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ARM Cost Model: Modify the target independent cost model to ask

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the target if it supports the different CAST types. We didn't do this
on X86 because of the different register sizes and types, but on ARM
this makes sense.

llvm-svn: 172245
This commit is contained in:
Nadav Rotem
2013-01-11 19:54:13 +00:00
parent 46afb35181
commit e55aa3c848
2 changed files with 24 additions and 15 deletions
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33
llvm/lib/CodeGen/BasicTargetTransformInfo.cpp
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@@ -241,6 +241,27 @@ unsigned BasicTTI::getCastInstrCost(unsigned Opcode, Type *Dst,
std::pair<unsigned, MVT> SrcLT = TLI->getTypeLegalizationCost(Src);
std::pair<unsigned, MVT> DstLT = TLI->getTypeLegalizationCost(Dst);
// Check for NOOP conversions.
if (SrcLT.first == DstLT.first &&
SrcLT.second.getSizeInBits() == DstLT.second.getSizeInBits()) {
// Bitcast between types that are legalized to the same type are free.
if (Opcode == Instruction::BitCast || Opcode == Instruction::Trunc)
return 0;
}
if (Opcode == Instruction::Trunc &&
TLI->isTruncateFree(SrcLT.second, DstLT.second))
return 0;
if (Opcode == Instruction::ZExt &&
TLI->isZExtFree(SrcLT.second, DstLT.second))
return 0;
// If the cast is marked as legal (or promote) then assume low cost.
if (TLI->isOperationLegalOrPromote(ISD, DstLT.second))
return 1;
// Handle scalar conversions.
if (!Src->isVectorTy() && !Dst->isVectorTy()) {
@@ -248,14 +269,6 @@ unsigned BasicTTI::getCastInstrCost(unsigned Opcode, Type *Dst,
if (Opcode == Instruction::BitCast)
return 0;
if (Opcode == Instruction::Trunc &&
TLI->isTruncateFree(SrcLT.second, DstLT.second))
return 0;
if (Opcode == Instruction::ZExt &&
TLI->isZExtFree(SrcLT.second, DstLT.second))
return 0;
// Just check the op cost. If the operation is legal then assume it costs 1.
if (!TLI->isOperationExpand(ISD, DstLT.second))
return 1;
@@ -271,10 +284,6 @@ unsigned BasicTTI::getCastInstrCost(unsigned Opcode, Type *Dst,
if (SrcLT.first == DstLT.first &&
SrcLT.second.getSizeInBits() == DstLT.second.getSizeInBits()) {
// Bitcast between types that are legalized to the same type are free.
if (Opcode == Instruction::BitCast || Opcode == Instruction::Trunc)
return 0;
// Assume that Zext is done using AND.
if (Opcode == Instruction::ZExt)
return 1;