[PowerPC] Fix for PR33636

Remove casts to a constant when a node can be an undef. Differential Revision: https://reviews.llvm.org/D34808 llvm-svn: 307120
llvm · Jul 5, 2017 · 845a796 · 845a796
1 parent 5749559
commit 845a796
Show file tree

Hide file tree

Showing 2 changed files with 706 additions and 2 deletions.
diff --git a/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp b/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
@@ -4034,11 +4034,13 @@ void PPCDAGToDAGISel::foldBoolExts(SDValue &Res, SDNode *&N) {
                                             O0.getNode(), O1.getNode());
     };
 
+    // FIXME: When the semantics of the interaction between select and undef
+    // are clearly defined, it may turn out to be unnecessary to break here.
     SDValue TrueRes = TryFold(ConstTrue);
-    if (!TrueRes)
+    if (!TrueRes || TrueRes.isUndef())
       break;
     SDValue FalseRes = TryFold(ConstFalse);
-    if (!FalseRes)
+    if (!FalseRes || FalseRes.isUndef())
       break;
 
     // For us to materialize these using one instruction, we must be able to