkable, i16 should be promoted to i32, and vector ops don't
// have immediate operands.
MVT VT = And->getSimpleValueType(0);
if (VT != MVT::i32 && VT != MVT::i64)
return false;
auto *And1C = dyn_cast<ConstantSDNode>(And->getOperand(1));
if (!And1C)
return false;
// Bail out if the mask constant is already negative. It's can't shrink more.
// If the upper 32 bits of a 64 bit mask are all zeros, we have special isel
// patterns to use a 32-bit and instead of a 64-bit and by relying on the
// implicit zeroing of 32 bit ops. So we should check if the lower 32 bits
// are negative too.
APInt MaskVal = And1C->getAPIntValue();
unsigned MaskLZ = MaskVal.countLeadingZeros();
if (!MaskLZ || (VT == MVT::i64 && MaskLZ == 32))
return false;
// Don't extend into the upper 32 bits of a 64 bit mask.
if (VT == MVT::i64 && MaskLZ >= 32) {
MaskLZ -= 32;
MaskVal = MaskVal.trunc(32);
}
SDValue And0 = And->getOperand(0);
APInt HighZeros = APInt::getHighBitsSet(MaskVal.getBitWidth(), MaskLZ);
APInt NegMaskVal = MaskVal | HighZeros;
// If a negative constant would not allow a smaller encoding, there's no need
// to continue. Only change the constant when we know it's a win.
unsigned MinWidth = NegMaskVal.getMinSignedBits();
if (MinWidth > 32 || (MinWidth > 8 && MaskVal.getMinSignedBits() <= 32))
return false;
// Extend masks if we truncated above.
if (VT == MVT::i64 && MaskVal.getBitWidth() < 64) {
NegMaskVal = NegMaskVal.zext(64);
HighZeros = HighZeros.zext(64);
}
// The variable operand must be all zeros in the top bits to allow using the
// new, negative constant as the mask.
if (!CurDAG->MaskedValueIsZero(And0, HighZeros))
return false;
// Check if the mask is -1. In that case, this is an unnecessary instruction
// that escaped earlier analysis.
if (NegMaskVal.isAllOnesValue()) {
ReplaceNode(And, And0.getNode());
return true;
}
// A negative mask allows a smaller encoding. Create a new 'and' node.
SDValue NewMask = CurDAG->getConstant(NegMaskVal, SDLoc(And), VT);
SDValue NewAnd = CurDAG->getNode(ISD::AND, SDLoc(And), VT, And0, NewMask);
ReplaceNode(And, NewAnd.getNode());
SelectCode(NewAnd.getNode());
return true;
}
static unsigned getVPTESTMOpc(MVT TestVT, bool IsTestN, bool FoldedLoad,
bool FoldedBCast, bool Masked) {
if (Masked) {
if (FoldedLoad) {
switch (TestVT.SimpleTy) {
default: llvm_unreachable("Unexpected VT!");
case MVT::v16i8:
return IsTestN ? X86::VPTESTNMBZ128rmk : X86::VPTESTMBZ128rmk;
case MVT::v8i16:
return IsTestN ? X86::VPTESTNMWZ128rmk : X86::VPTESTMWZ128rmk;
case MVT::v4i32:
return IsTestN ? X86::VPTESTNMDZ128rmk : X86::VPTESTMDZ128rmk;
case MVT::v2i64:
return IsTestN ? X86::VPTESTNMQZ128rmk : X86::VPTESTMQZ128rmk;
case MVT::v32i8:
return IsTestN ? X86::VPTESTNMBZ256rmk : X86::VPTESTMBZ256rmk;
case MVT::v16i16:
return IsTestN ? X86::VPTESTNMWZ256rmk : X86::VPTESTMWZ256rmk;
case MVT::v8i32:
return IsTestN ? X86::VPTESTNMDZ256rmk : X86::VPTESTMDZ256rmk;
case MVT::v4i64:
return IsTestN ? X86::VPTESTNMQZ256rmk : X86::VPTESTMQZ256rmk;
case MVT::v64i8:
return IsTestN ? X86::VPTESTNMBZrmk : X86::VPTESTMBZrmk;
case MVT::v32i16:
return IsTestN ? X86::VPTESTNMWZrmk : X86::VPTESTMWZrmk;
case MVT::v16i32:
return IsTestN ? X86::VPTESTNMDZrmk : X86::VPTESTMDZrmk;
case MVT::v8i64:
return IsTestN ? X86::VPTESTNMQZrmk : X86::VPTESTMQZrmk;
}
}
if (FoldedBCast) {
switch (TestVT.SimpleTy) {
default: llvm_unreachable("Unexpected VT!");
case MVT::v4i32:
return IsTestN ? X86::VPTESTNMDZ128rmbk : X86::VPTESTMDZ128rmbk;
case MVT::v2i64:
return IsTestN ? X86::VPTESTNMQZ128rmbk : X86::VPTESTMQZ128rmbk;
case MVT::v8i32:
return IsTestN ? X86::VPTESTNMDZ256rmbk : X86::VPTESTMDZ256rmbk;
case MVT::v4i64:
return IsTestN ? X86::VPTESTNMQZ256rmbk : X86::VPTESTMQZ256rmbk;
case MVT::v16i32:
return IsTestN ? X86::VPTESTNMDZrmbk : X86::VPTESTMDZrmbk;
case MVT::v8i64:
return IsTestN ? X86::VPTESTNMQZrmbk : X86::VPTESTMQZrmbk;
}
}
switch (TestVT.SimpleTy) {
default: llvm_unreachable("Unexpected VT!");
case MVT::v16i8:
return IsTestN ? X86::VPTESTNMBZ128rrk : X86::VPTESTMBZ128rrk;
case MVT::v8i16:
return IsTestN ? X86::VPTESTNMWZ128rrk : X86::VPTESTMWZ128rrk;
case MVT::v4i32:
return IsTestN ? X86::VPTESTNMDZ128rrk : X86::VPTESTMDZ128rrk;
case MVT::v2i64:
return IsTestN ? X86::VPTESTNMQZ128rrk : X86::VPTESTMQZ128rrk;
case MVT::v32i8:
return IsTestN ? X86::VPTESTNMBZ256rrk : X86::VPTESTMBZ256rrk;
case MVT::v16i16:
return IsTestN ? X86::VPTESTNMWZ256rrk : X86::VPTESTMWZ256rrk;
case MVT::v8i32:
return IsTestN ? X86::VPTESTNMDZ256rrk : X86::VPTESTMDZ256rrk;
case MVT::v4i64:
return IsTestN ? X86::VPTESTNMQZ256rrk : X86::VPTESTMQZ256rrk;
