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llvm-mirror/lib/CodeGen/SelectionDAG/TargetLowering.cpp
Dan Gohman 486f664806 More APInt-ification. 
llvm-svn: 48344
2008-03-13 22:13:53 +00:00

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//===-- TargetLowering.cpp - Implement the TargetLowering class -----------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This implements the TargetLowering class.
//
//===----------------------------------------------------------------------===//
#include "llvm/Target/TargetAsmInfo.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetSubtarget.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/CallingConv.h"
#include "llvm/DerivedTypes.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/MathExtras.h"
using namespace llvm;
/// InitLibcallNames - Set default libcall names.
///
static void InitLibcallNames(const char **Names) {
Names[RTLIB::SHL_I32] = "__ashlsi3";
Names[RTLIB::SHL_I64] = "__ashldi3";
Names[RTLIB::SRL_I32] = "__lshrsi3";
Names[RTLIB::SRL_I64] = "__lshrdi3";
Names[RTLIB::SRA_I32] = "__ashrsi3";
Names[RTLIB::SRA_I64] = "__ashrdi3";
Names[RTLIB::MUL_I32] = "__mulsi3";
Names[RTLIB::MUL_I64] = "__muldi3";
Names[RTLIB::SDIV_I32] = "__divsi3";
Names[RTLIB::SDIV_I64] = "__divdi3";
Names[RTLIB::UDIV_I32] = "__udivsi3";
Names[RTLIB::UDIV_I64] = "__udivdi3";
Names[RTLIB::SREM_I32] = "__modsi3";
Names[RTLIB::SREM_I64] = "__moddi3";
Names[RTLIB::UREM_I32] = "__umodsi3";
Names[RTLIB::UREM_I64] = "__umoddi3";
Names[RTLIB::NEG_I32] = "__negsi2";
Names[RTLIB::NEG_I64] = "__negdi2";
Names[RTLIB::ADD_F32] = "__addsf3";
Names[RTLIB::ADD_F64] = "__adddf3";
Names[RTLIB::ADD_F80] = "__addxf3";
Names[RTLIB::ADD_PPCF128] = "__gcc_qadd";
Names[RTLIB::SUB_F32] = "__subsf3";
Names[RTLIB::SUB_F64] = "__subdf3";
Names[RTLIB::SUB_F80] = "__subxf3";
Names[RTLIB::SUB_PPCF128] = "__gcc_qsub";
Names[RTLIB::MUL_F32] = "__mulsf3";
Names[RTLIB::MUL_F64] = "__muldf3";
Names[RTLIB::MUL_F80] = "__mulxf3";
Names[RTLIB::MUL_PPCF128] = "__gcc_qmul";
Names[RTLIB::DIV_F32] = "__divsf3";
Names[RTLIB::DIV_F64] = "__divdf3";
Names[RTLIB::DIV_F80] = "__divxf3";
Names[RTLIB::DIV_PPCF128] = "__gcc_qdiv";
Names[RTLIB::REM_F32] = "fmodf";
Names[RTLIB::REM_F64] = "fmod";
Names[RTLIB::REM_F80] = "fmodl";
Names[RTLIB::REM_PPCF128] = "fmodl";
Names[RTLIB::POWI_F32] = "__powisf2";
Names[RTLIB::POWI_F64] = "__powidf2";
Names[RTLIB::POWI_F80] = "__powixf2";
Names[RTLIB::POWI_PPCF128] = "__powitf2";
Names[RTLIB::SQRT_F32] = "sqrtf";
Names[RTLIB::SQRT_F64] = "sqrt";
Names[RTLIB::SQRT_F80] = "sqrtl";
Names[RTLIB::SQRT_PPCF128] = "sqrtl";
Names[RTLIB::SIN_F32] = "sinf";
Names[RTLIB::SIN_F64] = "sin";
Names[RTLIB::SIN_F80] = "sinl";
Names[RTLIB::SIN_PPCF128] = "sinl";
Names[RTLIB::COS_F32] = "cosf";
Names[RTLIB::COS_F64] = "cos";
Names[RTLIB::COS_F80] = "cosl";
Names[RTLIB::COS_PPCF128] = "cosl";
Names[RTLIB::POW_F32] = "powf";
Names[RTLIB::POW_F64] = "pow";
Names[RTLIB::POW_F80] = "powl";
Names[RTLIB::POW_PPCF128] = "powl";
Names[RTLIB::FPEXT_F32_F64] = "__extendsfdf2";
Names[RTLIB::FPROUND_F64_F32] = "__truncdfsf2";
Names[RTLIB::FPTOSINT_F32_I32] = "__fixsfsi";
Names[RTLIB::FPTOSINT_F32_I64] = "__fixsfdi";
Names[RTLIB::FPTOSINT_F32_I128] = "__fixsfti";
Names[RTLIB::FPTOSINT_F64_I32] = "__fixdfsi";
Names[RTLIB::FPTOSINT_F64_I64] = "__fixdfdi";
Names[RTLIB::FPTOSINT_F64_I128] = "__fixdfti";
Names[RTLIB::FPTOSINT_F80_I64] = "__fixxfdi";
Names[RTLIB::FPTOSINT_F80_I128] = "__fixxfti";
Names[RTLIB::FPTOSINT_PPCF128_I64] = "__fixtfdi";
Names[RTLIB::FPTOSINT_PPCF128_I128] = "__fixtfti";
Names[RTLIB::FPTOUINT_F32_I32] = "__fixunssfsi";
Names[RTLIB::FPTOUINT_F32_I64] = "__fixunssfdi";
Names[RTLIB::FPTOUINT_F32_I128] = "__fixunssfti";
Names[RTLIB::FPTOUINT_F64_I32] = "__fixunsdfsi";
Names[RTLIB::FPTOUINT_F64_I64] = "__fixunsdfdi";
Names[RTLIB::FPTOUINT_F64_I128] = "__fixunsdfti";
Names[RTLIB::FPTOUINT_F80_I32] = "__fixunsxfsi";
Names[RTLIB::FPTOUINT_F80_I64] = "__fixunsxfdi";
Names[RTLIB::FPTOUINT_F80_I128] = "__fixunsxfti";
Names[RTLIB::FPTOUINT_PPCF128_I64] = "__fixunstfdi";
Names[RTLIB::FPTOUINT_PPCF128_I128] = "__fixunstfti";
Names[RTLIB::SINTTOFP_I32_F32] = "__floatsisf";
Names[RTLIB::SINTTOFP_I32_F64] = "__floatsidf";
Names[RTLIB::SINTTOFP_I64_F32] = "__floatdisf";
Names[RTLIB::SINTTOFP_I64_F64] = "__floatdidf";
Names[RTLIB::SINTTOFP_I64_F80] = "__floatdixf";
Names[RTLIB::SINTTOFP_I64_PPCF128] = "__floatditf";
Names[RTLIB::SINTTOFP_I128_F32] = "__floattisf";
Names[RTLIB::SINTTOFP_I128_F64] = "__floattidf";
Names[RTLIB::SINTTOFP_I128_F80] = "__floattixf";
Names[RTLIB::SINTTOFP_I128_PPCF128] = "__floattitf";
Names[RTLIB::UINTTOFP_I32_F32] = "__floatunsisf";
Names[RTLIB::UINTTOFP_I32_F64] = "__floatunsidf";
Names[RTLIB::UINTTOFP_I64_F32] = "__floatundisf";
Names[RTLIB::UINTTOFP_I64_F64] = "__floatundidf";
Names[RTLIB::OEQ_F32] = "__eqsf2";
Names[RTLIB::OEQ_F64] = "__eqdf2";
Names[RTLIB::UNE_F32] = "__nesf2";
Names[RTLIB::UNE_F64] = "__nedf2";
Names[RTLIB::OGE_F32] = "__gesf2";
Names[RTLIB::OGE_F64] = "__gedf2";
Names[RTLIB::OLT_F32] = "__ltsf2";
Names[RTLIB::OLT_F64] = "__ltdf2";
Names[RTLIB::OLE_F32] = "__lesf2";
Names[RTLIB::OLE_F64] = "__ledf2";
Names[RTLIB::OGT_F32] = "__gtsf2";
Names[RTLIB::OGT_F64] = "__gtdf2";
Names[RTLIB::UO_F32] = "__unordsf2";
Names[RTLIB::UO_F64] = "__unorddf2";
Names[RTLIB::O_F32] = "__unordsf2";
Names[RTLIB::O_F64] = "__unorddf2";
}
/// InitCmpLibcallCCs - Set default comparison libcall CC.
///
static void InitCmpLibcallCCs(ISD::CondCode *CCs) {
memset(CCs, ISD::SETCC_INVALID, sizeof(ISD::CondCode)*RTLIB::UNKNOWN_LIBCALL);
CCs[RTLIB::OEQ_F32] = ISD::SETEQ;
CCs[RTLIB::OEQ_F64] = ISD::SETEQ;
CCs[RTLIB::UNE_F32] = ISD::SETNE;
CCs[RTLIB::UNE_F64] = ISD::SETNE;
CCs[RTLIB::OGE_F32] = ISD::SETGE;
CCs[RTLIB::OGE_F64] = ISD::SETGE;
CCs[RTLIB::OLT_F32] = ISD::SETLT;
CCs[RTLIB::OLT_F64] = ISD::SETLT;
CCs[RTLIB::OLE_F32] = ISD::SETLE;
CCs[RTLIB::OLE_F64] = ISD::SETLE;
CCs[RTLIB::OGT_F32] = ISD::SETGT;
CCs[RTLIB::OGT_F64] = ISD::SETGT;
CCs[RTLIB::UO_F32] = ISD::SETNE;
CCs[RTLIB::UO_F64] = ISD::SETNE;
CCs[RTLIB::O_F32] = ISD::SETEQ;
CCs[RTLIB::O_F64] = ISD::SETEQ;
}
TargetLowering::TargetLowering(TargetMachine &tm)
: TM(tm), TD(TM.getTargetData()) {
assert(ISD::BUILTIN_OP_END <= 156 &&
"Fixed size array in TargetLowering is not large enough!");
// All operations default to being supported.
memset(OpActions, 0, sizeof(OpActions));
memset(LoadXActions, 0, sizeof(LoadXActions));
memset(TruncStoreActions, 0, sizeof(TruncStoreActions));
memset(IndexedModeActions, 0, sizeof(IndexedModeActions));
memset(ConvertActions, 0, sizeof(ConvertActions));
// Set default actions for various operations.
for (unsigned VT = 0; VT != (unsigned)MVT::LAST_VALUETYPE; ++VT) {
// Default all indexed load / store to expand.
for (unsigned IM = (unsigned)ISD::PRE_INC;
IM != (unsigned)ISD::LAST_INDEXED_MODE; ++IM) {
setIndexedLoadAction(IM, (MVT::ValueType)VT, Expand);
setIndexedStoreAction(IM, (MVT::ValueType)VT, Expand);
}
// These operations default to expand.
