[PATCH] D137862: InstCombine: Fold some identities for canonicalize

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added inline comments.


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Comment at: llvm/test/Transforms/InstCombine/canonicalize.ll:284
-; CHECK-NEXT:    [[CANON_X:%.*]] = call float @llvm.canonicalize.f32(float [[X:%.*]])
-; CHECK-NEXT:    [[CMP:%.*]] = fcmp oeq float [[CANON_X]], [[X]]
 ; CHECK-NEXT:    ret i1 [[CMP]]
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spatel wrote:
> This isn't testing what was intended. The operands are canonicalized by complexity before we reach the transform in this patch.
> 
> It needs an extra instruction to create the expected pattern:
> 
> ```
> declare float @gen_f32()
> 
> define i1 @canonicalize_oeq_arg_f32_commute() {
>   %x = call float @gen_f32() ; thwart complexity-based canonicalization
>   %canon.x = call float @llvm.canonicalize.f32(float %x)
>   %cmp = fcmp oeq float %x, %canon.x
>   ret i1 %cmp
> }
> 
> ```
I thought the idea was to rely on the complexity based canonicalization, but I guess that's not good enough 


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D137862/new/

https://reviews.llvm.org/D137862