From 99b653c36f0141f6b9515d688960ac8c2cb857ff Mon Sep 17 00:00:00 2001 From: Evan Cheng Date: Tue, 15 Dec 2009 00:41:36 +0000 Subject: Propagate zest through logical shift. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91378 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'lib') diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 027348c..52b7ed5 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -3278,6 +3278,16 @@ SDValue DAGCombiner::visitZERO_EXTEND(SDNode *N) { if (SCC.getNode()) return SCC; } + // (zext (shl (zext x), y)) -> (shl (zext x), (zext y)) + if ((N0.getOpcode() == ISD::SHL || N0.getOpcode() == ISD::SRL) && + N0.getOperand(0).getOpcode() == ISD::ZERO_EXTEND && + N0.hasOneUse()) { + DebugLoc dl = N->getDebugLoc(); + return DAG.getNode(N0.getOpcode(), dl, VT, + DAG.getNode(ISD::ZERO_EXTEND, dl, VT, N0.getOperand(0)), + DAG.getNode(ISD::ZERO_EXTEND, dl, VT, N0.getOperand(1))); + } + return SDValue(); } -- cgit v1.1