[llvm] r271830 - [X86][XOP] Tidied up DecodeVPERMIL2PMask to more closely match DecodeVPERMILPMask.

[Simon Pilgrim via llvm-commits]

Author: rksimon
Date: Sun Jun  5 09:33:43 2016
New Revision: 271830

URL: http://llvm.org/viewvc/llvm-project?rev=271830&view=rev
Log:
[X86][XOP] Tidied up DecodeVPERMIL2PMask to more closely match DecodeVPERMILPMask. 

Modified:
    llvm/trunk/lib/Target/X86/X86ShuffleDecodeConstantPool.cpp

Modified: llvm/trunk/lib/Target/X86/X86ShuffleDecodeConstantPool.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ShuffleDecodeConstantPool.cpp?rev=271830&r1=271829&r2=271830&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ShuffleDecodeConstantPool.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ShuffleDecodeConstantPool.cpp Sun Jun  5 09:33:43 2016
@@ -212,9 +212,11 @@ void DecodeVPERMIL2PMask(const Constant
       continue;
     }
 
-    int Index = Selector & 0x3;
-    Index >>= (ElSize == 64 ? 1 : 0);
-    Index += (i / NumElementsPerLane) * NumElementsPerLane;
+    int Index = i & ~(NumElementsPerLane - 1);
+    if (ElSize == 64)
+      Index += (Selector >> 1) & 0x1;
+    else
+      Index += Selector & 0x3;
 
     int Src = (Selector >> 2) & 0x1;
     Index += Src * NumElements;