case MVT::v64i8:
return IsTestN ? X86::VPTESTNMBZrrk : X86::VPTESTMBZrrk;
case MVT::v32i16:
return IsTestN ? X86::VPTESTNMWZrrk : X86::VPTESTMWZrrk;
case MVT::v16i32:
return IsTestN ? X86::VPTESTNMDZrrk : X86::VPTESTMDZrrk;
case MVT::v8i64:
return IsTestN ? X86::VPTESTNMQZrrk : X86::VPTESTMQZrrk;
}
}
if (FoldedLoad) {
switch (TestVT.SimpleTy) {
default: llvm_unreachable("Unexpected VT!");
case MVT::v16i8:
return IsTestN ? X86::VPTESTNMBZ128rm : X86::VPTESTMBZ128rm;
case MVT::v8i16:
return IsTestN ? X86::VPTESTNMWZ128rm : X86::VPTESTMWZ128rm;
case MVT::v4i32:
return IsTestN ? X86::VPTESTNMDZ128rm : X86::VPTESTMDZ128rm;
case MVT::v2i64:
return IsTestN ? X86::VPTESTNMQZ128rm : X86::VPTESTMQZ128rm;
case MVT::v32i8:
return IsTestN ? X86::VPTESTNMBZ256rm : X86::VPTESTMBZ256rm;
case MVT::v16i16:
return IsTestN ? X86::VPTESTNMWZ256rm : X86::VPTESTMWZ256rm;
case MVT::v8i32:
return IsTestN ? X86::VPTESTNMDZ256rm : X86::VPTESTMDZ256rm;
case MVT::v4i64:
return IsTestN ? X86::VPTESTNMQZ256rm : X86::VPTESTMQZ256rm;
case MVT::v64i8:
return IsTestN ? X86::VPTESTNMBZrm : X86::VPTESTMBZrm;
case MVT::v32i16:
return IsTestN ? X86::VPTESTNMWZrm : X86::VPTESTMWZrm;
case MVT::v16i32:
return IsTestN ? X86::VPTESTNMDZrm : X86::VPTESTMDZrm;
case MVT::v8i64:
return IsTestN ? X86::VPTESTNMQZrm : X86::VPTESTMQZrm;
}
}
if (FoldedBCast) {
switch (TestVT.SimpleTy) {
default: llvm_unreachable("Unexpected VT!");
case MVT::v4i32:
return IsTestN ? X86::VPTESTNMDZ128rmb : X86::VPTESTMDZ128rmb;
case MVT::v2i64:
return IsTestN ? X86::VPTESTNMQZ128rmb : X86::VPTESTMQZ128rmb;
case MVT::v8i32:
return IsTestN ? X86::VPTESTNMDZ256rmb : X86::VPTESTMDZ256rmb;
case MVT::v4i64:
return IsTestN ? X86::VPTESTNMQZ256rmb : X86::VPTESTMQZ256rmb;
case MVT::v16i32:
return IsTestN ? X86::VPTESTNMDZrmb : X86::VPTESTMDZrmb;
case MVT::v8i64:
return IsTestN ? X86::VPTESTNMQZrmb : X86::VPTESTMQZrmb;
}
}
switch (TestVT.SimpleTy) {
default: llvm_unreachable("Unexpected VT!");
case MVT::v16i8:
return IsTestN ? X86::VPTESTNMBZ128rr : X86::VPTESTMBZ128rr;
case MVT::v8i16:
return IsTestN ? X86::VPTESTNMWZ128rr : X86::VPTESTMWZ128rr;
case MVT::v4i32:
return IsTestN ? X86::VPTESTNMDZ128rr : X86::VPTESTMDZ128rr;
case MVT::v2i64:
return IsTestN ? X86::VPTESTNMQZ128rr : X86::VPTESTMQZ128rr;
case MVT::v32i8:
return IsTestN ? X86::VPTESTNMBZ256rr : X86::VPTESTMBZ256rr;
case MVT::v16i16:
return IsTestN ? X86::VPTESTNMWZ256rr : X86::VPTESTMWZ256rr;
case MVT::v8i32:
return IsTestN ? X86::VPTESTNMDZ256rr : X86::VPTESTMDZ256rr;
case MVT::v4i64:
return IsTestN ? X86::VPTESTNMQZ256rr : X86::VPTESTMQZ256rr;
case MVT::v64i8:
return IsTestN ? X86::VPTESTNMBZrr : X86::VPTESTMBZrr;
case MVT::v32i16:
return IsTestN ? X86::VPTESTNMWZrr : X86::VPTESTMWZrr;
case MVT::v16i32:
return IsTestN ? X86::VPTESTNMDZrr : X86::VPTESTMDZrr;
case MVT::v8i64:
return IsTestN ? X86::VPTESTNMQZrr : X86::VPTESTMQZrr;
}
}
// Try to create VPTESTM instruction. If InMask is not null, it will be used
// to form a masked operation.
bool X86DAGToDAGISel::tryVPTESTM(SDNode *Root, SDValue Setcc,
SDValue InMask) {
assert(Subtarget->hasAVX512() && "Expected AVX512!");
assert(Setcc.getSimpleValueType().getVectorElementType() == MVT::i1 &&
"Unexpected VT!");
// Look for equal and not equal compares.
ISD::CondCode CC = cast<CondCodeSDNode>(Setcc.getOperand(2))->get();
if (CC != ISD::SETEQ && CC != ISD::SETNE)
return false;
// See if we're comparing against zero. This should have been canonicalized
// to RHS during lowering.
if (!ISD::isBuildVectorAllZeros(Setcc.getOperand(1).getNode()))
return false;
SDValue N0 = Setcc.getOperand(0);
MVT CmpVT = N0.getSimpleValueType();
MVT CmpSVT = CmpVT.getVectorElementType();
// Start with both operands the same. We'll try to refine this.
SDValue Src0 = N0;
SDValue Src1 = N0;
{
// Look through single use bitcasts.
SDValue N0Temp = N0;
if (N0Temp.getOpcode() == ISD::BITCAST && N0Temp.hasOneUse())
N0Temp = N0.getOperand(0);
// Look for single use AND.
if (N0Temp.getOpcode() == ISD::AND && N0Temp.hasOneUse()) {
Src0 = N0Temp.getOperand(0);
Src1 = N0Temp.getOperand(1);
}
}
// Without VLX we need to widen the load.
bool Widen = !Subtarget->hasVLX() && !CmpVT.is512BitVector();
// We can only fold loads if the sources are unique.
bool CanFoldLoads = Src0 != Src1;
// Try to fold loads unless we need to widen.
bool FoldedLoad = false;
SDValue Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, Load;
if (!Widen && CanFoldLoads) {
Load = Src1;
FoldedLoad = tryFoldLoad(Root, N0.getNode(), Load, Tmp0, Tmp1, Tmp2, Tmp3,
Tmp4);
if (!FoldedLoad) {
// And is computative.
