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Implement the cost of abnormal x86 instruction lowering as a table. 

llvm-svn: 167395
This commit is contained in:
Nadav Rotem 2012-11-05 19:32:46 +00:00
parent f828613945
commit 7411623fd8
5 changed files with 52 additions and 59 deletions
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5
llvm/include/llvm/Target/TargetTransformImpl.h
View File

@ -55,13 +55,16 @@ protected:
const TargetLowering *TLI;
/// Estimate the cost of type-legalization and the legalized type.
std::pair<unsigned, EVT>
std::pair<unsigned, MVT>
getTypeLegalizationCost(LLVMContext &C, EVT Ty) const;
/// Estimate the overhead of scalarizing an instruction. Insert and Extract
/// are set if the result needs to be inserted and/or extracted from vectors.
unsigned getScalarizationOverhead(Type *Ty, bool Insert, bool Extract) const;
// Get the ISD node that corresponds to the Instruction class opcode.
int InstructionOpcodeToISD(unsigned Opcode) const;
public:
explicit VectorTargetTransformImpl(const TargetLowering *TL) : TLI(TL) {}

18
llvm/lib/Target/TargetTransformImpl.cpp
View File

@ -60,7 +60,7 @@ bool ScalarTargetTransformImpl::shouldBuildLookupTables() const {
// Calls used by the vectorizers.
//
//===----------------------------------------------------------------------===//
static int InstructionOpcodeToISD(unsigned Opcode) {
int VectorTargetTransformImpl::InstructionOpcodeToISD(unsigned Opcode) const {
enum InstructionOpcodes {
#define HANDLE_INST(NUM, OPCODE, CLASS) OPCODE = NUM,
#define LAST_OTHER_INST(NUM) InstructionOpcodesCount = NUM
@ -130,7 +130,7 @@ static int InstructionOpcodeToISD(unsigned Opcode) {
llvm_unreachable("Unknown instruction type encountered!");
}
std::pair<unsigned, EVT>
std::pair<unsigned, MVT>
VectorTargetTransformImpl::getTypeLegalizationCost(LLVMContext &C,
EVT Ty) const {
unsigned Cost = 1;
@ -141,7 +141,7 @@ VectorTargetTransformImpl::getTypeLegalizationCost(LLVMContext &C,
TargetLowering::LegalizeKind LK = TLI->getTypeConversion(C, Ty);
if (LK.first == TargetLowering::TypeLegal)
return std::make_pair(Cost, Ty);
return std::make_pair(Cost, Ty.getSimpleVT());
if (LK.first == TargetLowering::TypeSplitVector)
Cost *= 2;
@ -174,7 +174,7 @@ unsigned VectorTargetTransformImpl::getArithmeticInstrCost(unsigned Opcode,
int ISD = InstructionOpcodeToISD(Opcode);
assert(ISD && "Invalid opcode");
std::pair<unsigned, EVT> LT =
std::pair<unsigned, MVT> LT =
getTypeLegalizationCost(Ty->getContext(), TLI->getValueType(Ty));
if (!TLI->isOperationExpand(ISD, LT.second)) {
@ -205,10 +205,10 @@ unsigned VectorTargetTransformImpl::getCastInstrCost(unsigned Opcode, Type *Dst,
int ISD = InstructionOpcodeToISD(Opcode);
assert(ISD && "Invalid opcode");
std::pair<unsigned, EVT> SrcLT =
std::pair<unsigned, MVT> SrcLT =
getTypeLegalizationCost(Src->getContext(), TLI->getValueType(Src));
std::pair<unsigned, EVT> DstLT =
std::pair<unsigned, MVT> DstLT =
getTypeLegalizationCost(Dst->getContext(), TLI->getValueType(Dst));
// Handle scalar conversions.
@ -283,7 +283,7 @@ unsigned VectorTargetTransformImpl::getCmpSelInstrCost(unsigned Opcode,
ISD = ISD::VSELECT;
}
std::pair<unsigned, EVT> LT =
std::pair<unsigned, MVT> LT =
getTypeLegalizationCost(ValTy->getContext(), TLI->getValueType(ValTy));
if (!TLI->isOperationExpand(ISD, LT.second)) {
@ -326,7 +326,7 @@ unsigned
VectorTargetTransformImpl::getMemoryOpCost(unsigned Opcode, Type *Src,
unsigned Alignment,
unsigned AddressSpace) const {
std::pair<unsigned, EVT> LT =
std::pair<unsigned, MVT> LT =
getTypeLegalizationCost(Src->getContext(), TLI->getValueType(Src));
// Assume that all loads of legal types cost 1.
@ -335,7 +335,7 @@ VectorTargetTransformImpl::getMemoryOpCost(unsigned Opcode, Type *Src,
unsigned
VectorTargetTransformImpl::getNumberOfParts(Type *Tp) const {
std::pair<unsigned, EVT> LT =
std::pair<unsigned, MVT> LT =
getTypeLegalizationCost(Tp->getContext(), TLI->getValueType(Tp));
return LT.first;
}