setOperationAction(ISD::FGETSIGN, (MVT::ValueType)VT, Expand);
}
// Most targets ignore the @llvm.prefetch intrinsic.
setOperationAction(ISD::PREFETCH, MVT::Other, Expand);
// ConstantFP nodes default to expand. Targets can either change this to
// Legal, in which case all fp constants are legal, or use addLegalFPImmediate
// to optimize expansions for certain constants.
setOperationAction(ISD::ConstantFP, MVT::f32, Expand);
setOperationAction(ISD::ConstantFP, MVT::f64, Expand);
setOperationAction(ISD::ConstantFP, MVT::f80, Expand);
// Default ISD::TRAP to expand (which turns it into abort).
setOperationAction(ISD::TRAP, MVT::Other, Expand);
IsLittleEndian = TD->isLittleEndian();
UsesGlobalOffsetTable = false;
ShiftAmountTy = PointerTy = getValueType(TD->getIntPtrType());
ShiftAmtHandling = Undefined;
memset(RegClassForVT, 0,MVT::LAST_VALUETYPE*sizeof(TargetRegisterClass*));
memset(TargetDAGCombineArray, 0, array_lengthof(TargetDAGCombineArray));
maxStoresPerMemset = maxStoresPerMemcpy = maxStoresPerMemmove = 8;
allowUnalignedMemoryAccesses = false;
UseUnderscoreSetJmp = false;
UseUnderscoreLongJmp = false;
SelectIsExpensive = false;
IntDivIsCheap = false;
Pow2DivIsCheap = false;
StackPointerRegisterToSaveRestore = 0;
ExceptionPointerRegister = 0;
ExceptionSelectorRegister = 0;
SetCCResultContents = UndefinedSetCCResult;
SchedPreferenceInfo = SchedulingForLatency;
JumpBufSize = 0;
JumpBufAlignment = 0;
IfCvtBlockSizeLimit = 2;
IfCvtDupBlockSizeLimit = 0;
PrefLoopAlignment = 0;
InitLibcallNames(LibcallRoutineNames);
InitCmpLibcallCCs(CmpLibcallCCs);
// Tell Legalize whether the assembler supports DEBUG_LOC.
if (!TM.getTargetAsmInfo()->hasDotLocAndDotFile())
setOperationAction(ISD::DEBUG_LOC, MVT::Other, Expand);
}
TargetLowering::~TargetLowering() {}
SDOperand TargetLowering::LowerMEMCPY(SDOperand Op, SelectionDAG &DAG) {
assert(getSubtarget() && "Subtarget not defined");
SDOperand ChainOp = Op.getOperand(0);
SDOperand DestOp = Op.getOperand(1);
SDOperand SourceOp = Op.getOperand(2);
SDOperand CountOp = Op.getOperand(3);
SDOperand AlignOp = Op.getOperand(4);
SDOperand AlwaysInlineOp = Op.getOperand(5);
bool AlwaysInline = (bool)cast<ConstantSDNode>(AlwaysInlineOp)->getValue();
unsigned Align = (unsigned)cast<ConstantSDNode>(AlignOp)->getValue();
if (Align == 0) Align = 1;
// If size is unknown, call memcpy.
ConstantSDNode *I = dyn_cast<ConstantSDNode>(CountOp);
if (!I) {
assert(!AlwaysInline && "Cannot inline copy of unknown size");
return LowerMEMCPYCall(ChainOp, DestOp, SourceOp, CountOp, DAG);
}
// If not DWORD aligned or if size is more than threshold, then call memcpy.
// The libc version is likely to be faster for the following cases. It can
// use the address value and run time information about the CPU.
// With glibc 2.6.1 on a core 2, coping an array of 100M longs was 30% faster
unsigned Size = I->getValue();
if (AlwaysInline ||
(Size <= getSubtarget()->getMaxInlineSizeThreshold() &&
(Align & 3) == 0))
return LowerMEMCPYInline(ChainOp, DestOp, SourceOp, Size, Align, DAG);
return LowerMEMCPYCall(ChainOp, DestOp, SourceOp, CountOp, DAG);
}
SDOperand TargetLowering::LowerMEMCPYCall(SDOperand Chain,
SDOperand Dest,
SDOperand Source,
SDOperand Count,
SelectionDAG &DAG) {
MVT::ValueType IntPtr = getPointerTy();
TargetLowering::ArgListTy Args;
TargetLowering::ArgListEntry Entry;
Entry.Ty = getTargetData()->getIntPtrType();
Entry.Node = Dest; Args.push_back(Entry);
Entry.Node = Source; Args.push_back(Entry);
Entry.Node = Count; Args.push_back(Entry);
std::pair<SDOperand,SDOperand> CallResult =
LowerCallTo(Chain, Type::VoidTy, false, false, false, CallingConv::C,
false, DAG.getExternalSymbol("memcpy", IntPtr), Args, DAG);
return CallResult.second;
}
/// computeRegisterProperties - Once all of the register classes are added,
/// this allows us to compute derived properties we expose.
void TargetLowering::computeRegisterProperties() {
assert(MVT::LAST_VALUETYPE <= 32 &&
"Too many value types for ValueTypeActions to hold!");
// Everything defaults to needing one register.
for (unsigned i = 0; i != MVT::LAST_VALUETYPE; ++i) {
NumRegistersForVT[i] = 1;
RegisterTypeForVT[i] = TransformToType[i] = i;
}
// ...except isVoid, which doesn't need any registers.
NumRegistersForVT[MVT::isVoid] = 0;
// Find the largest integer register class.
unsigned LargestIntReg = MVT::i128;
for (; RegClassForVT[LargestIntReg] == 0; --LargestIntReg)
assert(LargestIntReg != MVT::i1 && "No integer registers defined!");
// Every integer value type larger than this largest register takes twice as
// many registers to represent as the previous ValueType.
for (MVT::ValueType ExpandedReg = LargestIntReg + 1;
MVT::isInteger(ExpandedReg); ++ExpandedReg) {
NumRegistersForVT[ExpandedReg] = 2*NumRegistersForVT[ExpandedReg-1];
RegisterTypeForVT[ExpandedReg] = LargestIntReg;
TransformToType[ExpandedReg] = ExpandedReg - 1;
ValueTypeActions.setTypeAction(ExpandedReg, Expand);
}
// Inspect all of the ValueType's smaller than the largest integer
// register to see which ones need promotion.
MVT::ValueType LegalIntReg = LargestIntReg;
for (MVT::ValueType IntReg = LargestIntReg - 1;
IntReg >= MVT::i1; --IntReg) {
if (isTypeLegal(IntReg)) {
LegalIntReg = IntReg;
} else {
RegisterTypeForVT[IntReg] = TransformToType[IntReg] = LegalIntReg;
ValueTypeActions.setTypeAction(IntReg, Promote);
}
}
// ppcf128 type is really two f64's.
if (!isTypeLegal(MVT::ppcf128)) {
NumRegistersForVT[MVT::ppcf128] = 2*NumRegistersForVT[MVT::f64];
RegisterTypeForVT[MVT::ppcf128] = MVT::f64;
TransformToType[MVT::ppcf128] = MVT::f64;
ValueTypeActions.setTypeAction(MVT::ppcf128, Expand);
}
// Decide how to handle f64. If the target does not have native f64 support,
// expand it to i64 and we will be generating soft float library calls.
if (!isTypeLegal(MVT::f64)) {
NumRegistersForVT[MVT::f64] = NumRegistersForVT[MVT::i64];
RegisterTypeForVT[MVT::f64] = RegisterTypeForVT[MVT::i64];
TransformToType[MVT::f64] = MVT::i64;
ValueTypeActions.setTypeAction(MVT::f64, Expand);
}
// Decide how to handle f32. If the target does not have native support for
// f32, promote it to f64 if it is legal. Otherwise, expand it to i32.
if (!isTypeLegal(MVT::f32)) {
if (isTypeLegal(MVT::f64)) {
NumRegistersForVT[MVT::f32] = NumRegistersForVT[MVT::f64];
RegisterTypeForVT[MVT::f32] = RegisterTypeForVT[MVT::f64];
TransformToType[MVT::f32] = MVT::f64;
ValueTypeActions.setTypeAction(MVT::f32, Promote);
} else {
NumRegistersForVT[MVT::f32] = NumRegistersForVT[MVT::i32];
RegisterTypeForVT[MVT::f32] = RegisterTypeForVT[MVT::i32];
TransformToType[MVT::f32] = MVT::i32;
ValueTypeActions.setTypeAction(MVT::f32, Expand);
}
}
// Loop over all of the vector value types to see which need transformations.
for (MVT::ValueType i = MVT::FIRST_VECTOR_VALUETYPE;
i <= MVT::LAST_VECTOR_VALUETYPE; ++i) {
if (!isTypeLegal(i)) {
MVT::ValueType IntermediateVT, RegisterVT;
unsigned NumIntermediates;
NumRegistersForVT[i] =
getVectorTypeBreakdown(i,
IntermediateVT, NumIntermediates,
RegisterVT);
RegisterTypeForVT[i] = RegisterVT;
TransformToType[i] = MVT::Other; // this isn't actually used
ValueTypeActions.setTypeAction(i, Expand);
}
}
}
const char *TargetLowering::getTargetNodeName(unsigned Opcode) const {
return NULL;
}
MVT::ValueType
TargetLowering::getSetCCResultType(const SDOperand &) const {
return getValueType(TD->getIntPtrType());
}
/// getVectorTypeBreakdown - Vector types are broken down into some number of
/// legal first class types. For example, MVT::v8f32 maps to 2 MVT::v4f32
/// with Altivec or SSE1, or 8 promoted MVT::f64 values with the X86 FP stack.
/// Similarly, MVT::v2i64 turns into 4 MVT::i32 values with both PPC and X86.
///
/// This method returns the number of registers needed, and the VT for each
/// register. It also returns the VT and quantity of the intermediate values
/// before they are promoted/expanded.
