[PATCH] D48467: [X86] Recognize an fnma in the presence of an intervening shuffle.

[Easwaran Raman via llvm-commits]

No, this doesn't deal with this. Should I start from the negate and push it
down if it is transitively used by fma?

On Fri, Jun 22, 2018 at 9:38 AM, Sanjay Patel via Phabricator <
reviews at reviews.llvm.org> wrote:

> spatel added a comment.
>
> Does this patch deal with the case if we negate the scalar before doing
> the splat?
>
> define <8 x float> @test7(float %a, <8 x float> %b, <8 x float> %c)  {
>
>   %t0 = fsub float -0.0, %a
>   %t1 = insertelement <8 x float> undef, float %t0, i32 0
>   %t2 = shufflevector <8 x float> %t1, <8 x float> undef, <8 x i32>
> zeroinitializer
>   %t3 = tail call <8 x float> @llvm.fma.v8f32(<8 x float> %t2, <8 x float>
> %b, <8 x float> %c)
>   ret <8 x float> %t3
>
> }
>
> That transform was suggested as a canonicalization in:
> https://bugs.llvm.org/show_bug.cgi?id=37463
>
>
> Repository:
>   rL LLVM
>
> https://reviews.llvm.org/D48467
>
>
>
>
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