From 67920320b26cbc8c1203ee94654ac1ce1fd2af13 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Sat, 15 Jan 2011 05:50:18 +0000 Subject: [PATCH] one more instcombine variant that is needed to work with future changes, no functionality change currently. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123517 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/InstCombine/InstCombineAddSub.cpp | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/lib/Transforms/InstCombine/InstCombineAddSub.cpp index c4132b2435c..e5d9a8b9618 100644 --- a/lib/Transforms/InstCombine/InstCombineAddSub.cpp +++ b/lib/Transforms/InstCombine/InstCombineAddSub.cpp @@ -672,6 +672,15 @@ Instruction *InstCombiner::visitSub(BinaryOperator &I) { Value *NewMul = Builder->CreateMul(A, B); return BinaryOperator::CreateAdd(Op0, NewMul); } + + // X - A*Cst -> X + A*-Cst + // X - Cst*A -> X + A*-Cst + ConstantInt *BCst; + if (match(Op1I, m_Mul(m_Value(A), m_ConstantInt(BCst))) || + match(Op1I, m_Mul(m_ConstantInt(BCst), m_Value(A)))) { + Value *NewMul = Builder->CreateMul(A, ConstantExpr::getNeg(BCst)); + return BinaryOperator::CreateAdd(Op0, NewMul); + } } }