From f73ff612cabc043d481b6fdd3b5e7cd92d5f0706 Mon Sep 17 00:00:00 2001 From: Craig Topper Date: Tue, 13 Feb 2018 16:25:27 +0000 Subject: [DAGCombiner] Add one use check to fold (not (and x, y)) -> (or (not x), (not y)) Summary: If the and has an additional use we shouldn't invert it. That creates an additional instruction. While there add a one use check to the transform above that looked similar. Reviewers: spatel, RKSimon Reviewed By: RKSimon Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D43225 llvm-svn: 325019 --- llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'llvm/lib') diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 1c32a92ddad..ac981d0457e 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -5398,7 +5398,7 @@ SDValue DAGCombiner::visitXOR(SDNode *N) { } // fold (not (or x, y)) -> (and (not x), (not y)) iff x or y are setcc - if (isOneConstant(N1) && VT == MVT::i1 && + if (isOneConstant(N1) && VT == MVT::i1 && N0.hasOneUse() && (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) { SDValue LHS = N0.getOperand(0), RHS = N0.getOperand(1); if (isOneUseSetCC(RHS) || isOneUseSetCC(LHS)) { @@ -5410,7 +5410,7 @@ SDValue DAGCombiner::visitXOR(SDNode *N) { } } // fold (not (or x, y)) -> (and (not x), (not y)) iff x or y are constants - if (isAllOnesConstant(N1) && + if (isAllOnesConstant(N1) && N0.hasOneUse() && (N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) { SDValue LHS = N0.getOperand(0), RHS = N0.getOperand(1); if (isa(RHS) || isa(LHS)) { -- cgit v1.2.3