Load = Src0;
FoldedLoad = tryFoldLoad(Root, N0.getNode(), Load, Tmp0, Tmp1, Tmp2,
Tmp3, Tmp4);
if (FoldedLoad)
std::swap(Src0, Src1);
}
}
auto findBroadcastedOp = [](SDValue Src, MVT CmpSVT, SDNode *&Parent) {
// Look through single use bitcasts.
if (Src.getOpcode() == ISD::BITCAST && Src.hasOneUse())
Src = Src.getOperand(0);
if (Src.getOpcode() == X86ISD::VBROADCAST && Src.hasOneUse()) {
Parent = Src.getNode();
Src = Src.getOperand(0);
if (Src.getSimpleValueType() == CmpSVT)
return Src;
}
return SDValue();
};
// If we didn't fold a load, try to match broadcast. No widening limitation
// for this. But only 32 and 64 bit types are supported.
bool FoldedBCast = false;
if (!FoldedLoad && CanFoldLoads &&
(CmpSVT == MVT::i32 || CmpSVT == MVT::i64)) {
SDNode *ParentNode = nullptr;
if ((Load = findBroadcastedOp(Src1, CmpSVT, ParentNode))) {
FoldedBCast = tryFoldLoad(Root, ParentNode, Load, Tmp0,
Tmp1, Tmp2, Tmp3, Tmp4);
}
// Try the other operand.
if (!FoldedBCast) {
if ((Load = findBroadcastedOp(Src0, CmpSVT, ParentNode))) {
FoldedBCast = tryFoldLoad(Root, ParentNode, Load, Tmp0,
Tmp1, Tmp2, Tmp3, Tmp4);
if (FoldedBCast)
std::swap(Src0, Src1);
}
}
}
auto getMaskRC = [](MVT MaskVT) {
switch (MaskVT.SimpleTy) {
default: llvm_unreachable("Unexpected VT!");
case MVT::v2i1: return X86::VK2RegClassID;
case MVT::v4i1: return X86::VK4RegClassID;
case MVT::v8i1: return X86::VK8RegClassID;
case MVT::v16i1: return X86::VK16RegClassID;
case MVT::v32i1: return X86::VK32RegClassID;
case MVT::v64i1: return X86::VK64RegClassID;
}
};
bool IsMasked = InMask.getNode() != nullptr;
SDLoc dl(Root);
MVT ResVT = Setcc.getSimpleValueType();
MVT MaskVT = ResVT;
if (Widen) {
// Widen the inputs using insert_subreg or copy_to_regclass.
unsigned Scale = CmpVT.is128BitVector() ? 4 : 2;
unsigned SubReg = CmpVT.is128BitVector() ? X86::sub_xmm : X86::sub_ymm;
unsigned NumElts = CmpVT.getVectorNumElements() * Scale;
CmpVT = MVT::getVectorVT(CmpSVT, NumElts);
MaskVT = MVT::getVectorVT(MVT::i1, NumElts);
SDValue ImplDef = SDValue(CurDAG->getMachineNode(X86::IMPLICIT_DEF, dl,
CmpVT), 0);
Src0 = CurDAG->getTargetInsertSubreg(SubReg, dl, CmpVT, ImplDef, Src0);
assert(!FoldedLoad && "Shouldn't have folded the load");
if (!FoldedBCast)
Src1 = CurDAG->getTargetInsertSubreg(SubReg, dl, CmpVT, ImplDef, Src1);
if (IsMasked) {
// Widen the mask.
unsigned RegClass = getMaskRC(MaskVT);
SDValue RC = CurDAG->getTargetConstant(RegClass, dl, MVT::i32);
InMask = SDValue(CurDAG->getMachineNode(TargetOpcode::COPY_TO_REGCLASS,
dl, MaskVT, InMask, RC), 0);
}
}
bool IsTestN = CC == ISD::SETEQ;
unsigned Opc = getVPTESTMOpc(CmpVT, IsTestN, FoldedLoad, FoldedBCast,
IsMasked);
MachineSDNode *CNode;
if (FoldedLoad || FoldedBCast) {
SDVTList VTs = CurDAG->getVTList(MaskVT, MVT::Other);
if (IsMasked) {
SDValue Ops[] = { InMask, Src0, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4,
Load.getOperand(0) };
CNode = CurDAG->getMachineNode(Opc, dl, VTs, Ops);
} else {
SDValue Ops[] = { Src0, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4,
Load.getOperand(0) };
CNode = CurDAG->getMachineNode(Opc, dl, VTs, Ops);
}
// Update the chain.
ReplaceUses(Load.getValue(1), SDValue(CNode, 1));
// Record the mem-refs
CurDAG->setNodeMemRefs(CNode, {cast<LoadSDNode>(Load)->getMemOperand()});
} else {
if (IsMasked)
CNode = CurDAG->getMachineNode(Opc, dl, MaskVT, InMask, Src0, Src1);
else
CNode = CurDAG->getMachineNode(Opc, dl, MaskVT, Src0, Src1);
}
// If we widened, we need to shrink the mask VT.
if (Widen) {
unsigned RegClass = getMaskRC(ResVT);
SDValue RC = CurDAG->getTargetConstant(RegClass, dl, MVT::i32);
CNode = CurDAG->getMachineNode(TargetOpcode::COPY_TO_REGCLASS,
dl, ResVT, SDValue(CNode, 0), RC);
}
ReplaceUses(SDValue(Root, 0), SDValue(CNode, 0));
CurDAG->RemoveDeadNode(Root);
return true;
}
void X86DAGToDAGISel::Select(SDNode *Node) {
MVT NVT = Node->getSimpleValueType(0);
unsigned Opcode = Node->getOpcode();
SDLoc dl(Node);
if (Node->isMachineOpcode()) {
LLVM_DEBUG(dbgs() << "== "; Node->dump(CurDAG); dbgs() << '\n');
Node->setNodeId(-1);
return; // Already selected.
}
switch (Opcode) {
default: break;
case ISD::INTRINSIC_VOID: {
unsigned IntNo = Node->getConstantOperandVal(1);
switch (IntNo) {
default: break;
case Intrinsic::x86_sse3_monitor:
case Intrinsic::x86_monitorx:
case Intrinsic::x86_clzero: {
bool Use64BitPtr = Node->getOperand(2).getValueType() == MVT::i64;
unsigned Opc = 0;
switch (IntNo) {
case Intrinsic::x86_sse3_monitor:
if (!Subtarget->hasSSE3())
break;
Opc = Use64BitPtr ? X86::MONITOR64rrr : X86::MONITOR32rrr;
break;
case Intrinsic::x86_monitorx:
if (!Subtarget->hasMWAITX())
break;
Opc = Use64BitPtr ? X86::MONITORX64rrr : X86::MONITORX32rrr;
break;
case Intrinsic::x86_clzero:
if (!Subtarget->hasCLZERO())
break;
Opc = Use64BitPtr ? X86::CLZERO64r : X86::CLZERO32r;
break;
}
if (Opc) {
unsigned PtrReg = Use64BitPtr ? X86::RAX : X86::EAX;
SDValue Chain = CurDAG->getCopyToReg(Node->getOperand(0), dl, PtrReg,
Node->getOperand(2), SDValue());
SDValue InFlag = Chain.getValue(1);
if (IntNo == Intrinsic::x86_sse3_monitor ||
IntNo == Intrinsic::x86_monitorx) {
// Copy the other two operands to ECX and EDX.