///
unsigned TargetLowering::getVectorTypeBreakdown(MVT::ValueType VT,
MVT::ValueType &IntermediateVT,
unsigned &NumIntermediates,
MVT::ValueType &RegisterVT) const {
// Figure out the right, legal destination reg to copy into.
unsigned NumElts = MVT::getVectorNumElements(VT);
MVT::ValueType EltTy = MVT::getVectorElementType(VT);
unsigned NumVectorRegs = 1;
// FIXME: We don't support non-power-of-2-sized vectors for now. Ideally we
// could break down into LHS/RHS like LegalizeDAG does.
if (!isPowerOf2_32(NumElts)) {
NumVectorRegs = NumElts;
NumElts = 1;
}
// Divide the input until we get to a supported size. This will always
// end with a scalar if the target doesn't support vectors.
while (NumElts > 1 &&
!isTypeLegal(MVT::getVectorType(EltTy, NumElts))) {
NumElts >>= 1;
NumVectorRegs <<= 1;
}
NumIntermediates = NumVectorRegs;
MVT::ValueType NewVT = MVT::getVectorType(EltTy, NumElts);
if (!isTypeLegal(NewVT))
NewVT = EltTy;
IntermediateVT = NewVT;
MVT::ValueType DestVT = getTypeToTransformTo(NewVT);
RegisterVT = DestVT;
if (DestVT < NewVT) {
// Value is expanded, e.g. i64 -> i16.
return NumVectorRegs*(MVT::getSizeInBits(NewVT)/MVT::getSizeInBits(DestVT));
} else {
// Otherwise, promotion or legal types use the same number of registers as
// the vector decimated to the appropriate level.
return NumVectorRegs;
}
return 1;
}
/// getByValTypeAlignment - Return the desired alignment for ByVal aggregate
/// function arguments in the caller parameter area. This is the actual
/// alignment, not its logarithm.
unsigned TargetLowering::getByValTypeAlignment(const Type *Ty) const {
return TD->getCallFrameTypeAlignment(Ty);
}
SDOperand TargetLowering::getPICJumpTableRelocBase(SDOperand Table,
SelectionDAG &DAG) const {
if (usesGlobalOffsetTable())
return DAG.getNode(ISD::GLOBAL_OFFSET_TABLE, getPointerTy());
return Table;
}
//===----------------------------------------------------------------------===//
// Optimization Methods
//===----------------------------------------------------------------------===//
/// ShrinkDemandedConstant - Check to see if the specified operand of the
/// specified instruction is a constant integer. If so, check to see if there
/// are any bits set in the constant that are not demanded. If so, shrink the
/// constant and return true.
bool TargetLowering::TargetLoweringOpt::ShrinkDemandedConstant(SDOperand Op,
const APInt &Demanded) {
// FIXME: ISD::SELECT, ISD::SELECT_CC
switch(Op.getOpcode()) {
default: break;
case ISD::AND:
case ISD::OR:
case ISD::XOR:
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op.getOperand(1)))
if (C->getAPIntValue().intersects(~Demanded)) {
MVT::ValueType VT = Op.getValueType();
SDOperand New = DAG.getNode(Op.getOpcode(), VT, Op.getOperand(0),
DAG.getConstant(Demanded &
C->getAPIntValue(),
VT));
return CombineTo(Op, New);
}
break;
}
return false;
}
/// SimplifyDemandedBits - Look at Op. At this point, we know that only the
/// DemandedMask bits of the result of Op are ever used downstream. If we can
/// use this information to simplify Op, create a new simplified DAG node and
/// return true, returning the original and new nodes in Old and New. Otherwise,
/// analyze the expression and return a mask of KnownOne and KnownZero bits for
/// the expression (used to simplify the caller). The KnownZero/One bits may
/// only be accurate for those bits in the DemandedMask.
bool TargetLowering::SimplifyDemandedBits(SDOperand Op,
const APInt &DemandedMask,
APInt &KnownZero,
APInt &KnownOne,
TargetLoweringOpt &TLO,
unsigned Depth) const {
unsigned BitWidth = DemandedMask.getBitWidth();
assert(Op.getValueSizeInBits() == BitWidth &&
"Mask size mismatches value type size!");
APInt NewMask = DemandedMask;
// Don't know anything.
KnownZero = KnownOne = APInt(BitWidth, 0);
// Other users may use these bits.
if (!Op.Val->hasOneUse()) {
if (Depth != 0) {
// If not at the root, Just compute the KnownZero/KnownOne bits to
// simplify things downstream.
TLO.DAG.ComputeMaskedBits(Op, DemandedMask, KnownZero, KnownOne, Depth);
return false;
}
// If this is the root being simplified, allow it to have multiple uses,
// just set the NewMask to all bits.
NewMask = APInt::getAllOnesValue(BitWidth);
} else if (DemandedMask == 0) {
// Not demanding any bits from Op.
if (Op.getOpcode() != ISD::UNDEF)
return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::UNDEF, Op.getValueType()));
return false;
} else if (Depth == 6) { // Limit search depth.
return false;
}
APInt KnownZero2, KnownOne2, KnownZeroOut, KnownOneOut;
switch (Op.getOpcode()) {
case ISD::Constant:
// We know all of the bits for a constant!
KnownOne = cast<ConstantSDNode>(Op)->getAPIntValue() & NewMask;
KnownZero = ~KnownOne & NewMask;
return false; // Don't fall through, will infinitely loop.
case ISD::AND:
// If the RHS is a constant, check to see if the LHS would be zero without
// using the bits from the RHS. Below, we use knowledge about the RHS to
// simplify the LHS, here we're using information from the LHS to simplify
// the RHS.
if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
APInt LHSZero, LHSOne;
TLO.DAG.ComputeMaskedBits(Op.getOperand(0), NewMask,
LHSZero, LHSOne, Depth+1);
// If the LHS already has zeros where RHSC does, this and is dead.
if ((LHSZero & NewMask) == (~RHSC->getAPIntValue() & NewMask))
return TLO.CombineTo(Op, Op.getOperand(0));
// If any of the set bits in the RHS are known zero on the LHS, shrink
// the constant.
if (TLO.ShrinkDemandedConstant(Op, ~LHSZero & NewMask))
return true;
}
if (SimplifyDemandedBits(Op.getOperand(1), NewMask, KnownZero,
KnownOne, TLO, Depth+1))
return true;
assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
if (SimplifyDemandedBits(Op.getOperand(0), ~KnownZero & NewMask,
KnownZero2, KnownOne2, TLO, Depth+1))
return true;
assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?");
// If all of the demanded bits are known one on one side, return the other.
// These bits cannot contribute to the result of the 'and'.
if ((NewMask & ~KnownZero2 & KnownOne) == (~KnownZero2 & NewMask))
return TLO.CombineTo(Op, Op.getOperand(0));
if ((NewMask & ~KnownZero & KnownOne2) == (~KnownZero & NewMask))
return TLO.CombineTo(Op, Op.getOperand(1));
// If all of the demanded bits in the inputs are known zeros, return zero.
if ((NewMask & (KnownZero|KnownZero2)) == NewMask)
return TLO.CombineTo(Op, TLO.DAG.getConstant(0, Op.getValueType()));
// If the RHS is a constant, see if we can simplify it.
if (TLO.ShrinkDemandedConstant(Op, ~KnownZero2 & NewMask))
return true;
// Output known-1 bits are only known if set in both the LHS & RHS.
KnownOne &= KnownOne2;
// Output known-0 are known to be clear if zero in either the LHS | RHS.
KnownZero |= KnownZero2;
break;
case ISD::OR:
if (SimplifyDemandedBits(Op.getOperand(1), NewMask, KnownZero,
KnownOne, TLO, Depth+1))
return true;
assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
if (SimplifyDemandedBits(Op.getOperand(0), ~KnownOne & NewMask,
KnownZero2, KnownOne2, TLO, Depth+1))
return true;
assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?");
// If all of the demanded bits are known zero on one side, return the other.
// These bits cannot contribute to the result of the 'or'.
if ((NewMask & ~KnownOne2 & KnownZero) == (~KnownOne2 & NewMask))
return TLO.CombineTo(Op, Op.getOperand(0));
if ((NewMask & ~KnownOne & KnownZero2) == (~KnownOne & NewMask))
return TLO.CombineTo(Op, Op.getOperand(1));
// If all of the potentially set bits on one side are known to be set on
// the other side, just use the 'other' side.
if ((NewMask & ~KnownZero & KnownOne2) == (~KnownZero & NewMask))
return TLO.CombineTo(Op, Op.getOperand(0));
if ((NewMask & ~KnownZero2 & KnownOne) == (~KnownZero2 & NewMask))
return TLO.CombineTo(Op, Op.getOperand(1));
// If the RHS is a constant, see if we can simplify it.
if (TLO.ShrinkDemandedConstant(Op, NewMask))
return true;
// Output known-0 bits are only known if clear in both the LHS & RHS.
KnownZero &= KnownZero2;
// Output known-1 are known to be set if set in either the LHS | RHS.
KnownOne |= KnownOne2;
break;
case ISD::XOR:
if (SimplifyDemandedBits(Op.getOperand(1), NewMask, KnownZero,
KnownOne, TLO, Depth+1))
return true;
assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
if (SimplifyDemandedBits(Op.getOperand(0), NewMask, KnownZero2,
KnownOne2, TLO, Depth+1))
return true;
assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?");
// If all of the demanded bits are known zero on one side, return the other.
// These bits cannot contribute to the result of the 'xor'.
if ((KnownZero & NewMask) == NewMask)
return TLO.CombineTo(Op, Op.getOperand(0));
if ((KnownZero2 & NewMask) == NewMask)
return TLO.CombineTo(Op, Op.getOperand(1));
// If all of the unknown bits are known to be zero on one side or the other
// (but not both) turn this into an *inclusive* or.
// e.g. (A & C1)^(B & C2) -> (A & C1)|(B & C2) iff C1&C2 == 0
if ((NewMask & ~KnownZero & ~KnownZero2) == 0)
return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::OR, Op.getValueType(),
Op.getOperand(0),
Op.getOperand(1)));
// Output known-0 bits are known if clear or set in both the LHS & RHS.
KnownZeroOut = (KnownZero & KnownZero2) | (KnownOne & KnownOne2);
// Output known-1 are known to be set if set in only one of the LHS, RHS.
KnownOneOut = (KnownZero & KnownOne2) | (KnownOne & KnownZero2);
// If all of the demanded bits on one side are known, and all of the set
// bits on that side are also known to be set on the other side, turn this
// into an AND, as we know the bits will be cleared.
// e.g. (X | C1) ^ C2 --> (X | C1) & ~C2 iff (C1&C2) == C2
if ((NewMask & (KnownZero|KnownOne)) == NewMask) { // all known
if ((KnownOne & KnownOne2) == KnownOne) {
MVT::ValueType VT = Op.getValueType();
SDOperand ANDC = TLO.DAG.getConstant(~KnownOne & NewMask, VT);
return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::AND, VT, Op.getOperand(0),
ANDC));
}
}
// If the RHS is a constant, see if we can simplify it.
// FIXME: for XOR, we prefer to force bits to 1 if they will make a -1.
if (TLO.ShrinkDemandedConstant(Op, NewMask))
return true;
KnownZero = KnownZeroOut;
KnownOne = KnownOneOut;
break;
case ISD::SELECT:
if (SimplifyDemandedBits(Op.getOperand(2), NewMask, KnownZero,
KnownOne, TLO, Depth+1))
return true;
if (SimplifyDemandedBits(Op.getOperand(1), NewMask, KnownZero2,
KnownOne2, TLO, Depth+1))
return true;
assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?");
// If the operands are constants, see if we can simplify them.
if (TLO.ShrinkDemandedConstant(Op, NewMask))
return true;
// Only known if known in both the LHS and RHS.
