[InstCombine] sdiv exact flag fixup.
Differential Revision: https://reviews.llvm.org/D60396
llvm-svn: 357904
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
index 6d743a2..d5a36e0 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -1693,8 +1693,11 @@
// 0 - (X sdiv C) -> (X sdiv -C) provided the negation doesn't overflow.
if (match(Op1, m_SDiv(m_Value(X), m_Constant(C))) && match(Op0, m_Zero()) &&
- C->isNotMinSignedValue() && !C->isOneValue())
- return BinaryOperator::CreateSDiv(X, ConstantExpr::getNeg(C));
+ C->isNotMinSignedValue() && !C->isOneValue()) {
+ auto *BO = BinaryOperator::CreateSDiv(X, ConstantExpr::getNeg(C));
+ BO->setIsExact(cast<BinaryOperator>(Op1)->isExact());
+ return BO;
+ }
// 0 - (X << Y) -> (-X << Y) when X is freely negatable.
if (match(Op1, m_Shl(m_Value(X), m_Value(Y))) && match(Op0, m_Zero()))