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Use the isTruncFree and isZExtFree API to figure out of these operations are free. Thanks Andy! 

llvm-svn: 167685
This commit is contained in:
Nadav Rotem 2012-11-11 05:34:45 +00:00
parent 12930749ab
commit 3b99dc62a7
1 changed files with 10 additions and 2 deletions
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12
llvm/lib/Target/TargetTransformImpl.cpp
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@ -214,8 +214,16 @@ unsigned VectorTargetTransformImpl::getCastInstrCost(unsigned Opcode, Type *Dst,
// Handle scalar conversions.
if (!Src->isVectorTy() && !Dst->isVectorTy()) {
// Scalar bitcasts and truncs are usually free.
if (Opcode == Instruction::BitCast || Opcode == Instruction::Trunc)
// Scalar bitcasts are usually free.
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.