Chain = CurDAG->getCopyToReg(Chain, dl, X86::ECX, Node->getOperand(3),
InFlag);
InFlag = Chain.getValue(1);
Chain = CurDAG->getCopyToReg(Chain, dl, X86::EDX, Node->getOperand(4),
InFlag);
InFlag = Chain.getValue(1);
}
MachineSDNode *CNode = CurDAG->getMachineNode(Opc, dl, MVT::Other,
{ Chain, InFlag});
ReplaceNode(Node, CNode);
return;
}
}
}
break;
}
case ISD::BRIND: {
if (Subtarget->isTargetNaCl())
// NaCl has its own pass where jmp %r32 are converted to jmp %r64. We
// leave the instruction alone.
break;
if (Subtarget->isTarget64BitILP32()) {
// Converts a 32-bit register to a 64-bit, zero-extended version of
// it. This is needed because x86-64 can do many things, but jmp %r32
// ain't one of them.
const SDValue &Target = Node->getOperand(1);
assert(Target.getSimpleValueType() == llvm::MVT::i32);
SDValue ZextTarget = CurDAG->getZExtOrTrunc(Target, dl, EVT(MVT::i64));
SDValue Brind = CurDAG->getNode(ISD::BRIND, dl, MVT::Other,
Node->getOperand(0), ZextTarget);
ReplaceNode(Node, Brind.getNode());
SelectCode(ZextTarget.getNode());
SelectCode(Brind.getNode());
return;
}
break;
}
case X86ISD::GlobalBaseReg:
ReplaceNode(Node, getGlobalBaseReg());
return;
case ISD::BITCAST:
// Just drop all 128/256/512-bit bitcasts.
if (NVT.is512BitVector() || NVT.is256BitVector() || NVT.is128BitVector() ||
NVT == MVT::f128) {
ReplaceUses(SDValue(Node, 0), Node->getOperand(0));
CurDAG->RemoveDeadNode(Node);
return;
}
break;
case ISD::VSELECT: {
// Replace VSELECT with non-mask conditions with with BLENDV.
if (Node->getOperand(0).getValueType().getVectorElementType() == MVT::i1)
break;
assert(Subtarget->hasSSE41() && "Expected SSE4.1 support!");
SDValue Blendv = CurDAG->getNode(
X86ISD::BLENDV, SDLoc(Node), Node->getValueType(0), Node->getOperand(0),
Node->getOperand(1), Node->getOperand(2));
ReplaceNode(Node, Blendv.getNode());
SelectCode(Blendv.getNode());
// We already called ReplaceUses.
return;
}
case ISD::SRL:
if (matchBitExtract(Node))
return;
LLVM_FALLTHROUGH;
case ISD::SRA:
case ISD::SHL:
if (tryShiftAmountMod(Node))
return;
break;
case ISD::AND:
if (NVT.isVector() && NVT.getVectorElementType() == MVT::i1) {
// Try to form a masked VPTESTM. Operands can be in either order.
SDValue N0 = Node->getOperand(0);
SDValue N1 = Node->getOperand(1);
if (N0.getOpcode() == ISD::SETCC && N0.hasOneUse() &&
tryVPTESTM(Node, N0, N1))
return;
if (N1.getOpcode() == ISD::SETCC && N1.hasOneUse() &&
tryVPTESTM(Node, N1, N0))
return;
}
if (MachineSDNode *NewNode = matchBEXTRFromAndImm(Node)) {
ReplaceUses(SDValue(Node, 0), SDValue(NewNode, 0));
CurDAG->RemoveDeadNode(Node);
return;
}
if (matchBitExtract(Node))
return;
if (AndImmShrink && shrinkAndImmediate(Node))
return;
LLVM_FALLTHROUGH;
case ISD::OR:
case ISD::XOR:
if (tryShrinkShlLogicImm(Node))
return;
LLVM_FALLTHROUGH;
case ISD::ADD:
case ISD::SUB: {
// Try to avoid folding immediates with multiple uses for optsize.
// This code tries to select to register form directly to avoid going
// through the isel table which might fold the immediate. We can't change
// the patterns on the add/sub/and/or/xor with immediate paterns in the
// tablegen files to check immediate use count without making the patterns
// unavailable to the fast-isel table.
if (!OptForSize)
break;
// Only handle i8/i16/i32/i64.
if (NVT != MVT::i8 && NVT != MVT::i16 && NVT != MVT::i32 && NVT != MVT::i64)
break;
SDValue N0 = Node->getOperand(0);
SDValue N1 = Node->getOperand(1);
ConstantSDNode *Cst = dyn_cast<ConstantSDNode>(N1);
if (!Cst)
break;
int64_t Val = Cst->getSExtValue();
// Make sure its an immediate that is considered foldable.
// FIXME: Handle unsigned 32 bit immediates for 64-bit AND.
if (!isInt<8>(Val) && !isInt<32>(Val))
break;
// Check if we should avoid folding this immediate.
if (!shouldAvoidImmediateInstFormsForSize(N1.getNode()))
break;
// We should not fold the immediate. So we need a register form instead.
unsigned ROpc, MOpc;
switch (NVT.SimpleTy) {
default: llvm_unreachable("Unexpected VT!");
case MVT::i8:
switch (Opcode) {
default: llvm_unreachable("Unexpected opcode!");
case ISD::ADD: ROpc = X86::ADD8rr; MOpc = X86::ADD8rm; break;
case ISD::SUB: ROpc = X86::SUB8rr; MOpc = X86::SUB8rm; break;
case ISD::AND: ROpc = X86::AND8rr; MOpc = X86::AND8rm; break;
case ISD::OR: ROpc = X86::OR8rr; MOpc = X86::OR8rm; break;
case ISD::XOR: ROpc = X86::XOR8rr; MOpc = X86::XOR8rm; break;
}
break;
case MVT::i16:
switch (Opcode) {
default: llvm_unreachable("Unexpected opcode!");
case ISD::ADD: ROpc = X86::ADD16rr; MOpc = X86::ADD16rm; break;
case ISD::SUB: ROpc = X86::SUB16rr; MOpc = X86::SUB16rm; break;
case ISD::AND: ROpc = X86::AND16rr; MOpc = X86::AND16rm; break;
case ISD::OR: ROpc = X86::OR16rr; MOpc = X86::OR16rm; break;
case ISD::XOR: ROpc = X86::XOR16rr; MOpc = X86::XOR16rm; break;
}
break;
case MVT::i32:
switch (Opcode) {
default: llvm_unreachable("Unexpected opcode!");
case ISD::ADD: ROpc = X86::ADD32rr; MOpc = X86::ADD32rm; break;
case ISD::SUB: ROpc = X86::SUB32rr; MOpc = X86::SUB32rm; break;
case ISD::AND: ROpc = X86::AND32rr; MOpc = X86::AND32rm; break;
case ISD::OR: ROpc = X86::OR32rr; MOpc = X86::OR32rm; break;
case ISD::XOR: ROpc = X86::XOR32rr; MOpc = X86::XOR32rm; break;
}
break;
case MVT::i64:
switch (Opcode) {
default: llvm_unreachable("Unexpected opcode!");
case ISD::ADD: ROpc = X86::ADD64rr; MOpc = X86::ADD64rm; break;
case ISD::SUB: ROpc = X86::SUB64rr; MOpc = X86::SUB64rm; break;
case ISD::AND: ROpc = X86::AND64rr; MOpc = X86::AND64rm; break;
case ISD::OR: ROpc = X86::OR64rr; MOpc = X86::OR64rm; break;
case ISD::XOR: ROpc = X86::XOR64rr; MOpc = X86::XOR64rm; break;
}
break;
}
// Ok this is a AND/OR/XOR/ADD/SUB with constant.
