[all-commits] [llvm/llvm-project] b18b2a: [RISCV] Don't use VLMAX for start value splat in r...

[Craig Topper via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: b18b2a01ef040698e8e6a2400d55a5c290f097b9
      https://github.com/llvm/llvm-project/commit/b18b2a01ef040698e8e6a2400d55a5c290f097b9
  Author: Craig Topper <craig.topper at sifive.com>
  Date:   2021-12-13 (Mon, 13 Dec 2021)

  Changed paths:
    M llvm/lib/Target/RISCV/RISCVISelLowering.cpp
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-reduction-fp-vp.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/vreductions-fp-sdnode.ll
    M llvm/test/CodeGen/RISCV/rvv/vreductions-fp-vp.ll
    M llvm/test/CodeGen/RISCV/rvv/vreductions-int-rv32.ll
    M llvm/test/CodeGen/RISCV/rvv/vreductions-int-rv64.ll
    M llvm/test/CodeGen/RISCV/rvv/vreductions-int-vp.ll

  Log Message:
  -----------
  [RISCV] Don't use VLMAX for start value splat in reduction lowering.

The reduction instructions only reads the first element. The
execution time for a splat may take longer with a larger VL.
We should use the smallest VL we can.

Reviewed By: frasercrmck, HsiangKai

Differential Revision: https://reviews.llvm.org/D115536