KnownOne &= KnownOne2;
KnownZero &= KnownZero2;
break;
case ISD::SELECT_CC:
if (SimplifyDemandedBits(Op.getOperand(3), NewMask, KnownZero,
KnownOne, TLO, Depth+1))
return true;
if (SimplifyDemandedBits(Op.getOperand(2), NewMask, KnownZero2,
KnownOne2, TLO, Depth+1))
return true;
assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?");
// If the operands are constants, see if we can simplify them.
if (TLO.ShrinkDemandedConstant(Op, NewMask))
return true;
// Only known if known in both the LHS and RHS.
KnownOne &= KnownOne2;
KnownZero &= KnownZero2;
break;
case ISD::SHL:
if (ConstantSDNode *SA = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
unsigned ShAmt = SA->getValue();
SDOperand InOp = Op.getOperand(0);
// If the shift count is an invalid immediate, don't do anything.
if (ShAmt >= BitWidth)
break;
// If this is ((X >>u C1) << ShAmt), see if we can simplify this into a
// single shift. We can do this if the bottom bits (which are shifted
// out) are never demanded.
if (InOp.getOpcode() == ISD::SRL &&
isa<ConstantSDNode>(InOp.getOperand(1))) {
if (ShAmt && (NewMask & APInt::getLowBitsSet(BitWidth, ShAmt)) == 0) {
unsigned C1 = cast<ConstantSDNode>(InOp.getOperand(1))->getValue();
unsigned Opc = ISD::SHL;
int Diff = ShAmt-C1;
if (Diff < 0) {
Diff = -Diff;
Opc = ISD::SRL;
}
SDOperand NewSA =
TLO.DAG.getConstant(Diff, Op.getOperand(1).getValueType());
MVT::ValueType VT = Op.getValueType();
return TLO.CombineTo(Op, TLO.DAG.getNode(Opc, VT,
InOp.getOperand(0), NewSA));
}
}
if (SimplifyDemandedBits(Op.getOperand(0), NewMask.lshr(ShAmt),
KnownZero, KnownOne, TLO, Depth+1))
return true;
KnownZero <<= SA->getValue();
KnownOne <<= SA->getValue();
// low bits known zero.
KnownZero |= APInt::getLowBitsSet(BitWidth, SA->getValue());
}
break;
case ISD::SRL:
if (ConstantSDNode *SA = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
MVT::ValueType VT = Op.getValueType();
unsigned ShAmt = SA->getValue();
unsigned VTSize = MVT::getSizeInBits(VT);
SDOperand InOp = Op.getOperand(0);
// If the shift count is an invalid immediate, don't do anything.
if (ShAmt >= BitWidth)
break;
// If this is ((X << C1) >>u ShAmt), see if we can simplify this into a
// single shift. We can do this if the top bits (which are shifted out)
// are never demanded.
if (InOp.getOpcode() == ISD::SHL &&
isa<ConstantSDNode>(InOp.getOperand(1))) {
if (ShAmt && (NewMask & APInt::getHighBitsSet(VTSize, ShAmt)) == 0) {
unsigned C1 = cast<ConstantSDNode>(InOp.getOperand(1))->getValue();
unsigned Opc = ISD::SRL;
int Diff = ShAmt-C1;
if (Diff < 0) {
Diff = -Diff;
Opc = ISD::SHL;
}
SDOperand NewSA =
TLO.DAG.getConstant(Diff, Op.getOperand(1).getValueType());
return TLO.CombineTo(Op, TLO.DAG.getNode(Opc, VT,
InOp.getOperand(0), NewSA));
}
}
// Compute the new bits that are at the top now.
if (SimplifyDemandedBits(InOp, (NewMask << ShAmt),
KnownZero, KnownOne, TLO, Depth+1))
return true;
assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
KnownZero = KnownZero.lshr(ShAmt);
KnownOne = KnownOne.lshr(ShAmt);
APInt HighBits = APInt::getHighBitsSet(BitWidth, ShAmt);
KnownZero |= HighBits; // High bits known zero.
}
break;
case ISD::SRA:
if (ConstantSDNode *SA = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
MVT::ValueType VT = Op.getValueType();
unsigned ShAmt = SA->getValue();
// If the shift count is an invalid immediate, don't do anything.
if (ShAmt >= BitWidth)
break;
APInt InDemandedMask = (NewMask << ShAmt);
// If any of the demanded bits are produced by the sign extension, we also
// demand the input sign bit.
APInt HighBits = APInt::getHighBitsSet(BitWidth, ShAmt);
if (HighBits.intersects(NewMask))
InDemandedMask |= APInt::getSignBit(MVT::getSizeInBits(VT));
if (SimplifyDemandedBits(Op.getOperand(0), InDemandedMask,
KnownZero, KnownOne, TLO, Depth+1))
return true;
assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
KnownZero = KnownZero.lshr(ShAmt);
KnownOne = KnownOne.lshr(ShAmt);
// Handle the sign bit, adjusted to where it is now in the mask.
APInt SignBit = APInt::getSignBit(BitWidth).lshr(ShAmt);
// If the input sign bit is known to be zero, or if none of the top bits
// are demanded, turn this into an unsigned shift right.
if (KnownZero.intersects(SignBit) || (HighBits & ~NewMask) == HighBits) {
return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::SRL, VT, Op.getOperand(0),
Op.getOperand(1)));
} else if (KnownOne.intersects(SignBit)) { // New bits are known one.
KnownOne |= HighBits;
}
}
break;
case ISD::SIGN_EXTEND_INREG: {
MVT::ValueType EVT = cast<VTSDNode>(Op.getOperand(1))->getVT();
// Sign extension. Compute the demanded bits in the result that are not
// present in the input.
APInt NewBits = APInt::getHighBitsSet(BitWidth,
BitWidth - MVT::getSizeInBits(EVT)) &
NewMask;
// If none of the extended bits are demanded, eliminate the sextinreg.
if (NewBits == 0)
return TLO.CombineTo(Op, Op.getOperand(0));
APInt InSignBit = APInt::getSignBit(MVT::getSizeInBits(EVT));
InSignBit.zext(BitWidth);
APInt InputDemandedBits = APInt::getLowBitsSet(BitWidth,
MVT::getSizeInBits(EVT)) &
NewMask;
// Since the sign extended bits are demanded, we know that the sign
// bit is demanded.
InputDemandedBits |= InSignBit;
if (SimplifyDemandedBits(Op.getOperand(0), InputDemandedBits,
KnownZero, KnownOne, TLO, Depth+1))
return true;
assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
// If the sign bit of the input is known set or clear, then we know the
// top bits of the result.
// If the input sign bit is known zero, convert this into a zero extension.
if (KnownZero.intersects(InSignBit))
return TLO.CombineTo(Op,
TLO.DAG.getZeroExtendInReg(Op.getOperand(0), EVT));
if (KnownOne.intersects(InSignBit)) { // Input sign bit known set
KnownOne |= NewBits;
KnownZero &= ~NewBits;
} else { // Input sign bit unknown
KnownZero &= ~NewBits;
KnownOne &= ~NewBits;
}
break;
}
case ISD::ZERO_EXTEND: {
unsigned OperandBitWidth = Op.getOperand(0).getValueSizeInBits();
APInt InMask = NewMask;
InMask.trunc(OperandBitWidth);
// If none of the top bits are demanded, convert this into an any_extend.
APInt NewBits =
APInt::getHighBitsSet(BitWidth, BitWidth - OperandBitWidth) & NewMask;
if (!NewBits.intersects(NewMask))
return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::ANY_EXTEND,
Op.getValueType(),
Op.getOperand(0)));
if (SimplifyDemandedBits(Op.getOperand(0), InMask,
KnownZero, KnownOne, TLO, Depth+1))
return true;
assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
KnownZero.zext(BitWidth);
KnownOne.zext(BitWidth);
KnownZero |= NewBits;
break;
}
case ISD::SIGN_EXTEND: {
MVT::ValueType InVT = Op.getOperand(0).getValueType();
unsigned InBits = MVT::getSizeInBits(InVT);
APInt InMask = APInt::getLowBitsSet(BitWidth, InBits);
APInt InSignBit = APInt::getBitsSet(BitWidth, InBits - 1, InBits);
APInt NewBits = ~InMask & NewMask;
// If none of the top bits are demanded, convert this into an any_extend.
if (NewBits == 0)
return TLO.CombineTo(Op,TLO.DAG.getNode(ISD::ANY_EXTEND,Op.getValueType(),
Op.getOperand(0)));
// Since some of the sign extended bits are demanded, we know that the sign
// bit is demanded.
APInt InDemandedBits = InMask & NewMask;
InDemandedBits |= InSignBit;
InDemandedBits.trunc(InBits);
if (SimplifyDemandedBits(Op.getOperand(0), InDemandedBits, KnownZero,
KnownOne, TLO, Depth+1))
return true;
KnownZero.zext(BitWidth);
KnownOne.zext(BitWidth);
// If the sign bit is known zero, convert this to a zero extend.
if (KnownZero.intersects(InSignBit))
return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::ZERO_EXTEND,
Op.getValueType(),
Op.getOperand(0)));
// If the sign bit is known one, the top bits match.
if (KnownOne.intersects(InSignBit)) {
KnownOne |= NewBits;
KnownZero &= ~NewBits;
} else { // Otherwise, top bits aren't known.
KnownOne &= ~NewBits;
KnownZero &= ~NewBits;
}
break;
}
case ISD::ANY_EXTEND: {
unsigned OperandBitWidth = Op.getOperand(0).getValueSizeInBits();
APInt InMask = NewMask;
InMask.trunc(OperandBitWidth);
if (SimplifyDemandedBits(Op.getOperand(0), InMask,
KnownZero, KnownOne, TLO, Depth+1))
return true;
assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
KnownZero.zext(BitWidth);
KnownOne.zext(BitWidth);
break;
}
case ISD::TRUNCATE: {
// Simplify the input, using demanded bit information, and compute the known
// zero/one bits live out.
APInt TruncMask = NewMask;
TruncMask.zext(Op.getOperand(0).getValueSizeInBits());
if (SimplifyDemandedBits(Op.getOperand(0), TruncMask,
KnownZero, KnownOne, TLO, Depth+1))
return true;
KnownZero.trunc(BitWidth);
KnownOne.trunc(BitWidth);
// If the input is only used by this truncate, see if we can shrink it based
// on the known demanded bits.
if (Op.getOperand(0).Val->hasOneUse()) {
SDOperand In = Op.getOperand(0);
unsigned InBitWidth = In.getValueSizeInBits();
switch (In.getOpcode()) {
default: break;
case ISD::SRL:
// Shrink SRL by a constant if none of the high bits shifted in are
// demanded.
if (ConstantSDNode *ShAmt = dyn_cast<ConstantSDNode>(In.getOperand(1))){
APInt HighBits = APInt::getHighBitsSet(InBitWidth,
InBitWidth - BitWidth);
HighBits = HighBits.lshr(ShAmt->getValue());
HighBits.trunc(BitWidth);
if (ShAmt->getValue() < BitWidth && !(HighBits & NewMask)) {
// None of the shifted in bits are needed. Add a truncate of the
// shift input, then shift it.