// If this is a not a subtract, we can still try to fold a load.
if (Opcode != ISD::SUB) {
SDValue Tmp0, Tmp1, Tmp2, Tmp3, Tmp4;
if (tryFoldLoad(Node, N0, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4)) {
SDValue Ops[] = { N1, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, N0.getOperand(0) };
SDVTList VTs = CurDAG->getVTList(NVT, MVT::i32, MVT::Other);
MachineSDNode *CNode = CurDAG->getMachineNode(MOpc, dl, VTs, Ops);
// Update the chain.
ReplaceUses(N0.getValue(1), SDValue(CNode, 2));
// Record the mem-refs
CurDAG->setNodeMemRefs(CNode, {cast<LoadSDNode>(N0)->getMemOperand()});
ReplaceUses(SDValue(Node, 0), SDValue(CNode, 0));
CurDAG->RemoveDeadNode(Node);
return;
}
}
CurDAG->SelectNodeTo(Node, ROpc, NVT, MVT::i32, N0, N1);
return;
}
case X86ISD::SMUL:
// i16/i32/i64 are handled with isel patterns.
if (NVT != MVT::i8)
break;
LLVM_FALLTHROUGH;
case X86ISD::UMUL: {
SDValue N0 = Node->getOperand(0);
SDValue N1 = Node->getOperand(1);
unsigned LoReg, ROpc, MOpc;
switch (NVT.SimpleTy) {
default: llvm_unreachable("Unsupported VT!");
case MVT::i8:
LoReg = X86::AL;
ROpc = Opcode == X86ISD::SMUL ? X86::IMUL8r : X86::MUL8r;
MOpc = Opcode == X86ISD::SMUL ? X86::IMUL8m : X86::MUL8m;
break;
case MVT::i16:
LoReg = X86::AX;
ROpc = X86::MUL16r;
MOpc = X86::MUL16m;
break;
case MVT::i32:
LoReg = X86::EAX;
ROpc = X86::MUL32r;
MOpc = X86::MUL32m;
break;
case MVT::i64:
LoReg = X86::RAX;
ROpc = X86::MUL64r;
MOpc = X86::MUL64m;
break;
}
SDValue Tmp0, Tmp1, Tmp2, Tmp3, Tmp4;
bool FoldedLoad = tryFoldLoad(Node, N1, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4);
// Multiply is commmutative.
if (!FoldedLoad) {
FoldedLoad = tryFoldLoad(Node, N0, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4);
if (FoldedLoad)
std::swap(N0, N1);
}
SDValue InFlag = CurDAG->getCopyToReg(CurDAG->getEntryNode(), dl, LoReg,
N0, SDValue()).getValue(1);
MachineSDNode *CNode;
if (FoldedLoad) {
// i16/i32/i64 use an instruction that produces a low and high result even
// though only the low result is used.
SDVTList VTs;
if (NVT == MVT::i8)
VTs = CurDAG->getVTList(NVT, MVT::i32, MVT::Other);
else
VTs = CurDAG->getVTList(NVT, NVT, MVT::i32, MVT::Other);
SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, N1.getOperand(0),
InFlag };
CNode = CurDAG->getMachineNode(MOpc, dl, VTs, Ops);
// Update the chain.
ReplaceUses(N1.getValue(1), SDValue(CNode, NVT == MVT::i8 ? 2 : 3));
// Record the mem-refs
CurDAG->setNodeMemRefs(CNode, {cast<LoadSDNode>(N1)->getMemOperand()});
} else {
// i16/i32/i64 use an instruction that produces a low and high result even
// though only the low result is used.
SDVTList VTs;
if (NVT == MVT::i8)
VTs = CurDAG->getVTList(NVT, MVT::i32);
else
VTs = CurDAG->getVTList(NVT, NVT, MVT::i32);
CNode = CurDAG->getMachineNode(ROpc, dl, VTs, {N1, InFlag});
}
ReplaceUses(SDValue(Node, 0), SDValue(CNode, 0));
ReplaceUses(SDValue(Node, 1), SDValue(CNode, NVT == MVT::i8 ? 1 : 2));
CurDAG->RemoveDeadNode(Node);
return;
}
case ISD::SMUL_LOHI:
case ISD::UMUL_LOHI: {
SDValue N0 = Node->getOperand(0);
SDValue N1 = Node->getOperand(1);
unsigned Opc, MOpc;
bool isSigned = Opcode == ISD::SMUL_LOHI;
if (!isSigned) {
switch (NVT.SimpleTy) {
default: llvm_unreachable("Unsupported VT!");
case MVT::i32: Opc = X86::MUL32r; MOpc = X86::MUL32m; break;
case MVT::i64: Opc = X86::MUL64r; MOpc = X86::MUL64m; break;
}
} else {
switch (NVT.SimpleTy) {
default: llvm_unreachable("Unsupported VT!");
case MVT::i32: Opc = X86::IMUL32r; MOpc = X86::IMUL32m; break;
case MVT::i64: Opc = X86::IMUL64r; MOpc = X86::IMUL64m; break;
}
}
unsigned SrcReg, LoReg, HiReg;
switch (Opc) {
default: llvm_unreachable("Unknown MUL opcode!");
case X86::IMUL32r:
case X86::MUL32r:
SrcReg = LoReg = X86::EAX; HiReg = X86::EDX;
break;
case X86::IMUL64r:
case X86::MUL64r:
SrcReg = LoReg = X86::RAX; HiReg = X86::RDX;
break;
}
SDValue Tmp0, Tmp1, Tmp2, Tmp3, Tmp4;
bool foldedLoad = tryFoldLoad(Node, N1, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4);
// Multiply is commmutative.
if (!foldedLoad) {
foldedLoad = tryFoldLoad(Node, N0, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4);
if (foldedLoad)
std::swap(N0, N1);
}
SDValue InFlag = CurDAG->getCopyToReg(CurDAG->getEntryNode(), dl, SrcReg,
N0, SDValue()).getValue(1);
if (foldedLoad) {
SDValue Chain;
MachineSDNode *CNode = nullptr;
SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, N1.getOperand(0),
InFlag };
SDVTList VTs = CurDAG->getVTList(MVT::Other, MVT::Glue);
CNode = CurDAG->getMachineNode(MOpc, dl, VTs, Ops);
Chain = SDValue(CNode, 0);
InFlag = SDValue(CNode, 1);
// Update the chain.
