[llvm] r290183 - [X86][SSE] Ensure we're only combining shuffles with legal mask types.

[Simon Pilgrim via llvm-commits]

Author: rksimon
Date: Tue Dec 20 11:09:52 2016
New Revision: 290183

URL: http://llvm.org/viewvc/llvm-project?rev=290183&view=rev
Log:
[X86][SSE] Ensure we're only combining shuffles with legal mask types.

I haven't managed to get this to fail yet but its technically possible for the AND -> shuffle decomposition to result in illegal types.

Modified:
    llvm/trunk/lib/Target/X86/X86ISelLowering.cpp

Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=290183&r1=290182&r2=290183&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Tue Dec 20 11:09:52 2016
@@ -26460,6 +26460,10 @@ static bool combineX86ShuffleChain(Array
                            : MVT::getIntegerVT(MaskEltSizeInBits);
   MaskVT = MVT::getVectorVT(MaskVT, NumMaskElts);
 
+  // Only allow legal mask types.
+  if (!DAG.getTargetLoweringInfo().isTypeLegal(MaskVT))
+    return false;
+
   // Attempt to match the mask against known shuffle patterns.
   MVT ShuffleSrcVT, ShuffleVT;
   unsigned Shuffle, PermuteImm;