[all-commits] [llvm/llvm-project] 45a334: [RISCV] Generaize reduction tree matching to all i...

[Philip Reames via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 45a334d31cc3a22b1aa28ba463130eb8622abad7
      https://github.com/llvm/llvm-project/commit/45a334d31cc3a22b1aa28ba463130eb8622abad7
  Author: Philip Reames <preames at rivosinc.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:
  -----------
  [RISCV] Generaize reduction tree matching to all integer reductions (#68014) (reapply)

This was reverted in 824251c9b349d859a9169196cd9533c619a715ce exposed by this change in a previous patch.  Fixed in 199cbec987ee68d70611db8e7961b43c3dbad83e.  Original commit message follows.

This builds on the transform introduced in
https://github.com/llvm/llvm-project/pull/67821, and generalizes it for
all integer reduction types.

A couple of notes:
* This will only form smax/smin/umax/umin reductions when zbb is
enabled. Otherwise, we lower the min/max expressions early. I don't care
about this case, and don't plan to address this further.
* This excludes floating point. Floating point introduces concerns about
associativity. I may or may not do a follow up patch for that case.
* The explodevector test change is mildly undesirable from a clarity
perspective. If anyone sees a good way to rewrite that to stablize the
test, please suggest.