[InstCombine] add hasOneUse check to add-zext-add fold to prevent increasing instructions
llvm-svn: 315718
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
index 92452d7..3921ab4 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -988,10 +988,8 @@
return CastInst::Create(Instruction::SExt, X, Ty);
// (add (zext (add nuw X, C2)), C) --> (zext (add nuw X, C2 + C))
- // FIXME: This should check hasOneUse to not increase the instruction count?
- if (C->isNegative() &&
- match(Op0, m_ZExt(m_NUWAdd(m_Value(X), m_APInt(C2)))) &&
- C->sge(-C2->sext(C->getBitWidth()))) {
+ if (match(Op0, m_OneUse(m_ZExt(m_NUWAdd(m_Value(X), m_APInt(C2))))) &&
+ C->isNegative() && C->sge(-C2->sext(C->getBitWidth()))) {
Constant *NewC =
ConstantInt::get(X->getType(), *C2 + C->trunc(C2->getBitWidth()));
return new ZExtInst(Builder.CreateNUWAdd(X, NewC), Ty);