[llvm] [X86] Fold OR of constant splats into GF2P8AFFINEQB (PR #194330)

[via llvm-commits]

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ParkHanbum wrote:

I've try to show asm commemt, but it is not visible. how did I can show them?
```
$ bin/llc -mtriple=x86_64-unknown-linux-gnu -mattr=+avx,+gfni < t.ll
        .att_syntax
        .file   "<stdin>"
        .section        .rodata.cst16,"aM", at progbits,16
        .p2align        4, 0x0                          # -- Begin function test_affine_or_fold_v16i8
.LCPI0_0:
        .byte   1                               # 0x1
        .byte   2                               # 0x2
        .byte   4                               # 0x4
        .byte   8                               # 0x8
        .byte   0                               # 0x0
        .byte   0                               # 0x0
        .byte   0                               # 0x0
        .byte   0                               # 0x0
        .byte   1                               # 0x1
        .byte   2                               # 0x2
        .byte   4                               # 0x4
        .byte   8                               # 0x8
        .byte   0                               # 0x0
        .byte   0                               # 0x0
        .byte   0                               # 0x0
        .byte   0                               # 0x0
        .text
        .globl  test_affine_or_fold_v16i8
        .p2align        4
        .type   test_affine_or_fold_v16i8, at function
test_affine_or_fold_v16i8:              # @test_affine_or_fold_v16i8
        .cfi_startproc
# %bb.0:                                # %entry
        vgf2p8affineqb  $15, .LCPI0_0(%rip), %xmm0, %xmm0
        retq
.Lfunc_end0:
        .size   test_affine_or_fold_v16i8, .Lfunc_end0-test_affine_or_fold_v16i8
        .cfi_endproc
                                        # -- End function
        .section        ".note.GNU-stack","", at progbits
```


https://github.com/llvm/llvm-project/pull/194330