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path: root/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
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Diffstat (limited to 'lib/Transforms/InstCombine/InstCombineMulDivRem.cpp')
-rw-r--r--lib/Transforms/InstCombine/InstCombineMulDivRem.cpp21
1 files changed, 17 insertions, 4 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
index 78f585f6f73..010625a7157 100644
--- a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -295,10 +295,23 @@ Instruction *InstCombiner::visitMul(BinaryOperator &I) {
// (1 << Y)*X --> X << Y
{
Value *Y;
- if (match(Op0, m_Shl(m_One(), m_Value(Y))))
- return BinaryOperator::CreateShl(Op1, Y);
- if (match(Op1, m_Shl(m_One(), m_Value(Y))))
- return BinaryOperator::CreateShl(Op0, Y);
+ BinaryOperator *BO = nullptr;
+ bool ShlNSW = false;
+ if (match(Op0, m_Shl(m_One(), m_Value(Y)))) {
+ BO = BinaryOperator::CreateShl(Op1, Y);
+ ShlNSW = cast<BinaryOperator>(Op0)->hasNoSignedWrap();
+ }
+ if (match(Op1, m_Shl(m_One(), m_Value(Y)))) {
+ BO = BinaryOperator::CreateShl(Op0, Y);
+ ShlNSW = cast<BinaryOperator>(Op1)->hasNoSignedWrap();
+ }
+ if (BO) {
+ if (I.hasNoUnsignedWrap())
+ BO->setHasNoUnsignedWrap();
+ if (I.hasNoSignedWrap() && ShlNSW)
+ BO->setHasNoSignedWrap();
+ return BO;
+ }
}
// If one of the operands of the multiply is a cast from a boolean value, then