[PATCH] D34601: [X86][LLVM]Expanding Supports lowerInterleavedStore() in X86InterleavedAccess.

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added inline comments.


================
Comment at: lib/Target/X86/X86ISelLowering.h:1457
+  /// succeed.
+  template <typename T>
+  void scaleShuffleMask(int Scale, ArrayRef<T> Mask,
----------------
DavidKreitzer wrote:
> Did you want to have T default to int as you did for createUnpackShuffleMask? That will avoid the extra changes in X86ISelLowering.cpp.
> 
+1


================
Comment at: lib/Target/X86/X86InterleavedAccess.cpp:175
+//  Low = true:  mask generated for the shuffle
+//  shufle(VEC1,VEC2,{0,1,2,...,NumElement/2-1,NumElement,
+//                    NumElement+1...,NumElement+NumElement/2-1})
----------------
shuffle


================
Comment at: lib/Target/X86/X86InterleavedAccess.cpp:188
+  }
+}
+
----------------
I think you could make this much simpler to understand:
```
int NumHalfElements = NumElement / 2;
int Offset = Low ? 0 : NumHalfElements;
for (int i = 0; i < NumHalfElements; ++i)
  Mask.push_back(i + Offset);
for (int i = 0; i < NumHalfElements; ++i)
  Mask.push_back(i + Offset + NumElements);
```


https://reviews.llvm.org/D34601