Clean up some of the shuffle decoding code for UNPCK instructions. Add instruction commenting for AVX/AVX2 forms for integer UNPCKs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145924 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 7df931f..169e41b 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -4461,16 +4461,12 @@
                       ShuffleMask);
       break;
     case X86ISD::PUNPCKH:
-      DecodePUNPCKHMask(NumElems, ShuffleMask);
-      break;
     case X86ISD::UNPCKHP:
-      DecodeUNPCKHPMask(VT, ShuffleMask);
+      DecodeUNPCKHMask(VT, ShuffleMask);
       break;
     case X86ISD::PUNPCKL:
-      DecodePUNPCKLMask(VT, ShuffleMask);
-      break;
     case X86ISD::UNPCKLP:
-      DecodeUNPCKLPMask(VT, ShuffleMask);
+      DecodeUNPCKLMask(VT, ShuffleMask);
       break;
     case X86ISD::MOVHLPS:
       DecodeMOVHLPSMask(NumElems, ShuffleMask);