From f79e60649a5edea03bdccf8521d77c15cbb33af4 Mon Sep 17 00:00:00 2001 From: Evan Cheng Date: Mon, 10 Mar 2008 07:19:13 +0000 Subject: Avoid creating BUILD_VECTOR of all zero elements of "non-normalized" type (e.g. v8i16 on x86) after legalizer. Instruction selection does not expect to see them. In all likelihood this can only be an issue in a bugpoint reduced test case. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48136 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'lib/CodeGen') diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 963a1feba8..1b00855a67 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -1103,6 +1103,10 @@ SDOperand DAGCombiner::visitSUB(SDNode *N) { // fold (sub x, x) -> 0 if (N0 == N1) + if (ISD::isBuildVectorAllZeros(N0.Val)) + // Zero vectors might be normalized to a particular vector type to ensure + // they are CSE'd. Return it as it is. + return N0; return DAG.getConstant(0, N->getValueType(0)); // fold (sub c1, c2) -> c1-c2 if (N0C && N1C) -- cgit v1.2.3-18-g5258