[PATCH] D37950: [X86] Rewrite the zero vector checks in lowerV2X128VectorShuffle to use the Zeroable APInt

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added inline comments.


================
Comment at: lib/Target/X86/X86ISelLowering.cpp:12212
 
-  unsigned PermMask = MaskLO | (MaskHI << 4);
+  bool V1Used = false, V2Used = false;
+  unsigned PermMask = 0;
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These look superfluous 


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Comment at: lib/Target/X86/X86ISelLowering.cpp:12222
+  else
+    PermMask |= WidenedMask[1] << 4;
 
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Use ternary operators?
```
PermMask |= IsLowZero ? 0x08 : WidenedMask[0];
PermMask |= IsHighZero ? 0x80 : WidenedMask[1];

```


https://reviews.llvm.org/D37950