Use the isTruncFree and isZExtFree API to figure out of these operations are free. Thanks Andy!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167685 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/TargetTransformImpl.cpp b/lib/Target/TargetTransformImpl.cpp
index c07332d..b36e6f8 100644
--- a/lib/Target/TargetTransformImpl.cpp
+++ b/lib/Target/TargetTransformImpl.cpp
@@ -214,8 +214,16 @@
// 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.