SDOperand NewTrunc = TLO.DAG.getNode(ISD::TRUNCATE,
Op.getValueType(),
In.getOperand(0));
return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::SRL,Op.getValueType(),
NewTrunc, In.getOperand(1)));
}
}
break;
}
}
assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
break;
}
case ISD::AssertZext: {
MVT::ValueType VT = cast<VTSDNode>(Op.getOperand(1))->getVT();
APInt InMask = APInt::getLowBitsSet(BitWidth,
MVT::getSizeInBits(VT));
if (SimplifyDemandedBits(Op.getOperand(0), InMask & NewMask,
KnownZero, KnownOne, TLO, Depth+1))
return true;
assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
KnownZero |= ~InMask & NewMask;
break;
}
case ISD::BIT_CONVERT:
#if 0
// If this is an FP->Int bitcast and if the sign bit is the only thing that
// is demanded, turn this into a FGETSIGN.
if (NewMask == MVT::getIntVTSignBit(Op.getValueType()) &&
MVT::isFloatingPoint(Op.getOperand(0).getValueType()) &&
!MVT::isVector(Op.getOperand(0).getValueType())) {
// Only do this xform if FGETSIGN is valid or if before legalize.
if (!TLO.AfterLegalize ||
isOperationLegal(ISD::FGETSIGN, Op.getValueType())) {
// Make a FGETSIGN + SHL to move the sign bit into the appropriate
// place. We expect the SHL to be eliminated by other optimizations.
SDOperand Sign = TLO.DAG.getNode(ISD::FGETSIGN, Op.getValueType(),
Op.getOperand(0));
unsigned ShVal = MVT::getSizeInBits(Op.getValueType())-1;
SDOperand ShAmt = TLO.DAG.getConstant(ShVal, getShiftAmountTy());
return TLO.CombineTo(Op, TLO.DAG.getNode(ISD::SHL, Op.getValueType(),
Sign, ShAmt));
}
}
#endif
break;
case ISD::ADD:
case ISD::SUB:
case ISD::INTRINSIC_WO_CHAIN:
case ISD::INTRINSIC_W_CHAIN:
case ISD::INTRINSIC_VOID:
case ISD::CTTZ:
case ISD::CTLZ:
case ISD::CTPOP:
case ISD::LOAD:
case ISD::SETCC:
case ISD::FGETSIGN:
// Just use ComputeMaskedBits to compute output bits.
TLO.DAG.ComputeMaskedBits(Op, NewMask, KnownZero, KnownOne, Depth);
break;
}
// If we know the value of all of the demanded bits, return this as a
// constant.
if ((NewMask & (KnownZero|KnownOne)) == NewMask)
return TLO.CombineTo(Op, TLO.DAG.getConstant(KnownOne, Op.getValueType()));
return false;
}
/// computeMaskedBitsForTargetNode - Determine which of the bits specified
/// in Mask are known to be either zero or one and return them in the
/// KnownZero/KnownOne bitsets.
void TargetLowering::computeMaskedBitsForTargetNode(const SDOperand Op,
const APInt &Mask,
APInt &KnownZero,
APInt &KnownOne,
const SelectionDAG &DAG,
unsigned Depth) const {
assert((Op.getOpcode() >= ISD::BUILTIN_OP_END ||
Op.getOpcode() == ISD::INTRINSIC_WO_CHAIN ||
Op.getOpcode() == ISD::INTRINSIC_W_CHAIN ||
Op.getOpcode() == ISD::INTRINSIC_VOID) &&
"Should use MaskedValueIsZero if you don't know whether Op"
" is a target node!");
KnownZero = KnownOne = APInt(Mask.getBitWidth(), 0);
}
/// ComputeNumSignBitsForTargetNode - This method can be implemented by
/// targets that want to expose additional information about sign bits to the
/// DAG Combiner.
unsigned TargetLowering::ComputeNumSignBitsForTargetNode(SDOperand Op,
unsigned Depth) const {
assert((Op.getOpcode() >= ISD::BUILTIN_OP_END ||
Op.getOpcode() == ISD::INTRINSIC_WO_CHAIN ||
Op.getOpcode() == ISD::INTRINSIC_W_CHAIN ||
Op.getOpcode() == ISD::INTRINSIC_VOID) &&
"Should use ComputeNumSignBits if you don't know whether Op"
" is a target node!");
return 1;
}
/// SimplifySetCC - Try to simplify a setcc built with the specified operands
/// and cc. If it is unable to simplify it, return a null SDOperand.
SDOperand
TargetLowering::SimplifySetCC(MVT::ValueType VT, SDOperand N0, SDOperand N1,
ISD::CondCode Cond, bool foldBooleans,
DAGCombinerInfo &DCI) const {
SelectionDAG &DAG = DCI.DAG;
// These setcc operations always fold.
switch (Cond) {
default: break;
case ISD::SETFALSE:
case ISD::SETFALSE2: return DAG.getConstant(0, VT);
case ISD::SETTRUE:
case ISD::SETTRUE2: return DAG.getConstant(1, VT);
}
if (ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.Val)) {
const APInt &C1 = N1C->getAPIntValue();
if (isa<ConstantSDNode>(N0.Val)) {
return DAG.FoldSetCC(VT, N0, N1, Cond);
} else {
// If the LHS is '(srl (ctlz x), 5)', the RHS is 0/1, and this is an
// equality comparison, then we're just comparing whether X itself is
// zero.
if (N0.getOpcode() == ISD::SRL && (C1 == 0 || C1 == 1) &&
N0.getOperand(0).getOpcode() == ISD::CTLZ &&
N0.getOperand(1).getOpcode() == ISD::Constant) {
unsigned ShAmt = cast<ConstantSDNode>(N0.getOperand(1))->getValue();
if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
ShAmt == Log2_32(MVT::getSizeInBits(N0.getValueType()))) {
if ((C1 == 0) == (Cond == ISD::SETEQ)) {
// (srl (ctlz x), 5) == 0 -> X != 0
// (srl (ctlz x), 5) != 1 -> X != 0
Cond = ISD::SETNE;
} else {
// (srl (ctlz x), 5) != 0 -> X == 0
// (srl (ctlz x), 5) == 1 -> X == 0
Cond = ISD::SETEQ;
}
SDOperand Zero = DAG.getConstant(0, N0.getValueType());
return DAG.getSetCC(VT, N0.getOperand(0).getOperand(0),
Zero, Cond);
}
}
// If the LHS is a ZERO_EXTEND, perform the comparison on the input.
if (N0.getOpcode() == ISD::ZERO_EXTEND) {
unsigned InSize = MVT::getSizeInBits(N0.getOperand(0).getValueType());
// If the comparison constant has bits in the upper part, the
// zero-extended value could never match.
if (C1.intersects(APInt::getHighBitsSet(C1.getBitWidth(),
C1.getBitWidth() - InSize))) {
switch (Cond) {
case ISD::SETUGT:
case ISD::SETUGE:
case ISD::SETEQ: return DAG.getConstant(0, VT);
case ISD::SETULT:
case ISD::SETULE:
case ISD::SETNE: return DAG.getConstant(1, VT);
case ISD::SETGT:
case ISD::SETGE:
// True if the sign bit of C1 is set.
return DAG.getConstant(C1.isNegative(), VT);
case ISD::SETLT:
case ISD::SETLE:
// True if the sign bit of C1 isn't set.
return DAG.getConstant(C1.isNonNegative(), VT);
default:
break;
}
}
// Otherwise, we can perform the comparison with the low bits.
switch (Cond) {
case ISD::SETEQ:
case ISD::SETNE:
case ISD::SETUGT:
case ISD::SETUGE:
case ISD::SETULT:
case ISD::SETULE:
return DAG.getSetCC(VT, N0.getOperand(0),
DAG.getConstant(APInt(C1).trunc(InSize),
N0.getOperand(0).getValueType()),
Cond);
default:
break; // todo, be more careful with signed comparisons
}
} else if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG &&
(Cond == ISD::SETEQ || Cond == ISD::SETNE)) {
MVT::ValueType ExtSrcTy = cast<VTSDNode>(N0.getOperand(1))->getVT();
unsigned ExtSrcTyBits = MVT::getSizeInBits(ExtSrcTy);
MVT::ValueType ExtDstTy = N0.getValueType();
unsigned ExtDstTyBits = MVT::getSizeInBits(ExtDstTy);
// If the extended part has any inconsistent bits, it cannot ever
// compare equal. In other words, they have to be all ones or all
// zeros.
APInt ExtBits =
APInt::getHighBitsSet(ExtDstTyBits, ExtDstTyBits - ExtSrcTyBits);
if ((C1 & ExtBits) != 0 && (C1 & ExtBits) != ExtBits)
return DAG.getConstant(Cond == ISD::SETNE, VT);
SDOperand ZextOp;
MVT::ValueType Op0Ty = N0.getOperand(0).getValueType();
if (Op0Ty == ExtSrcTy) {
ZextOp = N0.getOperand(0);
} else {
APInt Imm = APInt::getLowBitsSet(ExtDstTyBits, ExtSrcTyBits);
ZextOp = DAG.getNode(ISD::AND, Op0Ty, N0.getOperand(0),
DAG.getConstant(Imm, Op0Ty));
}
if (!DCI.isCalledByLegalizer())
DCI.AddToWorklist(ZextOp.Val);
// Otherwise, make this a use of a zext.
return DAG.getSetCC(VT, ZextOp,
DAG.getConstant(C1 & APInt::getLowBitsSet(
ExtDstTyBits,
ExtSrcTyBits),
ExtDstTy),
Cond);
} else if ((N1C->isNullValue() || N1C->getAPIntValue() == 1) &&
(Cond == ISD::SETEQ || Cond == ISD::SETNE)) {
// SETCC (SETCC), [0|1], [EQ|NE] -> SETCC
if (N0.getOpcode() == ISD::SETCC) {
bool TrueWhenTrue = (Cond == ISD::SETEQ) ^ (N1C->getValue() != 1);
if (TrueWhenTrue)
return N0;
// Invert the condition.
ISD::CondCode CC = cast<CondCodeSDNode>(N0.getOperand(2))->get();
CC = ISD::getSetCCInverse(CC,
MVT::isInteger(N0.getOperand(0).getValueType()));
return DAG.getSetCC(VT, N0.getOperand(0), N0.getOperand(1), CC);
}
if ((N0.getOpcode() == ISD::XOR ||
(N0.getOpcode() == ISD::AND &&
N0.getOperand(0).getOpcode() == ISD::XOR &&
N0.getOperand(1) == N0.getOperand(0).getOperand(1))) &&
isa<ConstantSDNode>(N0.getOperand(1)) &&
cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue() == 1) {
// If this is (X^1) == 0/1, swap the RHS and eliminate the xor. We
// can only do this if the top bits are known zero.
unsigned BitWidth = N0.getValueSizeInBits();
if (DAG.MaskedValueIsZero(N0,
APInt::getHighBitsSet(BitWidth,
BitWidth-1))) {
// Okay, get the un-inverted input value.
