diff options
Diffstat (limited to 'lib/Transforms/InstCombine/InstCombineMulDivRem.cpp')
-rw-r--r-- | lib/Transforms/InstCombine/InstCombineMulDivRem.cpp | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp index 9996ebc..6c6e7d8 100644 --- a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp +++ b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp @@ -203,8 +203,11 @@ Instruction *InstCombiner::visitMul(BinaryOperator &I) { Value *X; Constant *C1; if (match(Op0, m_OneUse(m_Add(m_Value(X), m_Constant(C1))))) { - Value *Add = Builder->CreateMul(X, Op1); - return BinaryOperator::CreateAdd(Add, Builder->CreateMul(C1, Op1)); + Value *Mul = Builder->CreateMul(C1, Op1); + // Only go forward with the transform if C1*CI simplifies to a tidier + // constant. + if (!match(Mul, m_Mul(m_Value(), m_Value()))) + return BinaryOperator::CreateAdd(Builder->CreateMul(X, Op1), Mul); } } } @@ -990,6 +993,10 @@ Instruction *InstCombiner::visitSDiv(BinaryOperator &I) { } if (Constant *RHS = dyn_cast<Constant>(Op1)) { + // X/INT_MIN -> X == INT_MIN + if (RHS->isMinSignedValue()) + return new ZExtInst(Builder->CreateICmpEQ(Op0, Op1), I.getType()); + // -X/C --> X/-C provided the negation doesn't overflow. if (SubOperator *Sub = dyn_cast<SubOperator>(Op0)) if (match(Sub->getOperand(0), m_Zero()) && Sub->hasNoSignedWrap()) |