ReplaceUses(N1.getValue(1), Chain);
// Record the mem-refs
CurDAG->setNodeMemRefs(CNode, {cast<LoadSDNode>(N1)->getMemOperand()});
} else {
SDValue Ops[] = { N1, InFlag };
SDVTList VTs = CurDAG->getVTList(MVT::Glue);
SDNode *CNode = CurDAG->getMachineNode(Opc, dl, VTs, Ops);
InFlag = SDValue(CNode, 0);
}
// Copy the low half of the result, if it is needed.
if (!SDValue(Node, 0).use_empty()) {
assert(LoReg && "Register for low half is not defined!");
SDValue ResLo = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl, LoReg,
NVT, InFlag);
InFlag = ResLo.getValue(2);
ReplaceUses(SDValue(Node, 0), ResLo);
LLVM_DEBUG(dbgs() << "=> "; ResLo.getNode()->dump(CurDAG);
dbgs() << '\n');
}
// Copy the high half of the result, if it is needed.
if (!SDValue(Node, 1).use_empty()) {
assert(HiReg && "Register for high half is not defined!");
SDValue ResHi = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl, HiReg,
NVT, InFlag);
InFlag = ResHi.getValue(2);
ReplaceUses(SDValue(Node, 1), ResHi);
LLVM_DEBUG(dbgs() << "=> "; ResHi.getNode()->dump(CurDAG);
dbgs() << '\n');
}
CurDAG->RemoveDeadNode(Node);
return;
}
case ISD::SDIVREM:
case ISD::UDIVREM: {
SDValue N0 = Node->getOperand(0);
SDValue N1 = Node->getOperand(1);
unsigned Opc, MOpc;
bool isSigned = Opcode == ISD::SDIVREM;
if (!isSigned) {
switch (NVT.SimpleTy) {
default: llvm_unreachable("Unsupported VT!");
case MVT::i8: Opc = X86::DIV8r; MOpc = X86::DIV8m; break;
case MVT::i16: Opc = X86::DIV16r; MOpc = X86::DIV16m; break;
case MVT::i32: Opc = X86::DIV32r; MOpc = X86::DIV32m; break;
case MVT::i64: Opc = X86::DIV64r; MOpc = X86::DIV64m; break;
}
} else {
switch (NVT.SimpleTy) {
default: llvm_unreachable("Unsupported VT!");
case MVT::i8: Opc = X86::IDIV8r; MOpc = X86::IDIV8m; break;
case MVT::i16: Opc = X86::IDIV16r; MOpc = X86::IDIV16m; break;
case MVT::i32: Opc = X86::IDIV32r; MOpc = X86::IDIV32m; break;
case MVT::i64: Opc = X86::IDIV64r; MOpc = X86::IDIV64m; break;
}
}
unsigned LoReg, HiReg, ClrReg;
unsigned SExtOpcode;
switch (NVT.SimpleTy) {
default: llvm_unreachable("Unsupported VT!");
case MVT::i8:
LoReg = X86::AL; ClrReg = HiReg = X86::AH;
SExtOpcode = X86::CBW;
break;
case MVT::i16:
LoReg = X86::AX; HiReg = X86::DX;
ClrReg = X86::DX;
SExtOpcode = X86::CWD;
break;
case MVT::i32:
LoReg = X86::EAX; ClrReg = HiReg = X86::EDX;
SExtOpcode = X86::CDQ;
break;
case MVT::i64:
LoReg = X86::RAX; ClrReg = HiReg = X86::RDX;
SExtOpcode = X86::CQO;
break;
}
SDValue Tmp0, Tmp1, Tmp2, Tmp3, Tmp4;
bool foldedLoad = tryFoldLoad(Node, N1, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4);
bool signBitIsZero = CurDAG->SignBitIsZero(N0);
SDValue InFlag;
if (NVT == MVT::i8 && (!isSigned || signBitIsZero)) {
// Special case for div8, just use a move with zero extension to AX to
// clear the upper 8 bits (AH).
SDValue Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, Chain;
MachineSDNode *Move;
if (tryFoldLoad(Node, N0, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4)) {
SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, N0.getOperand(0) };
Move = CurDAG->getMachineNode(X86::MOVZX32rm8, dl, MVT::i32,
MVT::Other, Ops);
Chain = SDValue(Move, 1);
ReplaceUses(N0.getValue(1), Chain);
// Record the mem-refs
CurDAG->setNodeMemRefs(Move, {cast<LoadSDNode>(N0)->getMemOperand()});
} else {
Move = CurDAG->getMachineNode(X86::MOVZX32rr8, dl, MVT::i32, N0);
Chain = CurDAG->getEntryNode();
}
Chain = CurDAG->getCopyToReg(Chain, dl, X86::EAX, SDValue(Move, 0),
SDValue());
InFlag = Chain.getValue(1);
} else {
InFlag =
CurDAG->getCopyToReg(CurDAG->getEntryNode(), dl,
LoReg, N0, SDValue()).getValue(1);
if (isSigned && !signBitIsZero) {
// Sign extend the low part into the high part.
InFlag =
SDValue(CurDAG->getMachineNode(SExtOpcode, dl, MVT::Glue, InFlag),0);
} else {
// Zero out the high part, effectively zero extending the input.
SDValue ClrNode = SDValue(CurDAG->getMachineNode(X86::MOV32r0, dl, NVT), 0);
switch (NVT.SimpleTy) {
case MVT::i16:
ClrNode =
SDValue(CurDAG->getMachineNode(
TargetOpcode::EXTRACT_SUBREG, dl, MVT::i16, ClrNode,
CurDAG->getTargetConstant(X86::sub_16bit, dl,
MVT::i32)),
0);
break;
case MVT::i32:
break;
case MVT::i64:
ClrNode =
SDValue(CurDAG->getMachineNode(
TargetOpcode::SUBREG_TO_REG, dl, MVT::i64,
CurDAG->getTargetConstant(0, dl, MVT::i64), ClrNode,
CurDAG->getTargetConstant(X86::sub_32bit, dl,
MVT::i32)),
0);
break;
default:
llvm_unreachable("Unexpected division source");
}
InFlag = CurDAG->getCopyToReg(CurDAG->getEntryNode(), dl, ClrReg,
ClrNode, InFlag).getValue(1);
}
}
if (foldedLoad) {
SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, N1.getOperand(0),
InFlag };
MachineSDNode *CNode =
CurDAG->getMachineNode(MOpc, dl, MVT::Other, MVT::Glue, Ops);
InFlag = SDValue(CNode, 1);
// Update the chain.
ReplaceUses(N1.getValue(1), SDValue(CNode, 0));
// Record the mem-refs
CurDAG->setNodeMemRefs(CNode, {cast<LoadSDNode>(N1)->getMemOperand()});
} else {
InFlag =
SDValue(CurDAG->getMachineNode(Opc, dl, MVT::Glue, N1, InFlag), 0);
}
// Prevent use of AH in a REX instruction by explicitly copying it to
// an ABCD_L register.