SDOperand Val;
if (N0.getOpcode() == ISD::XOR)
Val = N0.getOperand(0);
else {
assert(N0.getOpcode() == ISD::AND &&
N0.getOperand(0).getOpcode() == ISD::XOR);
// ((X^1)&1)^1 -> X & 1
Val = DAG.getNode(ISD::AND, N0.getValueType(),
N0.getOperand(0).getOperand(0),
N0.getOperand(1));
}
return DAG.getSetCC(VT, Val, N1,
Cond == ISD::SETEQ ? ISD::SETNE : ISD::SETEQ);
}
}
}
APInt MinVal, MaxVal;
unsigned OperandBitSize = MVT::getSizeInBits(N1C->getValueType(0));
if (ISD::isSignedIntSetCC(Cond)) {
MinVal = APInt::getSignedMinValue(OperandBitSize);
MaxVal = APInt::getSignedMaxValue(OperandBitSize);
} else {
MinVal = APInt::getMinValue(OperandBitSize);
MaxVal = APInt::getMaxValue(OperandBitSize);
}
// Canonicalize GE/LE comparisons to use GT/LT comparisons.
if (Cond == ISD::SETGE || Cond == ISD::SETUGE) {
if (C1 == MinVal) return DAG.getConstant(1, VT); // X >= MIN --> true
// X >= C0 --> X > (C0-1)
return DAG.getSetCC(VT, N0, DAG.getConstant(C1-1, N1.getValueType()),
(Cond == ISD::SETGE) ? ISD::SETGT : ISD::SETUGT);
}
if (Cond == ISD::SETLE || Cond == ISD::SETULE) {
if (C1 == MaxVal) return DAG.getConstant(1, VT); // X <= MAX --> true
// X <= C0 --> X < (C0+1)
return DAG.getSetCC(VT, N0, DAG.getConstant(C1+1, N1.getValueType()),
(Cond == ISD::SETLE) ? ISD::SETLT : ISD::SETULT);
}
if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MinVal)
return DAG.getConstant(0, VT); // X < MIN --> false
if ((Cond == ISD::SETGE || Cond == ISD::SETUGE) && C1 == MinVal)
return DAG.getConstant(1, VT); // X >= MIN --> true
if ((Cond == ISD::SETGT || Cond == ISD::SETUGT) && C1 == MaxVal)
return DAG.getConstant(0, VT); // X > MAX --> false
if ((Cond == ISD::SETLE || Cond == ISD::SETULE) && C1 == MaxVal)
return DAG.getConstant(1, VT); // X <= MAX --> true
// Canonicalize setgt X, Min --> setne X, Min
if ((Cond == ISD::SETGT || Cond == ISD::SETUGT) && C1 == MinVal)
return DAG.getSetCC(VT, N0, N1, ISD::SETNE);
// Canonicalize setlt X, Max --> setne X, Max
if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MaxVal)
return DAG.getSetCC(VT, N0, N1, ISD::SETNE);
// If we have setult X, 1, turn it into seteq X, 0
if ((Cond == ISD::SETLT || Cond == ISD::SETULT) && C1 == MinVal+1)
return DAG.getSetCC(VT, N0, DAG.getConstant(MinVal, N0.getValueType()),
ISD::SETEQ);
// If we have setugt X, Max-1, turn it into seteq X, Max
else if ((Cond == ISD::SETGT || Cond == ISD::SETUGT) && C1 == MaxVal-1)
return DAG.getSetCC(VT, N0, DAG.getConstant(MaxVal, N0.getValueType()),
ISD::SETEQ);
// If we have "setcc X, C0", check to see if we can shrink the immediate
// by changing cc.
// SETUGT X, SINTMAX -> SETLT X, 0
if (Cond == ISD::SETUGT && OperandBitSize != 1 &&
C1 == (~0ULL >> (65-OperandBitSize)))
return DAG.getSetCC(VT, N0, DAG.getConstant(0, N1.getValueType()),
ISD::SETLT);
// FIXME: Implement the rest of these.
// Fold bit comparisons when we can.
if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
VT == N0.getValueType() && N0.getOpcode() == ISD::AND)
if (ConstantSDNode *AndRHS =
dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
if (Cond == ISD::SETNE && C1 == 0) {// (X & 8) != 0 --> (X & 8) >> 3
// Perform the xform if the AND RHS is a single bit.
if (isPowerOf2_64(AndRHS->getValue())) {
return DAG.getNode(ISD::SRL, VT, N0,
DAG.getConstant(Log2_64(AndRHS->getValue()),
getShiftAmountTy()));
}
} else if (Cond == ISD::SETEQ && C1 == AndRHS->getValue()) {
// (X & 8) == 8 --> (X & 8) >> 3
// Perform the xform if C1 is a single bit.
if (C1.isPowerOf2()) {
return DAG.getNode(ISD::SRL, VT, N0,
DAG.getConstant(C1.logBase2(), getShiftAmountTy()));
}
}
}
}
} else if (isa<ConstantSDNode>(N0.Val)) {
// Ensure that the constant occurs on the RHS.
return DAG.getSetCC(VT, N1, N0, ISD::getSetCCSwappedOperands(Cond));
}
if (isa<ConstantFPSDNode>(N0.Val)) {
// Constant fold or commute setcc.
SDOperand O = DAG.FoldSetCC(VT, N0, N1, Cond);
if (O.Val) return O;
} else if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(N1.Val)) {
// If the RHS of an FP comparison is a constant, simplify it away in
// some cases.
if (CFP->getValueAPF().isNaN()) {
// If an operand is known to be a nan, we can fold it.
switch (ISD::getUnorderedFlavor(Cond)) {
default: assert(0 && "Unknown flavor!");
case 0: // Known false.
return DAG.getConstant(0, VT);
case 1: // Known true.
return DAG.getConstant(1, VT);
case 2: // Undefined.
return DAG.getNode(ISD::UNDEF, VT);
}
}
// Otherwise, we know the RHS is not a NaN. Simplify the node to drop the
// constant if knowing that the operand is non-nan is enough. We prefer to
// have SETO(x,x) instead of SETO(x, 0.0) because this avoids having to
// materialize 0.0.
if (Cond == ISD::SETO || Cond == ISD::SETUO)
return DAG.getSetCC(VT, N0, N0, Cond);
}
if (N0 == N1) {
// We can always fold X == X for integer setcc's.
if (MVT::isInteger(N0.getValueType()))
return DAG.getConstant(ISD::isTrueWhenEqual(Cond), VT);
unsigned UOF = ISD::getUnorderedFlavor(Cond);
if (UOF == 2) // FP operators that are undefined on NaNs.
return DAG.getConstant(ISD::isTrueWhenEqual(Cond), VT);
if (UOF == unsigned(ISD::isTrueWhenEqual(Cond)))
return DAG.getConstant(UOF, VT);
// Otherwise, we can't fold it. However, we can simplify it to SETUO/SETO
// if it is not already.
ISD::CondCode NewCond = UOF == 0 ? ISD::SETO : ISD::SETUO;
if (NewCond != Cond)
return DAG.getSetCC(VT, N0, N1, NewCond);
}
if ((Cond == ISD::SETEQ || Cond == ISD::SETNE) &&
MVT::isInteger(N0.getValueType())) {
if (N0.getOpcode() == ISD::ADD || N0.getOpcode() == ISD::SUB ||
N0.getOpcode() == ISD::XOR) {
// Simplify (X+Y) == (X+Z) --> Y == Z
if (N0.getOpcode() == N1.getOpcode()) {
if (N0.getOperand(0) == N1.getOperand(0))
return DAG.getSetCC(VT, N0.getOperand(1), N1.getOperand(1), Cond);
if (N0.getOperand(1) == N1.getOperand(1))
return DAG.getSetCC(VT, N0.getOperand(0), N1.getOperand(0), Cond);
if (DAG.isCommutativeBinOp(N0.getOpcode())) {
// If X op Y == Y op X, try other combinations.
if (N0.getOperand(0) == N1.getOperand(1))
return DAG.getSetCC(VT, N0.getOperand(1), N1.getOperand(0), Cond);
if (N0.getOperand(1) == N1.getOperand(0))
return DAG.getSetCC(VT, N0.getOperand(0), N1.getOperand(1), Cond);
}
}
if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(N1)) {
if (ConstantSDNode *LHSR = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
// Turn (X+C1) == C2 --> X == C2-C1
if (N0.getOpcode() == ISD::ADD && N0.Val->hasOneUse()) {
return DAG.getSetCC(VT, N0.getOperand(0),
DAG.getConstant(RHSC->getValue()-LHSR->getValue(),
N0.getValueType()), Cond);
}
// Turn (X^C1) == C2 into X == C1^C2 iff X&~C1 = 0.
if (N0.getOpcode() == ISD::XOR)
// If we know that all of the inverted bits are zero, don't bother
// performing the inversion.
if (DAG.MaskedValueIsZero(N0.getOperand(0), ~LHSR->getAPIntValue()))
return
DAG.getSetCC(VT, N0.getOperand(0),
DAG.getConstant(LHSR->getAPIntValue() ^
RHSC->getAPIntValue(),
N0.getValueType()),
Cond);
}
// Turn (C1-X) == C2 --> X == C1-C2
if (ConstantSDNode *SUBC = dyn_cast<ConstantSDNode>(N0.getOperand(0))) {
if (N0.getOpcode() == ISD::SUB && N0.Val->hasOneUse()) {
return
DAG.getSetCC(VT, N0.getOperand(1),
DAG.getConstant(SUBC->getAPIntValue() -
RHSC->getAPIntValue(),
N0.getValueType()),
Cond);
}
}
}
// Simplify (X+Z) == X --> Z == 0
if (N0.getOperand(0) == N1)
return DAG.getSetCC(VT, N0.getOperand(1),
DAG.getConstant(0, N0.getValueType()), Cond);
if (N0.getOperand(1) == N1) {
if (DAG.isCommutativeBinOp(N0.getOpcode()))
return DAG.getSetCC(VT, N0.getOperand(0),
DAG.getConstant(0, N0.getValueType()), Cond);
else if (N0.Val->hasOneUse()) {
assert(N0.getOpcode() == ISD::SUB && "Unexpected operation!");
// (Z-X) == X --> Z == X<<1
SDOperand SH = DAG.getNode(ISD::SHL, N1.getValueType(),
N1,
DAG.getConstant(1, getShiftAmountTy()));
if (!DCI.isCalledByLegalizer())
DCI.AddToWorklist(SH.Val);
return DAG.getSetCC(VT, N0.getOperand(0), SH, Cond);
}
}
}
if (N1.getOpcode() == ISD::ADD || N1.getOpcode() == ISD::SUB ||
N1.getOpcode() == ISD::XOR) {
// Simplify X == (X+Z) --> Z == 0
if (N1.getOperand(0) == N0) {
return DAG.getSetCC(VT, N1.getOperand(1),
DAG.getConstant(0, N1.getValueType()), Cond);
} else if (N1.getOperand(1) == N0) {
if (DAG.isCommutativeBinOp(N1.getOpcode())) {
return DAG.getSetCC(VT, N1.getOperand(0),
DAG.getConstant(0, N1.getValueType()), Cond);
} else if (N1.Val->hasOneUse()) {
assert(N1.getOpcode() == ISD::SUB && "Unexpected operation!");
// X == (Z-X) --> X<<1 == Z
SDOperand SH = DAG.getNode(ISD::SHL, N1.getValueType(), N0,
DAG.getConstant(1, getShiftAmountTy()));
if (!DCI.isCalledByLegalizer())
DCI.AddToWorklist(SH.Val);
return DAG.getSetCC(VT, SH, N1.getOperand(0), Cond);
}
}
}
}
// Fold away ALL boolean setcc's.
