[all-commits] [llvm/llvm-project] 064cd2: [x86] allow peeking through an extract_subvector t...

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  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 064cd2ecdb3d0c52be5b6cf4fc67125baa714d3a
      https://github.com/llvm/llvm-project/commit/064cd2ecdb3d0c52be5b6cf4fc67125baa714d3a
  Author: Sanjay Patel <spatel at rotateright.com>
  Date:   2020-02-20 (Thu, 20 Feb 2020)

  Changed paths:
    M llvm/lib/Target/X86/X86ISelLowering.cpp
    M llvm/test/CodeGen/X86/avx-intrinsics-fast-isel.ll
    M llvm/test/CodeGen/X86/avx-splat.ll
    M llvm/test/CodeGen/X86/avx512-shuffles/partial_permute.ll
    M llvm/test/CodeGen/X86/bitcast-int-to-vector-bool-sext.ll
    M llvm/test/CodeGen/X86/bitcast-int-to-vector-bool-zext.ll
    M llvm/test/CodeGen/X86/extractelement-load.ll
    M llvm/test/CodeGen/X86/fma.ll
    M llvm/test/CodeGen/X86/insertelement-var-index.ll
    M llvm/test/CodeGen/X86/masked_gather.ll
    M llvm/test/CodeGen/X86/pr34653.ll
    M llvm/test/CodeGen/X86/vector-shuffle-512-v32.ll
    M llvm/test/CodeGen/X86/x86-interleaved-access.ll

  Log Message:
  -----------
  [x86] allow peeking through an extract_subvector to find a splatted operand

The motivating case is seen in "splat4_v8f32_load_store" and based on code in PR42024:
https://bugs.llvm.org/show_bug.cgi?id=42024
(I haven't stepped through the v8i32 sibling test yet to see why that diverged.)

There are other potential improvements visible like allowing scalarization or vector
narrowing.

Differential Revision: https://reviews.llvm.org/D74909