Re: [PATCH, libstdc++, complex] complex multiplication algorithm improved

[Richard Guenther <richard dot guenther at gmail dot com>]

On Wed, Sep 15, 2010 at 5:50 PM, Gabriel Dos Reis <gdr@cs.tamu.edu> wrote:
> "Joseph S. Myers" <joseph@codesourcery.com> writes:
>
> | On Wed, 15 Sep 2010, Richard Guenther wrote:
> |
> | > easier for the original variant (that is actually something
> | > one might consider changing - manually use fma
> | > intrinsics when the CPU supports that).
> |
> | I'd certainly encourage adding support for RTL patterns for __builtin_fma
> | (and stopping using RTL for non-fused operations to describe fma
> | instructions, doing contracting separately in a way that can be restricted
> | when desired to cases where the source language permits it).
>
> strongly supported.

Of course CPUs tend to support a variety of variants with respect to
negation of operands ... quite a mess to enumerate them all.
Can we somehow provide a container around an rtx that prevents
splitting the fma in pieces?

Richard.

> -- Gaby
>