[all-commits] [llvm/llvm-project] b59c6f: [WebAssembly] Prefer v128.const for constant splats

[Thomas Lively via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: b59c6fcaf3fc8fd4c42daeecf0545e47b37b1aa7
      https://github.com/llvm/llvm-project/commit/b59c6fcaf3fc8fd4c42daeecf0545e47b37b1aa7
  Author: Thomas Lively <tlively at google.com>
  Date:   2020-07-10 (Fri, 10 Jul 2020)

  Changed paths:
    M llvm/lib/Target/WebAssembly/WebAssemblyInstrSIMD.td
    M llvm/test/CodeGen/WebAssembly/simd-arith.ll
    M llvm/test/CodeGen/WebAssembly/simd.ll

  Log Message:
  -----------
  [WebAssembly] Prefer v128.const for constant splats

In BUILD_VECTOR lowering, we used to generally prefer using splats
over v128.const instructions because v128.const has a very large
encoding. However, in d5b7a4e2e8 we switched to preferring consts
because they are expected to be more efficient in engines. This patch
updates the ISel patterns to match this current preference.

Differential Revision: https://reviews.llvm.org/D83581