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CostModel: improve the cost model for load/store of non power-of-two types such as <3 x float>, which are popular in graphics.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185085 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nadav Rotem 2013-06-27 17:52:04 +00:00
parent 5f72fa5701
commit 16d36a5cd1
2 changed files with 62 additions and 0 deletions
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43
lib/Target/X86/X86TargetTransformInfo.cpp
View File

@ -539,8 +539,51 @@ unsigned X86TTI::getVectorInstrCost(unsigned Opcode, Type *Val,
return TargetTransformInfo::getVectorInstrCost(Opcode, Val, Index);
}
unsigned X86TTI::getScalarizationOverhead(Type *Ty, bool Insert,
bool Extract) const {
assert (Ty->isVectorTy() && "Can only scalarize vectors");
unsigned Cost = 0;
for (int i = 0, e = Ty->getVectorNumElements(); i < e; ++i) {
if (Insert)
Cost += TopTTI->getVectorInstrCost(Instruction::InsertElement, Ty, i);
if (Extract)
Cost += TopTTI->getVectorInstrCost(Instruction::ExtractElement, Ty, i);
}
return Cost;
}
unsigned X86TTI::getMemoryOpCost(unsigned Opcode, Type *Src, unsigned Alignment,
unsigned AddressSpace) const {
// Handle non power of two vectors such as <3 x float>
if (VectorType *VTy = dyn_cast<VectorType>(Src)) {
unsigned NumElem = VTy->getVectorNumElements();
// Handle a few common cases:
// <3 x float>
if (NumElem == 3 && VTy->getScalarSizeInBits() == 32)
// Cost = 64 bit store + extract + 32 bit store.
return 3;
// <3 x double>
if (NumElem == 3 && VTy->getScalarSizeInBits() == 64)
// Cost = 128 bit store + unpack + 64 bit store.
return 3;
// Assume that all other non power-of-two numbers are scalarized.
if (!isPowerOf2_32(NumElem)) {
unsigned Cost = TargetTransformInfo::getMemoryOpCost(Opcode,
VTy->getScalarType(),
Alignment,
AddressSpace);
unsigned SplitCost = getScalarizationOverhead(Src,
Opcode == Instruction::Load,
Opcode==Instruction::Store);
return NumElem * Cost + SplitCost;
}
}
// Legalize the type.
std::pair<unsigned, MVT> LT = TLI->getTypeLegalizationCost(Src);
assert((Opcode == Instruction::Load || Opcode == Instruction::Store) &&

19
test/Analysis/CostModel/X86/load_store.ll
View File

@ -59,6 +59,25 @@ define i32 @loads(i32 %arg) {
;CHECK: cost of 4 {{.*}} load
load <8 x i64>* undef, align 4
;CHECK: cost of 3 {{.*}} load
load <3 x float>* undef, align 4
;CHECK: cost of 3 {{.*}} load
load <3 x double>* undef, align 4
;CHECK: cost of 3 {{.*}} load
load <3 x i32>* undef, align 4
;CHECK: cost of 3 {{.*}} load
load <3 x i64>* undef, align 4
;CHECK: cost of 10 {{.*}} load
load <5 x i32>* undef, align 4
;CHECK: cost of 10 {{.*}} load
load <5 x i64>* undef, align 4
ret i32 undef
}