[all-commits] [llvm/llvm-project] ea9e6a: [X86] getAVX512Node() - find constant broadcasts t...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: ea9e6aa423efd1e35c470e1b315146c66c1b3c42
      https://github.com/llvm/llvm-project/commit/ea9e6aa423efd1e35c470e1b315146c66c1b3c42
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2021-11-15 (Mon, 15 Nov 2021)

  Changed paths:
    M llvm/lib/Target/X86/X86ISelLowering.cpp
    M llvm/test/CodeGen/X86/avx512fp16-arith.ll
    M llvm/test/CodeGen/X86/min-legal-vector-width.ll
    M llvm/test/CodeGen/X86/vector-fshl-128.ll
    M llvm/test/CodeGen/X86/vector-fshl-256.ll
    M llvm/test/CodeGen/X86/vector-fshl-512.ll
    M llvm/test/CodeGen/X86/vector-fshl-rot-128.ll
    M llvm/test/CodeGen/X86/vector-fshl-rot-256.ll
    M llvm/test/CodeGen/X86/vector-fshl-rot-512.ll
    M llvm/test/CodeGen/X86/vector-fshr-128.ll
    M llvm/test/CodeGen/X86/vector-fshr-256.ll
    M llvm/test/CodeGen/X86/vector-fshr-512.ll
    M llvm/test/CodeGen/X86/vector-fshr-rot-128.ll
    M llvm/test/CodeGen/X86/vector-fshr-rot-256.ll
    M llvm/test/CodeGen/X86/vector-fshr-rot-512.ll
    M llvm/test/CodeGen/X86/vector-rotate-128.ll
    M llvm/test/CodeGen/X86/vector-rotate-256.ll
    M llvm/test/CodeGen/X86/vector-rotate-512.ll

  Log Message:
  -----------
  [X86] getAVX512Node() - find constant broadcasts to encourage load-folding

If an operand is a bitcasted or widended constant, try to more aggressively create broadcastable constants for folding, which in particular helps non-VLX modes.

I've refactored getAVX512Node so that VLX targets can make better use of this as well.

NOTE: In the future, I think we should consider removing the broadcast of constant data from DAG entirely and move this to either X86InstrInfo::foldMemoryOperand or a new pass - AVX1/2 targets has similar problems with missed (whole vector) folds that need to be improved as well.

Differential Revision: https://reviews.llvm.org/D113845