diff options
Diffstat (limited to 'lib/Transforms/InstCombine/InstCombineMulDivRem.cpp')
| -rw-r--r-- | lib/Transforms/InstCombine/InstCombineMulDivRem.cpp | 21 |
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 |