SDOperand Temp;
if (N0.getValueType() == MVT::i1 && foldBooleans) {
switch (Cond) {
default: assert(0 && "Unknown integer setcc!");
case ISD::SETEQ: // X == Y -> (X^Y)^1
Temp = DAG.getNode(ISD::XOR, MVT::i1, N0, N1);
N0 = DAG.getNode(ISD::XOR, MVT::i1, Temp, DAG.getConstant(1, MVT::i1));
if (!DCI.isCalledByLegalizer())
DCI.AddToWorklist(Temp.Val);
break;
case ISD::SETNE: // X != Y --> (X^Y)
N0 = DAG.getNode(ISD::XOR, MVT::i1, N0, N1);
break;
case ISD::SETGT: // X >s Y --> X == 0 & Y == 1 --> X^1 & Y
case ISD::SETULT: // X <u Y --> X == 0 & Y == 1 --> X^1 & Y
Temp = DAG.getNode(ISD::XOR, MVT::i1, N0, DAG.getConstant(1, MVT::i1));
N0 = DAG.getNode(ISD::AND, MVT::i1, N1, Temp);
if (!DCI.isCalledByLegalizer())
DCI.AddToWorklist(Temp.Val);
break;
case ISD::SETLT: // X <s Y --> X == 1 & Y == 0 --> Y^1 & X
case ISD::SETUGT: // X >u Y --> X == 1 & Y == 0 --> Y^1 & X
Temp = DAG.getNode(ISD::XOR, MVT::i1, N1, DAG.getConstant(1, MVT::i1));
N0 = DAG.getNode(ISD::AND, MVT::i1, N0, Temp);
if (!DCI.isCalledByLegalizer())
DCI.AddToWorklist(Temp.Val);
break;
case ISD::SETULE: // X <=u Y --> X == 0 | Y == 1 --> X^1 | Y
case ISD::SETGE: // X >=s Y --> X == 0 | Y == 1 --> X^1 | Y
Temp = DAG.getNode(ISD::XOR, MVT::i1, N0, DAG.getConstant(1, MVT::i1));
N0 = DAG.getNode(ISD::OR, MVT::i1, N1, Temp);
if (!DCI.isCalledByLegalizer())
DCI.AddToWorklist(Temp.Val);
break;
case ISD::SETUGE: // X >=u Y --> X == 1 | Y == 0 --> Y^1 | X
case ISD::SETLE: // X <=s Y --> X == 1 | Y == 0 --> Y^1 | X
Temp = DAG.getNode(ISD::XOR, MVT::i1, N1, DAG.getConstant(1, MVT::i1));
N0 = DAG.getNode(ISD::OR, MVT::i1, N0, Temp);
break;
}
if (VT != MVT::i1) {
if (!DCI.isCalledByLegalizer())
DCI.AddToWorklist(N0.Val);
// FIXME: If running after legalize, we probably can't do this.
N0 = DAG.getNode(ISD::ZERO_EXTEND, VT, N0);
}
return N0;
}
// Could not fold it.
return SDOperand();
}
SDOperand TargetLowering::
PerformDAGCombine(SDNode *N, DAGCombinerInfo &DCI) const {
// Default implementation: no optimization.
return SDOperand();
}
//===----------------------------------------------------------------------===//
// Inline Assembler Implementation Methods
//===----------------------------------------------------------------------===//
TargetLowering::ConstraintType
TargetLowering::getConstraintType(const std::string &Constraint) const {
// FIXME: lots more standard ones to handle.
if (Constraint.size() == 1) {
switch (Constraint[0]) {
default: break;
case 'r': return C_RegisterClass;
case 'm': // memory
case 'o': // offsetable
case 'V': // not offsetable
return C_Memory;
case 'i': // Simple Integer or Relocatable Constant
case 'n': // Simple Integer
case 's': // Relocatable Constant
case 'X': // Allow ANY value.
case 'I': // Target registers.
case 'J':
case 'K':
case 'L':
case 'M':
case 'N':
case 'O':
case 'P':
return C_Other;
}
}
if (Constraint.size() > 1 && Constraint[0] == '{' &&
Constraint[Constraint.size()-1] == '}')
return C_Register;
return C_Unknown;
}
/// LowerXConstraint - try to replace an X constraint, which matches anything,
/// with another that has more specific requirements based on the type of the
/// corresponding operand.
void TargetLowering::lowerXConstraint(MVT::ValueType ConstraintVT,
std::string& s) const {
if (MVT::isInteger(ConstraintVT))
s = "r";
else if (MVT::isFloatingPoint(ConstraintVT))
s = "f"; // works for many targets
else
s = "";
}
/// LowerAsmOperandForConstraint - Lower the specified operand into the Ops
/// vector. If it is invalid, don't add anything to Ops.
void TargetLowering::LowerAsmOperandForConstraint(SDOperand Op,
char ConstraintLetter,
std::vector<SDOperand> &Ops,
SelectionDAG &DAG) {
switch (ConstraintLetter) {
default: break;
case 'X': // Allows any operand; labels (basic block) use this.
if (Op.getOpcode() == ISD::BasicBlock) {
Ops.push_back(Op);
return;
}
// fall through
case 'i': // Simple Integer or Relocatable Constant
case 'n': // Simple Integer
case 's': { // Relocatable Constant
// These operands are interested in values of the form (GV+C), where C may
// be folded in as an offset of GV, or it may be explicitly added. Also, it
// is possible and fine if either GV or C are missing.
ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op);
GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(Op);
// If we have "(add GV, C)", pull out GV/C
if (Op.getOpcode() == ISD::ADD) {
C = dyn_cast<ConstantSDNode>(Op.getOperand(1));
GA = dyn_cast<GlobalAddressSDNode>(Op.getOperand(0));
if (C == 0 || GA == 0) {
C = dyn_cast<ConstantSDNode>(Op.getOperand(0));
GA = dyn_cast<GlobalAddressSDNode>(Op.getOperand(1));
}
if (C == 0 || GA == 0)
C = 0, GA = 0;
}
// If we find a valid operand, map to the TargetXXX version so that the
// value itself doesn't get selected.
if (GA) { // Either &GV or &GV+C
if (ConstraintLetter != 'n') {
int64_t Offs = GA->getOffset();
if (C) Offs += C->getValue();
Ops.push_back(DAG.getTargetGlobalAddress(GA->getGlobal(),
Op.getValueType(), Offs));
return;
}
}
if (C) { // just C, no GV.
// Simple constants are not allowed for 's'.
if (ConstraintLetter != 's') {
Ops.push_back(DAG.getTargetConstant(C->getValue(), Op.getValueType()));
return;
}
}
break;
}
}
}
std::vector<unsigned> TargetLowering::
getRegClassForInlineAsmConstraint(const std::string &Constraint,
MVT::ValueType VT) const {
return std::vector<unsigned>();
}
std::pair<unsigned, const TargetRegisterClass*> TargetLowering::
getRegForInlineAsmConstraint(const std::string &Constraint,
MVT::ValueType VT) const {
if (Constraint[0] != '{')
return std::pair<unsigned, const TargetRegisterClass*>(0, 0);
assert(*(Constraint.end()-1) == '}' && "Not a brace enclosed constraint?");
// Remove the braces from around the name.
std::string RegName(Constraint.begin()+1, Constraint.end()-1);
// Figure out which register class contains this reg.
const TargetRegisterInfo *RI = TM.getRegisterInfo();
for (TargetRegisterInfo::regclass_iterator RCI = RI->regclass_begin(),
E = RI->regclass_end(); RCI != E; ++RCI) {
const TargetRegisterClass *RC = *RCI;
// If none of the the value types for this register class are valid, we
// can't use it. For example, 64-bit reg classes on 32-bit targets.
bool isLegal = false;
for (TargetRegisterClass::vt_iterator I = RC->vt_begin(), E = RC->vt_end();
I != E; ++I) {
if (isTypeLegal(*I)) {
isLegal = true;
break;
}
}
if (!isLegal) continue;
for (TargetRegisterClass::iterator I = RC->begin(), E = RC->end();
I != E; ++I) {
if (StringsEqualNoCase(RegName, RI->get(*I).AsmName))
return std::make_pair(*I, RC);
}
}
return std::pair<unsigned, const TargetRegisterClass*>(0, 0);
}
//===----------------------------------------------------------------------===//
// Loop Strength Reduction hooks
//===----------------------------------------------------------------------===//
/// isLegalAddressingMode - Return true if the addressing mode represented
/// by AM is legal for this target, for a load/store of the specified type.
bool TargetLowering::isLegalAddressingMode(const AddrMode &AM,
const Type *Ty) const {
// The default implementation of this implements a conservative RISCy, r+r and
// r+i addr mode.
