[all-commits] [llvm/llvm-project] 824251: Revert "[RISCV] Generaize reduction tree matching ...

[Alex Bradbury via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 824251c9b349d859a9169196cd9533c619a715ce
      https://github.com/llvm/llvm-project/commit/824251c9b349d859a9169196cd9533c619a715ce
  Author: Alex Bradbury <asb at igalia.com>
  Date:   2023-10-04 (Wed, 04 Oct 2023)

  Changed paths:
    M llvm/lib/Target/RISCV/RISCVISelLowering.cpp
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-int-explodevector.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-reduction-formation.ll

  Log Message:
  -----------
  Revert "[RISCV] Generaize reduction tree matching to all integer reductions (#68014)"

This reverts commit 7a0b9daac9edde4293d2e9fdf30d8b35c04d16a6 and
63bbc250440141b1c51593904fba9bdaa6724280.

I'm seeing issues (e.g. on the GCC torture suite) where
combineBinOpOfExtractToReduceTree is called when the V extensions aren't
enabled and triggers a crash due to RISCVSubtarget::getElen asserting.

I'll aim to follow up with a minimal reproducer. Although it's pretty
obvious how to avoid this crash with some extra gating, there are a few
options as to where that should be inserted so I think it's best to
revert and agree the appropriate fix separately.