commit 01d22aaa78b831ad4837f928e0554be7e65addaa
author Craig Topper <craig.topper@gmail.com> Thu Aug 08 07:38:55 2013 +0000
committer Craig Topper <craig.topper@gmail.com> Thu Aug 08 07:38:55 2013 +0000
tree f58a4bf1b247e302455d29612f29f66403d3914c
parent 05a4d2642b415e3332651733015b656bc3c7b9bc

Optimize mask generation for one of the DAG combiner shufflevector cases.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187961 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/SelectionDAG/DAGCombiner.cpp

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index cb88941..0d71761 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -9358,10 +9358,10 @@
     for (unsigned i = 0; i != NumElts; ++i) {
       int Idx = SVN->getMaskElt(i);
       if (Idx >= 0) {
-        if (Idx < (int)NumElts)
-          Idx += NumElts;
-        else
+        if (Idx >= (int)NumElts)
           Idx -= NumElts;
+        else
+          Idx = -1; // remove reference to lhs
       }
       NewMask.push_back(Idx);
     }