// Allows a sign-extended 16-bit immediate field.
if (AM.BaseOffs <= -(1LL << 16) || AM.BaseOffs >= (1LL << 16)-1)
return false;
// No global is ever allowed as a base.
if (AM.BaseGV)
return false;
// Only support r+r,
switch (AM.Scale) {
case 0: // "r+i" or just "i", depending on HasBaseReg.
break;
case 1:
if (AM.HasBaseReg && AM.BaseOffs) // "r+r+i" is not allowed.
return false;
// Otherwise we have r+r or r+i.
break;
case 2:
if (AM.HasBaseReg || AM.BaseOffs) // 2*r+r or 2*r+i is not allowed.
return false;
// Allow 2*r as r+r.
break;
}
return true;
}
// Magic for divide replacement
struct ms {
int64_t m; // magic number
int64_t s; // shift amount
};
struct mu {
uint64_t m; // magic number
int64_t a; // add indicator
int64_t s; // shift amount
};
/// magic - calculate the magic numbers required to codegen an integer sdiv as
/// a sequence of multiply and shifts. Requires that the divisor not be 0, 1,
/// or -1.
static ms magic32(int32_t d) {
int32_t p;
uint32_t ad, anc, delta, q1, r1, q2, r2, t;
const uint32_t two31 = 0x80000000U;
struct ms mag;
ad = abs(d);
t = two31 + ((uint32_t)d >> 31);
anc = t - 1 - t%ad; // absolute value of nc
p = 31; // initialize p
q1 = two31/anc; // initialize q1 = 2p/abs(nc)
r1 = two31 - q1*anc; // initialize r1 = rem(2p,abs(nc))
q2 = two31/ad; // initialize q2 = 2p/abs(d)
r2 = two31 - q2*ad; // initialize r2 = rem(2p,abs(d))
do {
p = p + 1;
q1 = 2*q1; // update q1 = 2p/abs(nc)
r1 = 2*r1; // update r1 = rem(2p/abs(nc))
if (r1 >= anc) { // must be unsigned comparison
q1 = q1 + 1;
r1 = r1 - anc;
}
q2 = 2*q2; // update q2 = 2p/abs(d)
r2 = 2*r2; // update r2 = rem(2p/abs(d))
if (r2 >= ad) { // must be unsigned comparison
q2 = q2 + 1;
r2 = r2 - ad;
}
delta = ad - r2;
} while (q1 < delta || (q1 == delta && r1 == 0));
mag.m = (int32_t)(q2 + 1); // make sure to sign extend
if (d < 0) mag.m = -mag.m; // resulting magic number
mag.s = p - 32; // resulting shift
return mag;
}
/// magicu - calculate the magic numbers required to codegen an integer udiv as
/// a sequence of multiply, add and shifts. Requires that the divisor not be 0.
static mu magicu32(uint32_t d) {
int32_t p;
uint32_t nc, delta, q1, r1, q2, r2;
struct mu magu;
magu.a = 0; // initialize "add" indicator
nc = - 1 - (-d)%d;
p = 31; // initialize p
q1 = 0x80000000/nc; // initialize q1 = 2p/nc
r1 = 0x80000000 - q1*nc; // initialize r1 = rem(2p,nc)
q2 = 0x7FFFFFFF/d; // initialize q2 = (2p-1)/d
r2 = 0x7FFFFFFF - q2*d; // initialize r2 = rem((2p-1),d)
do {
p = p + 1;
if (r1 >= nc - r1 ) {
q1 = 2*q1 + 1; // update q1
r1 = 2*r1 - nc; // update r1
}
else {
q1 = 2*q1; // update q1
r1 = 2*r1; // update r1
}
if (r2 + 1 >= d - r2) {
if (q2 >= 0x7FFFFFFF) magu.a = 1;
q2 = 2*q2 + 1; // update q2
r2 = 2*r2 + 1 - d; // update r2
}
else {
if (q2 >= 0x80000000) magu.a = 1;
q2 = 2*q2; // update q2
r2 = 2*r2 + 1; // update r2
}
delta = d - 1 - r2;
} while (p < 64 && (q1 < delta || (q1 == delta && r1 == 0)));
magu.m = q2 + 1; // resulting magic number
magu.s = p - 32; // resulting shift
return magu;
}
/// magic - calculate the magic numbers required to codegen an integer sdiv as
/// a sequence of multiply and shifts. Requires that the divisor not be 0, 1,
/// or -1.
static ms magic64(int64_t d) {
int64_t p;
uint64_t ad, anc, delta, q1, r1, q2, r2, t;
const uint64_t two63 = 9223372036854775808ULL; // 2^63
struct ms mag;
ad = d >= 0 ? d : -d;
t = two63 + ((uint64_t)d >> 63);
anc = t - 1 - t%ad; // absolute value of nc
p = 63; // initialize p
q1 = two63/anc; // initialize q1 = 2p/abs(nc)
r1 = two63 - q1*anc; // initialize r1 = rem(2p,abs(nc))
q2 = two63/ad; // initialize q2 = 2p/abs(d)
r2 = two63 - q2*ad; // initialize r2 = rem(2p,abs(d))
do {
p = p + 1;
q1 = 2*q1; // update q1 = 2p/abs(nc)
r1 = 2*r1; // update r1 = rem(2p/abs(nc))
if (r1 >= anc) { // must be unsigned comparison
q1 = q1 + 1;
r1 = r1 - anc;
}
q2 = 2*q2; // update q2 = 2p/abs(d)
r2 = 2*r2; // update r2 = rem(2p/abs(d))
if (r2 >= ad) { // must be unsigned comparison
q2 = q2 + 1;
r2 = r2 - ad;
}
delta = ad - r2;
} while (q1 < delta || (q1 == delta && r1 == 0));
mag.m = q2 + 1;
if (d < 0) mag.m = -mag.m; // resulting magic number
mag.s = p - 64; // resulting shift
return mag;
}
/// magicu - calculate the magic numbers required to codegen an integer udiv as
/// a sequence of multiply, add and shifts. Requires that the divisor not be 0.
static mu magicu64(uint64_t d)
{
int64_t p;
uint64_t nc, delta, q1, r1, q2, r2;
struct mu magu;
magu.a = 0; // initialize "add" indicator
nc = - 1 - (-d)%d;
p = 63; // initialize p
q1 = 0x8000000000000000ull/nc; // initialize q1 = 2p/nc
r1 = 0x8000000000000000ull - q1*nc; // initialize r1 = rem(2p,nc)
q2 = 0x7FFFFFFFFFFFFFFFull/d; // initialize q2 = (2p-1)/d
r2 = 0x7FFFFFFFFFFFFFFFull - q2*d; // initialize r2 = rem((2p-1),d)
do {
p = p + 1;
if (r1 >= nc - r1 ) {
q1 = 2*q1 + 1; // update q1
r1 = 2*r1 - nc; // update r1
}
else {
q1 = 2*q1; // update q1
r1 = 2*r1; // update r1
}
if (r2 + 1 >= d - r2) {
if (q2 >= 0x7FFFFFFFFFFFFFFFull) magu.a = 1;
q2 = 2*q2 + 1; // update q2
r2 = 2*r2 + 1 - d; // update r2
}
else {
if (q2 >= 0x8000000000000000ull) magu.a = 1;
q2 = 2*q2; // update q2
r2 = 2*r2 + 1; // update r2
}
delta = d - 1 - r2;
} while (p < 128 && (q1 < delta || (q1 == delta && r1 == 0)));
magu.m = q2 + 1; // resulting magic number
magu.s = p - 64; // resulting shift
return magu;
}
/// BuildSDIVSequence - Given an ISD::SDIV node expressing a divide by constant,
/// return a DAG expression to select that will generate the same value by
/// multiplying by a magic number. See:
/// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html>
SDOperand TargetLowering::BuildSDIV(SDNode *N, SelectionDAG &DAG,
std::vector<SDNode*>* Created) const {
MVT::ValueType VT = N->getValueType(0);
// Check to see if we can do this.
if (!isTypeLegal(VT) || (VT != MVT::i32 && VT != MVT::i64))
return SDOperand(); // BuildSDIV only operates on i32 or i64
int64_t d = cast<ConstantSDNode>(N->getOperand(1))->getSignExtended();
ms magics = (VT == MVT::i32) ? magic32(d) : magic64(d);
// Multiply the numerator (operand 0) by the magic value
SDOperand Q;
if (isOperationLegal(ISD::MULHS, VT))
Q = DAG.getNode(ISD::MULHS, VT, N->getOperand(0),
DAG.getConstant(magics.m, VT));
else if (isOperationLegal(ISD::SMUL_LOHI, VT))
Q = SDOperand(DAG.getNode(ISD::SMUL_LOHI, DAG.getVTList(VT, VT),
N->getOperand(0),
DAG.getConstant(magics.m, VT)).Val, 1);
else
return SDOperand(); // No mulhs or equvialent
// If d > 0 and m < 0, add the numerator
if (d > 0 && magics.m < 0) {
Q = DAG.getNode(ISD::ADD, VT, Q, N->getOperand(0));
if (Created)
Created->push_back(Q.Val);
}
// If d < 0 and m > 0, subtract the numerator.
if (d < 0 && magics.m > 0) {
Q = DAG.getNode(ISD::SUB, VT, Q, N->getOperand(0));
if (Created)
Created->push_back(Q.Val);
}
// Shift right algebraic if shift value is nonzero
if (magics.s > 0) {
Q = DAG.getNode(ISD::SRA, VT, Q,
DAG.getConstant(magics.s, getShiftAmountTy()));
if (Created)
Created->push_back(Q.Val);
}
// Extract the sign bit and add it to the quotient
SDOperand T =
DAG.getNode(ISD::SRL, VT, Q, DAG.getConstant(MVT::getSizeInBits(VT)-1,
getShiftAmountTy()));
if (Created)
Created->push_back(T.Val);
return DAG.getNode(ISD::ADD, VT, Q, T);
}
/// BuildUDIVSequence - Given an ISD::UDIV node expressing a divide by constant,
/// return a DAG expression to select that will generate the same value by
/// multiplying by a magic number. See:
/// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html>
SDOperand TargetLowering::BuildUDIV(SDNode *N, SelectionDAG &DAG,
std::vector<SDNode*>* Created) const {
MVT::ValueType VT = N->getValueType(0);
// Check to see if we can do this.
if (!isTypeLegal(VT) || (VT != MVT::i32 && VT != MVT::i64))
return SDOperand(); // BuildUDIV only operates on i32 or i64
uint64_t d = cast<ConstantSDNode>(N->getOperand(1))->getValue();
mu magics = (VT == MVT::i32) ? magicu32(d) : magicu64(d);
// Multiply the numerator (operand 0) by the magic value
SDOperand Q;
if (isOperationLegal(ISD::MULHU, VT))
Q = DAG.getNode(ISD::MULHU, VT, N->getOperand(0),
DAG.getConstant(magics.m, VT));
else if (isOperationLegal(ISD::UMUL_LOHI, VT))
Q = SDOperand(DAG.getNode(ISD::UMUL_LOHI, DAG.getVTList(VT, VT),
N->getOperand(0),
DAG.getConstant(magics.m, VT)).Val, 1);
else
return SDOperand(); // No mulhu or equvialent
if (Created)
Created->push_back(Q.Val);
if (magics.a == 0) {
return DAG.getNode(ISD::SRL, VT, Q,
DAG.getConstant(magics.s, getShiftAmountTy()));
} else {
SDOperand NPQ = DAG.getNode(ISD::SUB, VT, N->getOperand(0), Q);
if (Created)
Created->push_back(NPQ.Val);
NPQ = DAG.getNode(ISD::SRL, VT, NPQ,
DAG.getConstant(1, getShiftAmountTy()));
if (Created)
Created->push_back(NPQ.Val);
NPQ = DAG.getNode(ISD::ADD, VT, NPQ, Q);
if (Created)
Created->push_back(NPQ.Val);
return DAG.getNode(ISD::SRL, VT, NPQ,
DAG.getConstant(magics.s-1, getShiftAmountTy()));
}
}
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