[all-commits] [llvm/llvm-project] 4c8cf9: [RISCV] Use the first element of source as the sta...

[Yeting Kuo via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 4c8cf9206735b9b3cd2671b53e505d5f15578773
      https://github.com/llvm/llvm-project/commit/4c8cf9206735b9b3cd2671b53e505d5f15578773
  Author: Yeting Kuo <yeting.kuo at sifive.com>
  Date:   2023-08-01 (Tue, 01 Aug 2023)

  Changed paths:
    M llvm/lib/Target/RISCV/RISCVISelLowering.cpp
    M llvm/test/CodeGen/RISCV/double_reduct.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-reduction-fp.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-reduction-int-vp.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-reduction-int.ll
    M llvm/test/CodeGen/RISCV/rvv/fold-binary-reduce.ll
    M llvm/test/CodeGen/RISCV/rvv/vreductions-fp-sdnode.ll
    M llvm/test/CodeGen/RISCV/rvv/vreductions-int-vp.ll
    M llvm/test/CodeGen/RISCV/rvv/vreductions-int.ll

  Log Message:
  -----------
  [RISCV] Use the first element of source as the start value of reduction.

Previously when llvm.reduce.* lowered, riscv backend created scalar vector with
netural element as start value. For llvm.reduce.and/or/min/max/fmax/fmin, we
could use the first element of source as the start value. It's benefit for RVV
since we could just use source vector as start vector.

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D155929