//
// The current assumption of the register allocator is that isel
// won't generate explicit references to the GR8_ABCD_H registers. If
// the allocator and/or the backend get enhanced to be more robust in
// that regard, this can be, and should be, removed.
if (HiReg == X86::AH && !SDValue(Node, 1).use_empty()) {
SDValue AHCopy = CurDAG->getRegister(X86::AH, MVT::i8);
unsigned AHExtOpcode =
isSigned ? X86::MOVSX32rr8_NOREX : X86::MOVZX32rr8_NOREX;
SDNode *RNode = CurDAG->getMachineNode(AHExtOpcode, dl, MVT::i32,
MVT::Glue, AHCopy, InFlag);
SDValue Result(RNode, 0);
InFlag = SDValue(RNode, 1);
Result =
CurDAG->getTargetExtractSubreg(X86::sub_8bit, dl, MVT::i8, Result);
ReplaceUses(SDValue(Node, 1), Result);
LLVM_DEBUG(dbgs() << "=> "; Result.getNode()->dump(CurDAG);
dbgs() << '\n');
}
// Copy the division (low) result, if it is needed.
if (!SDValue(Node, 0).use_empty()) {
SDValue Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl,
LoReg, NVT, InFlag);
InFlag = Result.getValue(2);
ReplaceUses(SDValue(Node, 0), Result);
LLVM_DEBUG(dbgs() << "=> "; Result.getNode()->dump(CurDAG);
dbgs() << '\n');
}
// Copy the remainder (high) result, if it is needed.
if (!SDValue(Node, 1).use_empty()) {
SDValue Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl,
HiReg, NVT, InFlag);
InFlag = Result.getValue(2);
ReplaceUses(SDValue(Node, 1), Result);
LLVM_DEBUG(dbgs() << "=> "; Result.getNode()->dump(CurDAG);
dbgs() << '\n');
}
CurDAG->RemoveDeadNode(Node);
return;
}
case X86ISD::CMP: {
SDValue N0 = Node->getOperand(0);
SDValue N1 = Node->getOperand(1);
// Optimizations for TEST compares.
if (!isNullConstant(N1))
break;
// Save the original VT of the compare.
MVT CmpVT = N0.getSimpleValueType();
// If we are comparing (and (shr X, C, Mask) with 0, emit a BEXTR followed
// by a test instruction. The test should be removed later by
// analyzeCompare if we are using only the zero flag.
// TODO: Should we check the users and use the BEXTR flags directly?
if (N0.getOpcode() == ISD::AND && N0.hasOneUse()) {
if (MachineSDNode *NewNode = matchBEXTRFromAndImm(N0.getNode())) {
unsigned TestOpc = CmpVT == MVT::i64 ? X86::TEST64rr
: X86::TEST32rr;
SDValue BEXTR = SDValue(NewNode, 0);
NewNode = CurDAG->getMachineNode(TestOpc, dl, MVT::i32, BEXTR, BEXTR);
ReplaceUses(SDValue(Node, 0), SDValue(NewNode, 0));
CurDAG->RemoveDeadNode(Node);
return;
}
}
// We can peek through truncates, but we need to be careful below.
if (N0.getOpcode() == ISD::TRUNCATE && N0.hasOneUse())
N0 = N0.getOperand(0);
// Look for (X86cmp (and $op, $imm), 0) and see if we can convert it to
// use a smaller encoding.
// Look past the truncate if CMP is the only use of it.
if (N0.getOpcode() == ISD::AND &&
N0.getNode()->hasOneUse() &&
N0.getValueType() != MVT::i8) {
ConstantSDNode *C = dyn_cast<ConstantSDNode>(N0.getOperand(1));
if (!C) break;
uint64_t Mask = C->getZExtValue();
// Check if we can replace AND+IMM64 with a shift. This is possible for
// masks/ like 0xFF000000 or 0x00FFFFFF and if we care only about the zero
// flag.
if (CmpVT == MVT::i64 && !isInt<32>(Mask) &&
onlyUsesZeroFlag(SDValue(Node, 0))) {
if (isMask_64(~Mask)) {
unsigned TrailingZeros = countTrailingZeros(Mask);
SDValue Imm = CurDAG->getTargetConstant(TrailingZeros, dl, MVT::i64);
SDValue Shift =
SDValue(CurDAG->getMachineNode(X86::SHR64ri, dl, MVT::i64, MVT::i32,
N0.getOperand(0), Imm), 0);
MachineSDNode *Test = CurDAG->getMachineNode(X86::TEST64rr, dl,
MVT::i32, Shift, Shift);
ReplaceNode(Node, Test);
return;
}
if (isMask_64(Mask)) {
unsigned LeadingZeros = countLeadingZeros(Mask);
SDValue Imm = CurDAG->getTargetConstant(LeadingZeros, dl, MVT::i64);
SDValue Shift =
SDValue(CurDAG->getMachineNode(X86::SHL64ri, dl, MVT::i64, MVT::i32,
N0.getOperand(0), Imm), 0);
MachineSDNode *Test = CurDAG->getMachineNode(X86::TEST64rr, dl,
MVT::i32, Shift, Shift);
ReplaceNode(Node, Test);
return;
}
}
MVT VT;
int SubRegOp;
unsigned ROpc, MOpc;
// For each of these checks we need to be careful if the sign flag is
// being used. It is only safe to use the sign flag in two conditions,
// either the sign bit in the shrunken mask is zero or the final test
// size is equal to the original compare size.
if (isUInt<8>(Mask) &&
(!(Mask & 0x80) || CmpVT == MVT::i8 ||
hasNoSignFlagUses(SDValue(Node, 0)))) {
// For example, convert "testl %eax, $8" to "testb %al, $8"
VT = MVT::i8;
SubRegOp = X86::sub_8bit;
ROpc = X86::TEST8ri;
MOpc = X86::TEST8mi;
} else if (OptForMinSize && isUInt<16>(Mask) &&
(!(Mask & 0x8000) || CmpVT == MVT::i16 ||
hasNoSignFlagUses(SDValue(Node, 0)))) {
// For example, "testl %eax, $32776" to "testw %ax, $32776".
// NOTE: We only want to form TESTW instructions if optimizing for
// min size. Otherwise we only save one byte and possibly get a length
// changing prefix penalty in the decoders.
VT = MVT::i16;
SubRegOp = X86::sub_16bit;
ROpc = X86::TEST16ri;
MOpc = X86::TEST16mi;
} else if (isUInt<32>(Mask) && N0.getValueType() != MVT::i16 &&
((!(Mask & 0x80000000) &&
// Without minsize 16-bit Cmps can get here so we need to
// be sure we calculate the correct sign flag if needed.
(CmpVT != MVT::i16 || !(Mask & 0x8000))) ||
CmpVT == MVT::i32 ||
hasNoSignFlagUses(SDValue(Node, 0)))) {
// For example, "testq %rax, $268468232" to "testl %eax, $268468232".
// NOTE: We only want to run that transform if N0 is 32 or 64 bits.
// Otherwize, we find ourselves in a position where we have to do
// promotion. If previous passes did not promote the and, we assume
// they had a good reason not to and do not promote here.
VT = MVT::i32;
SubRegOp = X86::sub_32bit;
ROpc = X86::TEST32ri;
MOpc = X86::TEST32mi;
} else {
// No eligible transformation was found.
break;
}
SDValue Imm = CurDAG->getTargetConstant(Mask, dl, VT);
SDValue Reg = N0.getOperand(0);
// Emit a testl or testw.
MachineSDNode *NewNode;
SDValue Tmp0, Tmp1, Tmp2, Tmp3, Tmp4;
if (tryFoldLoad(Node, N0.getNode(), Reg, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4)) {
SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, Imm,
Reg.getOperand(0) };
NewNode = CurDAG->getMachineNode(MOpc, dl, MVT::i32, MVT::Other, Ops);
// Update the chain.
