From 153911f71d3a07d9dd131668a69283935a06c1c5 Mon Sep 17 00:00:00 2001 From: Amaury Sechet Date: Tue, 2 May 2017 13:34:25 +0000 Subject: [DAGCombine] (add X, (addcarry Y, 0, Carry)) -> (addcarry X, Y, Carry) Summary: Common pattern when legalizing large integers operations. Similar to D32687, when the carry isn't used. Reviewers: jyknight, nemanjai, mkuper, spatel, RKSimon, zvi, bkramer Differential Revision: https://reviews.llvm.org/D32738 llvm-svn: 301919 --- llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'llvm/lib/CodeGen') diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index c2200742add..559a8552959 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -2015,6 +2015,11 @@ SDValue DAGCombiner::visitADDLike(SDValue N0, SDValue N1, SDNode *LocReference) } } + // (add X, (addcarry Y, 0, Carry)) -> (addcarry X, Y, Carry) + if (N1.getOpcode() == ISD::ADDCARRY && isNullConstant(N1.getOperand(1))) + return DAG.getNode(ISD::ADDCARRY, DL, N1->getVTList(), + N0, N1.getOperand(0), N1.getOperand(2)); + return SDValue(); } -- cgit v1.2.3