[all-commits] [llvm/llvm-project] 25dd67: [X86][AVX] foldShuffleOfHorizOp - don't attempt to...

[Tom Stellard via All-commits]

  Branch: refs/heads/release/12.x
  Home:   https://github.com/llvm/llvm-project
  Commit: 25dd67ef882c327f9b6a3082cab6c33c9ff52d42
      https://github.com/llvm/llvm-project/commit/25dd67ef882c327f9b6a3082cab6c33c9ff52d42
  Author: Tom Stellard <tstellar at redhat.com>
  Date:   2021-04-29 (Thu, 29 Apr 2021)

  Changed paths:
    M llvm/lib/Target/X86/X86ISelLowering.cpp
    M llvm/test/CodeGen/X86/horizontal-shuffle-3.ll

  Log Message:
  -----------
  [X86][AVX] foldShuffleOfHorizOp - don't attempt to handle 256-bit X86ISD::VBROADCAST (PR49971)

NOTE: This is for the 12.x release branch ONLY

Minimal patch to avoid the issue encountered in PR49971 (it's already been dealt with in trunk through a larger refactor that can't be easily merged).

Bail for non-128-bit vector broadcasts of (F)HADD/SUB ops - the existing logic doesn't correctly deal with the fact that the broadcast will splat across the 128-bit lanes.

Reviewed By: spatel, wristow

Differential Revision: https://reviews.llvm.org/D101104