commit c82751dd6761e3db62668b6b1cfddd4f659855b6
author Eli Friedman <eli.friedman@gmail.com> Thu Sep 15 01:14:29 2011 +0000
committer Eli Friedman <eli.friedman@gmail.com> Thu Sep 15 01:14:29 2011 +0000
tree 7dfc93f730b3f9176ae6dc6cf0dff2d6f96b1250
parent b1afbac64b7c4c06959350acc175fb3552012f57

Make demanded-elt simplification for shufflevector slightly stronger.  Spotted by inspection.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139768 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp

diff --git a/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp b/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
index 66f39be..81929bc 100644
--- a/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
+++ b/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
@@ -962,6 +962,9 @@
       unsigned MaskVal = Shuffle->getMaskValue(i);
       if (MaskVal == -1u) {
         UndefElts.setBit(i);
+      } else if (!DemandedElts[i]) {
+        NewUndefElts = true;
+        UndefElts.setBit(i);
       } else if (MaskVal < LHSVWidth) {
         if (UndefElts4[MaskVal]) {
           NewUndefElts = true;