[PATCH] D18944: [DAGCombiner] Fold xor/and/or (bitcast(A), bitcast(B)) -> bitcast(op (A, B)) anytime before LegalizeVectorOprs

[Simon Pilgrim via llvm-commits]

RKSimon created this revision.
RKSimon added reviewers: qcolombet, delena, spatel, andreadb.
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xor/and/or (bitcast(A), bitcast(B)) -> bitcast(op (A,B)) was only being combined at the AfterLegalizeTypes stage, this patch permits the combine to occur anytime before then as well.

My aim with this to improve the ability to recognise bitmasks that can be coverted to shuffles.

Elena - I had to modify a number of AVX512 mask tests as the basic bitcast to/from scalar pattern was being stripped out preventing testing of the mmask bitops. By replacing the bitcasts with loads I can get almost the same result.

Repository:
  rL LLVM

http://reviews.llvm.org/D18944

Files:
  lib/CodeGen/SelectionDAG/DAGCombiner.cpp
  test/CodeGen/X86/avx512-mask-op.ll
  test/CodeGen/X86/avx512-select.ll
  test/CodeGen/X86/avx512bw-mask-op.ll
  test/CodeGen/X86/avx512dq-mask-op.ll
  test/CodeGen/X86/vector-shuffle-128-v4.ll
  test/CodeGen/X86/vector-shuffle-128-v8.ll

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