[all-commits] [llvm/llvm-project] 2baa1d: [RISCV] Add basic support for matching shuffles to...

[Craig Topper via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 2baa1dffd1fb03c2a88d7116252aca76a29d0026
      https://github.com/llvm/llvm-project/commit/2baa1dffd1fb03c2a88d7116252aca76a29d0026
  Author: Craig Topper <craig.topper at sifive.com>
  Date:   2022-01-14 (Fri, 14 Jan 2022)

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

  Log Message:
  -----------
  [RISCV] Add basic support for matching shuffles to vslidedown.vi.

Specifically the unary shuffle case where the elements being
shifted in are undef. This handles the shuffles produce by expanding
llvm.reduce.mul.

I did not reduce the VL which would increase the number of vsetvlis,
but may improve the execution speed. We'd also want to narrow the
multiplies so we could share vsetvlis between the vslidedown.vi and
the next multiply.

Reviewed By: frasercrmck

Differential Revision: https://reviews.llvm.org/D117239