diff options
Diffstat (limited to 'llvm/lib/Transforms')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp | 18 |
1 files changed, 10 insertions, 8 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp index 8bc34825f8a..5b71f9d9c2e 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp @@ -1896,14 +1896,16 @@ Instruction *InstCombiner::visitSub(BinaryOperator &I) { Builder.CreateNot(Y, Y->getName() + ".not")); // 0 - (X sdiv C) -> (X sdiv -C) provided the negation doesn't overflow. - // TODO: This could be extended to match arbitrary vector constants. - const APInt *DivC; - if (match(Op0, m_Zero()) && match(Op1, m_SDiv(m_Value(X), m_APInt(DivC))) && - !DivC->isMinSignedValue() && *DivC != 1) { - Constant *NegDivC = ConstantInt::get(I.getType(), -(*DivC)); - Instruction *BO = BinaryOperator::CreateSDiv(X, NegDivC); - BO->setIsExact(cast<BinaryOperator>(Op1)->isExact()); - return BO; + if (match(Op0, m_Zero())) { + Constant *Op11C; + if (match(Op1, m_SDiv(m_Value(X), m_Constant(Op11C))) && + !Op11C->containsUndefElement() && Op11C->isNotMinSignedValue() && + Op11C->isNotOneValue()) { + Instruction *BO = + BinaryOperator::CreateSDiv(X, ConstantExpr::getNeg(Op11C)); + BO->setIsExact(cast<BinaryOperator>(Op1)->isExact()); + return BO; + } } // 0 - (X << Y) -> (-X << Y) when X is freely negatable. |