ReplaceUses(Reg.getValue(1), SDValue(NewNode, 1));
// Record the mem-refs
CurDAG->setNodeMemRefs(NewNode,
{cast<LoadSDNode>(Reg)->getMemOperand()});
} else {
// Extract the subregister if necessary.
if (N0.getValueType() != VT)
Reg = CurDAG->getTargetExtractSubreg(SubRegOp, dl, VT, Reg);
NewNode = CurDAG->getMachineNode(ROpc, dl, MVT::i32, Reg, Imm);
}
// Replace CMP with TEST.
ReplaceNode(Node, NewNode);
return;
}
break;
}
case X86ISD::PCMPISTR: {
if (!Subtarget->hasSSE42())
break;
bool NeedIndex = !SDValue(Node, 0).use_empty();
bool NeedMask = !SDValue(Node, 1).use_empty();
// We can't fold a load if we are going to make two instructions.
bool MayFoldLoad = !NeedIndex || !NeedMask;
MachineSDNode *CNode;
if (NeedMask) {
unsigned ROpc = Subtarget->hasAVX() ? X86::VPCMPISTRMrr : X86::PCMPISTRMrr;
unsigned MOpc = Subtarget->hasAVX() ? X86::VPCMPISTRMrm : X86::PCMPISTRMrm;
CNode = emitPCMPISTR(ROpc, MOpc, MayFoldLoad, dl, MVT::v16i8, Node);
ReplaceUses(SDValue(Node, 1), SDValue(CNode, 0));
}
if (NeedIndex || !NeedMask) {
unsigned ROpc = Subtarget->hasAVX() ? X86::VPCMPISTRIrr : X86::PCMPISTRIrr;
unsigned MOpc = Subtarget->hasAVX() ? X86::VPCMPISTRIrm : X86::PCMPISTRIrm;
CNode = emitPCMPISTR(ROpc, MOpc, MayFoldLoad, dl, MVT::i32, Node);
ReplaceUses(SDValue(Node, 0), SDValue(CNode, 0));
}
// Connect the flag usage to the last instruction created.
ReplaceUses(SDValue(Node, 2), SDValue(CNode, 1));
CurDAG->RemoveDeadNode(Node);
return;
}
case X86ISD::PCMPESTR: {
if (!Subtarget->hasSSE42())
break;
// Copy the two implicit register inputs.
SDValue InFlag = CurDAG->getCopyToReg(CurDAG->getEntryNode(), dl, X86::EAX,
Node->getOperand(1),
SDValue()).getValue(1);
InFlag = CurDAG->getCopyToReg(CurDAG->getEntryNode(), dl, X86::EDX,
Node->getOperand(3), InFlag).getValue(1);
bool NeedIndex = !SDValue(Node, 0).use_empty();
bool NeedMask = !SDValue(Node, 1).use_empty();
// We can't fold a load if we are going to make two instructions.
bool MayFoldLoad = !NeedIndex || !NeedMask;
MachineSDNode *CNode;
if (NeedMask) {
unsigned ROpc = Subtarget->hasAVX() ? X86::VPCMPESTRMrr : X86::PCMPESTRMrr;
unsigned MOpc = Subtarget->hasAVX() ? X86::VPCMPESTRMrm : X86::PCMPESTRMrm;
CNode = emitPCMPESTR(ROpc, MOpc, MayFoldLoad, dl, MVT::v16i8, Node,
InFlag);
ReplaceUses(SDValue(Node, 1), SDValue(CNode, 0));
}
if (NeedIndex || !NeedMask) {
unsigned ROpc = Subtarget->hasAVX() ? X86::VPCMPESTRIrr : X86::PCMPESTRIrr;
unsigned MOpc = Subtarget->hasAVX() ? X86::VPCMPESTRIrm : X86::PCMPESTRIrm;
CNode = emitPCMPESTR(ROpc, MOpc, MayFoldLoad, dl, MVT::i32, Node, InFlag);
ReplaceUses(SDValue(Node, 0), SDValue(CNode, 0));
}
// Connect the flag usage to the last instruction created.
ReplaceUses(SDValue(Node, 2), SDValue(CNode, 1));
CurDAG->RemoveDeadNode(Node);
return;
}
case ISD::SETCC: {
if (NVT.isVector() && tryVPTESTM(Node, SDValue(Node, 0), SDValue()))
return;
break;
}
case ISD::STORE:
if (foldLoadStoreIntoMemOperand(Node))
return;
break;
case ISD::FCEIL:
case ISD::FFLOOR:
case ISD::FTRUNC:
case ISD::FNEARBYINT:
case ISD::FRINT: {
// Replace fp rounding with their X86 specific equivalent so we don't
// need 2 sets of patterns.
// FIXME: This can only happen when the nodes started as STRICT_* and have
// been mutated into their non-STRICT equivalents. Eventually this
// mutation will be removed and we should switch the STRICT_ nodes to a
// strict version of RNDSCALE in PreProcessISelDAG.
unsigned Imm;
switch (Node->getOpcode()) {
default: llvm_unreachable("Unexpected opcode!");
case ISD::FCEIL: Imm = 0xA; break;
case ISD::FFLOOR: Imm = 0x9; break;
case ISD::FTRUNC: Imm = 0xB; break;
case ISD::FNEARBYINT: Imm = 0xC; break;
case ISD::FRINT: Imm = 0x4; break;
}
SDLoc dl(Node);
SDValue Res = CurDAG->getNode(X86ISD::VRNDSCALE, dl,
Node->getValueType(0),
Node->getOperand(0),
CurDAG->getConstant(Imm, dl, MVT::i8));
ReplaceNode(Node, Res.getNode());
SelectCode(Res.getNode());
return;
}
}
SelectCode(Node);
}
bool X86DAGToDAGISel::
SelectInlineAsmMemoryOperand(const SDValue &Op, unsigned ConstraintID,
std::vector<SDValue> &OutOps) {
SDValue Op0, Op1, Op2, Op3, Op4;
switch (ConstraintID) {
default:
llvm_unreachable("Unexpected asm memory constraint");
case InlineAsm::Constraint_i:
// FIXME: It seems strange that 'i' is needed here since it's supposed to
// be an immediate and not a memory constraint.
LLVM_FALLTHROUGH;
case InlineAsm::Constraint_o: // offsetable ??
case InlineAsm::Constraint_v: // not offsetable ??
case InlineAsm::Constraint_m: // memory
case InlineAsm::Constraint_X:
if (!selectAddr(nullptr, Op, Op0, Op1, Op2, Op3, Op4))
return true;
break;
}
OutOps.push_back(Op0);
OutOps.push_back(Op1);
OutOps.push_back(Op2);
OutOps.push_back(Op3);
OutOps.push_back(Op4);
return false;
}
/// This pass converts a legalized DAG into a X86-specific DAG,
/// ready for instruction scheduling.
FunctionPass *llvm::createX86ISelDag(X86TargetMachine &TM,
CodeGenOpt::Level OptLevel) {
return new X86DAGToDAGISel(TM, OptLevel);
}
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