From a70d1384571a104d5c9d1363c02d7b8689df6038 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Sun, 17 Feb 2008 20:51:26 +0000 Subject: Split up subtracts into add+negate if they have a reassociable use or operand that is also a subtract. This implements PR2047 and Transforms/Reassociate/subtest2.ll llvm-svn: 47241 --- llvm/lib/Transforms/Scalar/Reassociate.cpp | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) (limited to 'llvm/lib/Transforms/Scalar/Reassociate.cpp') diff --git a/llvm/lib/Transforms/Scalar/Reassociate.cpp b/llvm/lib/Transforms/Scalar/Reassociate.cpp index d0537ea8c43..bec91dbe67c 100644 --- a/llvm/lib/Transforms/Scalar/Reassociate.cpp +++ b/llvm/lib/Transforms/Scalar/Reassociate.cpp @@ -399,13 +399,16 @@ static bool ShouldBreakUpSubtract(Instruction *Sub) { return false; // Don't bother to break this up unless either the LHS is an associable add or - // if this is only used by one. - if (isReassociableOp(Sub->getOperand(0), Instruction::Add)) + // subtract or if this is only used by one. + if (isReassociableOp(Sub->getOperand(0), Instruction::Add) || + isReassociableOp(Sub->getOperand(0), Instruction::Sub)) return true; - if (isReassociableOp(Sub->getOperand(1), Instruction::Add)) + if (isReassociableOp(Sub->getOperand(1), Instruction::Add) || + isReassociableOp(Sub->getOperand(0), Instruction::Sub)) return true; - - if (Sub->hasOneUse() && isReassociableOp(Sub->use_back(), Instruction::Add)) + if (Sub->hasOneUse() && + (isReassociableOp(Sub->use_back(), Instruction::Add) || + isReassociableOp(Sub->use_back(), Instruction::Sub))) return true; return false; -- cgit v1.2.3