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llvm-6502/lib/CodeGen/SelectionDAG/TargetLowering.cpp
Dan Gohman 707e018423 Drop ISD::MEMSET, ISD::MEMMOVE, and ISD::MEMCPY, which are not Legal 
on any current target and aren't optimized in DAGCombiner. Instead
of using intermediate nodes, expand the operations, choosing between
simple loads/stores, target-specific code, and library calls,
immediately.

Previously, the code to emit optimized code for these operations
was only used at initial SelectionDAG construction time; now it is
used at all times. This fixes some cases where rep;movs was being
used for small copies where simple loads/stores would be better.

This also cleans up code that checks for alignments less than 4;
let the targets make that decision instead of doing it in
target-independent code. This allows x86 to use rep;movs in
low-alignment cases.

Also, this fixes a bug that resulted in the use of rep;stos for
memsets of 0 with non-constant memory size when the alignment was
at least 4. It's better to use the library in this case, which
can be significantly faster when the size is large.

This also preserves more SourceValue information when memory
intrinsics are lowered into simple loads/stores.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49572 91177308-0d34-0410-b5e6-96231b3b80d8
2008-04-12 04:36:06 +00:00

1964 lines
78 KiB
C++
Raw Blame History

//===-- 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/GlobalVariable.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() {}
/// 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.
// for XOR, we prefer to force bits to 1 if they will make a -1.
// if we can't force bits, try to shrink constant
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
APInt Expanded = C->getAPIntValue() | (~NewMask);
// if we can expand it to have all bits set, do it
if (Expanded.isAllOnesValue()) {
if (Expanded != C->getAPIntValue()) {
MVT::ValueType VT = Op.getValueType();
SDOperand New = TLO.DAG.getNode(Op.getOpcode(), VT, Op.getOperand(0),
TLO.DAG.getConstant(Expanded, VT));
return TLO.CombineTo(Op, New);
}
// if it already has all the bits set, nothing to change
// but don't shrink either!
} else 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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