[all-commits] [llvm/llvm-project] 0353c2: [InstCombine] fold shuffles with FP<->Int cast ope...

[Sanjay Patel via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 0353c2c996c5863463c356de97c9852f9330ed11
      https://github.com/llvm/llvm-project/commit/0353c2c996c5863463c356de97c9852f9330ed11
  Author: Sanjay Patel <spatel at rotateright.com>
  Date:   2022-05-10 (Tue, 10 May 2022)

  Changed paths:
    M llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
    M llvm/test/Transforms/InstCombine/vec_shuffle.ll

  Log Message:
  -----------
  [InstCombine] fold shuffles with FP<->Int cast operands

shuffle (cast X), (cast Y), Mask --> cast (shuffle X, Y, Mask)

This is similar to a recent transform with fneg ( b331a7ebc1e0 ),
but this is intentionally the most conservative first step to
try to avoid regressions in codegen. There are several
restrictions that could be removed as follow-up enhancements.

Note that a cast with a unary shuffle is currently canonicalized
in the other direction (shuffle after cast - D103038 ). We might
want to invert that to be consistent with this patch.