[all-commits] [llvm/llvm-project] 43f60e: [x86] try harder to form 256-bit unpck*

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  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 43f60e614a3d30e1ae805996d93b1b433a39cf9d
      https://github.com/llvm/llvm-project/commit/43f60e614a3d30e1ae805996d93b1b433a39cf9d
  Author: Sanjay Patel <spatel at rotateright.com>
  Date:   2020-01-17 (Fri, 17 Jan 2020)

  Changed paths:
    M llvm/lib/Target/X86/X86ISelLowering.cpp
    M llvm/lib/Target/X86/X86ISelLowering.h
    M llvm/test/CodeGen/X86/vector-interleave.ll
    M llvm/test/CodeGen/X86/vector-shuffle-256-v8.ll

  Log Message:
  -----------
  [x86] try harder to form 256-bit unpck*

This is another part of a problem noted in PR42024:
https://bugs.llvm.org/show_bug.cgi?id=42024

The AVX2 code may use awkward 256-bit shuffles vs. the AVX code that gets split
into the expected 128-bit unpack instructions. We have to be selective in
matching the types where we try to do this though. Otherwise, we can end up
with more instructions (in the case of v8x32/v4x64).

Differential Revision: https://reviews.llvm.org/D72575