[PATCH] D87884: [CostModel][X86] add CostModel for SK_Select(v8f64, v8i64, v16f32, v16i32, v32i16, v64i8)

[Bing Yu via Phabricator via llvm-commits]

yubing added a comment.

In D87884#2286958 <https://reviews.llvm.org/D87884#2286958>, @craig.topper wrote:

> In D87884#2286918 <https://reviews.llvm.org/D87884#2286918>, @yubing wrote:
>
>> With avx512f, the cost SK_Select(v32i16 or v64i8) shoulde be 3(vmovdqa64 + vpternlogq)
>
> The moves probably don't really count since they can be eliminated during register renaming. So only the vpternlog executes.

Eh, Craig, why it has relationship with register renaming? I thought, vternlog's third operand should be provided by a vmovdqa64.
Besides, we can observe the following asm for v32i16's SK_Select:

  vmovdqa64       .LCPI0_0(%rip), %zmm0   # zmm0 = [0,0,0,65535,65535,65535,65535,65535,65535,65535,65535,65535,65535,65535,65535,65535,65535,65535,65535,65535,65535,65535,65535,65535,65535,65535,65535,65535,65535,65535,65535,65535]
  vpternlogq      $202, 144(%rbp), %zmm4, %zmm0




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