Scalar Bitcasts and Truncs are usually free
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167323 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/TargetTransformImpl.cpp b/lib/Target/TargetTransformImpl.cpp
index dbbf37a..4cd07cd 100644
--- a/lib/Target/TargetTransformImpl.cpp
+++ b/lib/Target/TargetTransformImpl.cpp
@@ -213,6 +213,11 @@
// Handle scalar conversions.
if (!Src->isVectorTy() && !Dst->isVectorTy()) {
+
+ // Scalar bitcasts and truncs are usually free.
+ if (Opcode == Instruction::BitCast || Opcode == Instruction::Trunc)
+ 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;