[PATCH] D27087: [AVX-512] Add support for changing VSHUFF64x2 to VSHUFF32x4 when its feeding a vselect with 32-bit element size.

[Craig Topper via llvm-commits]

craig.topper created this revision.
craig.topper added reviewers: RKSimon, delena, zvi.
craig.topper added a subscriber: llvm-commits.

Shuffle lowering may have widened the element size of a i32 shuffle to i64 before selecting X86ISD::SHUF128. If this shuffle was used by a vselect this can prevent us from selecting masked operations.

This patch detects this and changes the element size to match the vselect.

I don't handle changing integer to floating point or vice versa as its not clear if its better to push such a bitcast to the inputs of the shuffle or to the user of the vselect. So I'm ignoring that case for now.


https://reviews.llvm.org/D27087

Files:
  lib/Target/X86/X86ISelLowering.cpp
  test/CodeGen/X86/vector-shuffle-512-v16.ll

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