[all-commits] [llvm/llvm-project] 046c57: Revert "[SLP]Improve tryToGatherExtractElements by...

[Hans via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 046c57e705e082566e2d0073a2f21471a2b06a19
      https://github.com/llvm/llvm-project/commit/046c57e705e082566e2d0073a2f21471a2b06a19
  Author: Hans Wennborg <hans at chromium.org>
  Date:   2023-11-06 (Mon, 06 Nov 2023)

  Changed paths:
    M llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
    M llvm/test/Transforms/SLPVectorizer/AArch64/extractelements-to-shuffle.ll
    M llvm/test/Transforms/SLPVectorizer/X86/crash_clear_undefs.ll
    M llvm/test/Transforms/SLPVectorizer/X86/hadd-inseltpoison.ll
    M llvm/test/Transforms/SLPVectorizer/X86/hadd.ll
    M llvm/test/Transforms/SLPVectorizer/X86/hsub-inseltpoison.ll
    M llvm/test/Transforms/SLPVectorizer/X86/hsub.ll
    M llvm/test/Transforms/SLPVectorizer/X86/reused-extractelements.ll

  Log Message:
  -----------
  Revert "[SLP]Improve tryToGatherExtractElements by using per-register analysis."

This causes asserts:

  llvm-project/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:10082:
  Value *llvm::slpvectorizer::BoUpSLP::ShuffleInstructionBuilder::adjustExtracts(
    const TreeEntry *, MutableArrayRef<int>, unsigned int, bool &):
  Assertion `Part == 0 && "Expected firs part."' failed.

See comment on the code review.

> Currently tryToGatherExtractElements function analyzes the whole vector,
> regrdless number of actual registers, used in this vector. It may
> prevent some optimizations, because per-register analysis may allow to
> simplify the final code by reusing more already emitted vectors and
> better shuffles.
>
> Differential Revision: https://reviews.llvm.org/D148855

This reverts commit 9dfdbd788707edc8c39eb2bff16004aba1f3586b.