[all-commits] [llvm/llvm-project] 9fb946: [InstCombine] add tests for rotate/funnel; NFC

[RotateRight via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 9fb946f1a8dd99ff5a77748114889422f57967b8
      https://github.com/llvm/llvm-project/commit/9fb946f1a8dd99ff5a77748114889422f57967b8
  Author: Sanjay Patel <spatel at rotateright.com>
  Date:   2021-04-28 (Wed, 28 Apr 2021)

  Changed paths:
    M llvm/test/Transforms/InstCombine/funnel.ll
    M llvm/test/Transforms/InstCombine/rotate.ll

  Log Message:
  -----------
  [InstCombine] add tests for rotate/funnel; NFC


  Commit: abd7529625a73f405e40a63dcc446c41d51a219e
      https://github.com/llvm/llvm-project/commit/abd7529625a73f405e40a63dcc446c41d51a219e
  Author: Sanjay Patel <spatel at rotateright.com>
  Date:   2021-04-28 (Wed, 28 Apr 2021)

  Changed paths:
    M llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
    M llvm/test/Transforms/InstCombine/funnel.ll
    M llvm/test/Transforms/InstCombine/rotate.ll

  Log Message:
  -----------
  [InstCombine] relax masking requirement for truncated funnel/rotate match

I was investigating a seemingly unrelated improvement in demanded
bits for shift-left, but that caused regressions on these tests
because we were able to look through/eliminate the mask.

https://alive2.llvm.org/ce/z/Ztdr22

  define i8 @src(i32 %x, i32 %y, i32 %shift) {
  %and = and i32 %shift, 3
  %conv = and i32 %x, 255
  %shr = lshr i32 %conv, %and
  %sub = sub i32 8, %and
  %shl = shl i32 %y, %sub
  %or = or i32 %shr, %shl
  %conv2 = trunc i32 %or to i8
  ret i8 %conv2
  }

  define i8 @tgt(i32 %x, i32 %y, i32 %shift) {
  %x8 = trunc i32 %x to i8
  %y8 = trunc i32 %y to i8
  %shift8 = trunc i32 %shift to i8
  %and = and i8 %shift8, 3
  %conv2 = call i8 @llvm.fshr.i8(i8 %y8, i8 %x8, i8 %and)
  ret i8 %conv2
  }

  declare i8 @llvm.fshr.i8(i8,i8,i8)


Compare: https://github.com/llvm/llvm-project/compare/4d41810cf679...abd7529625a7