84
llvm/lib/Target/X86/X86ISelLowering.cpp
View File

@ -17505,63 +17505,51 @@ X86TargetLowering::getRegForInlineAsmConstraint(const std::string &Constraint,
return Res;
}
//===----------------------------------------------------------------------===//
//
// X86 cost model.
//
//===----------------------------------------------------------------------===//
struct X86CostTblEntry {
int ISD;
MVT Type;
unsigned Cost;
};
unsigned
X86VectorTargetTransformInfo::getArithmeticInstrCost(unsigned Opcode,
Type *Ty) const {
// Legalize the type.
std::pair<unsigned, MVT> LT =
getTypeLegalizationCost(Ty->getContext(), TLI->getValueType(Ty));
int ISD = InstructionOpcodeToISD(Opcode);
assert(ISD && "Invalid opcode");
const X86Subtarget &ST =
TLI->getTargetMachine().getSubtarget<X86Subtarget>();
// Fix some of the inaccuracies of the target independent estimation.
if (Ty->isVectorTy() && ST.hasSSE41()) {
unsigned NumElem = Ty->getVectorNumElements();
unsigned SizeInBits = Ty->getScalarType()->getScalarSizeInBits();
static const X86CostTblEntry AVX1CostTable[] = {
// We don't have to scalarize unsupported ops. We can issue two half-sized
// operations and we only need to extract the upper YMM half.
// Two ops + 1 extract + 1 insert = 4.
{ ISD::MUL, MVT::v8i32, 4 },
{ ISD::SUB, MVT::v8i32, 4 },
{ ISD::ADD, MVT::v8i32, 4 },
{ ISD::MUL, MVT::v4i64, 4 },
{ ISD::SUB, MVT::v4i64, 4 },
{ ISD::ADD, MVT::v4i64, 4 },
};
bool Is2 = (NumElem == 2);
bool Is4 = (NumElem == 4);
bool Is8 = (NumElem == 8);
bool Is32bits = (SizeInBits == 32);
bool Is64bits = (SizeInBits == 64);
bool HasAvx = ST.hasAVX();
bool HasAvx2 = ST.hasAVX2();
switch (Opcode) {
case Instruction::Add:
case Instruction::Sub:
case Instruction::Mul: {
// Only AVX2 has support for 8-wide integer operations.
if (Is32bits && (Is4 || (Is8 && HasAvx2))) return 1;
if (Is64bits && (Is2 || (Is4 && HasAvx2))) return 1;
// We don't have to completly scalarize unsupported ops. We can
// issue two half-sized operations (with some overhead).
// We don't need to extract the lower part of the YMM to the XMM.
// Extract the upper, two ops, insert the upper = 4.
if (Is32bits && Is8 && HasAvx) return 4;
if (Is64bits && Is4 && HasAvx) return 4;
break;
}
case Instruction::FAdd:
case Instruction::FSub:
case Instruction::FMul: {
// AVX has support for 8-wide float operations.
if (Is32bits && (Is4 || (Is8 && HasAvx))) return 1;
if (Is64bits && (Is2 || (Is4 && HasAvx))) return 1;
break;
}
case Instruction::Shl:
case Instruction::LShr:
case Instruction::AShr:
case Instruction::And:
case Instruction::Or:
case Instruction::Xor: {
// AVX has support for 8-wide integer bitwise operations.
if (Is32bits && (Is4 || (Is8 && HasAvx))) return 1;
if (Is64bits && (Is2 || (Is4 && HasAvx))) return 1;
break;
}
// Look for AVX1 lowering tricks.
if (ST.hasAVX())
for (unsigned int i = 0, e = array_lengthof(AVX1CostTable); i < e; ++i) {
if (AVX1CostTable[i].ISD == ISD && AVX1CostTable[i].Type == LT.second)
return LT.first * AVX1CostTable[i].Cost;
}
}
// Fallback to the default implementation.
return VectorTargetTransformImpl::getArithmeticInstrCost(Opcode, Ty);
}

2
llvm/test/Analysis/CostModel/X86/arith.ll
View File

@ -12,6 +12,8 @@ define i32 @add(i32 %arg) {
%C = add <2 x i64> undef, undef
;CHECK: cost of 4 {{.*}} add
%D = add <4 x i64> undef, undef
;CHECK: cost of 8 {{.*}} add
%E = add <8 x i64> undef, undef
;CHECK: cost of 1 {{.*}} ret
ret i32 undef
}

2
llvm/test/Transforms/LoopVectorize/X86/conversion-cost.ll
View File

@ -25,7 +25,7 @@ define i32 @conversion_cost1(i32 %n, i8* nocapture %A, float* nocapture %B) noun
}
;CHECK: @conversion_cost2
;CHECK: store <8 x float>
;CHECK-NOT: <8 x float>
;CHECK: ret
define i32 @conversion_cost2(i32 %n, i8* nocapture %A, float* nocapture %B) nounwind uwtable ssp {
%1 = icmp sgt i32 %n, 9