From 492fd454ca3aa3d45e76c4f42b602e934cf519b1 Mon Sep 17 00:00:00 2001 From: Bob Wilson Date: Wed, 19 May 2010 23:42:58 +0000 Subject: Optimize away insertelement of an undef value. This shows up in test/Codegen/ARM/reg_sequence.ll but it doesn't affect the generated code because the coalescer cleans it up. Radar 7998853. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104185 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'lib') diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 347024f..0ea46af 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -6024,6 +6024,10 @@ SDValue DAGCombiner::visitINSERT_VECTOR_ELT(SDNode *N) { SDValue InVal = N->getOperand(1); SDValue EltNo = N->getOperand(2); + // If the inserted element is an UNDEF, just use the input vector. + if (InVal.getOpcode() == ISD::UNDEF) + return InVec; + // If the invec is a BUILD_VECTOR and if EltNo is a constant, build a new // vector with the inserted element. if (InVec.getOpcode() == ISD::BUILD_VECTOR && isa(EltNo)) { -- cgit v1.1