[InstCombine] don't form select from bitcasted logic ops if bitcasts have >1 use

This isn't a sure thing (are 2 extra bitcasts less expensive than a logic op?), 
but we'll try to err on the conservative side by going with the case that has
less IR instructions.

Note: This question came up in http://reviews.llvm.org/D22114 , but this part is
independent of that patch proposal, so I'm making this small change ahead of that
one. 

See also:
http://reviews.llvm.org/rL274926

llvm-svn: 274932

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index 3865572e816..01a5152131b 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -1619,8 +1619,8 @@ static Value *matchSelectFromAndOr(Value *A, Value *C, Value *B, Value *D,
   // through its bitcast and the corresponding bitcast of the 'not' condition.
   Type *OrigType = A->getType();
   Value *SrcA, *SrcB;
-  if (match(A, m_BitCast(m_Value(SrcA))) &&
-      match(B, m_BitCast(m_Value(SrcB)))) {
+  if (match(A, m_OneUse(m_BitCast(m_Value(SrcA)))) &&
+      match(B, m_OneUse(m_BitCast(m_Value(SrcB))))) {
     A = SrcA;
     B = SrcB;
   }