From 91ccc15b454e10f6c0bd3b66fff5fcd84f3c19c2 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Wed, 6 Oct 2004 15:08:25 +0000 Subject: [PATCH] Instcombine: -(X sdiv C) -> (X sdiv -C), tested by sub.ll:test16 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16769 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Scalar/InstructionCombining.cpp | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index 6db0717a9fc..767fc9582b0 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -746,6 +746,14 @@ Instruction *InstCombiner::visitSub(BinaryOperator &I) { return BinaryOperator::createAnd(Op0, NewNot); } + // -(X sdiv C) -> (X sdiv -C) + if (Op1I->getOpcode() == Instruction::Div) + if (ConstantSInt *CSI = dyn_cast(Op0)) + if (CSI->getValue() == 0) + if (Constant *DivRHS = dyn_cast(Op1I->getOperand(1))) + return BinaryOperator::createDiv(Op1I->getOperand(0), + ConstantExpr::getNeg(DivRHS)); + // X - X*C --> X * (1-C) if (dyn_castFoldableMul(Op1I) == Op0) { Constant *CP1 =