[RFC] Add FMA support to sparc backend

[Eric Botcazou]

> Second, like rs6000 the sparc negate fused multiply instructions
> negate the full result, not the multiply result.  So we cannot use
> those instructions for the fnmadf4/fnmsdf4/fnmasf4/fnmssf4 patterns.
> Since rs6000 provides patterns for such negate operations (presumably
> just in case the combiner creates a match) I have done so for sparc
> as well.

OK, this makes sense indeed.

> For now my plan is to turn these fused multiply instructions on if you
> ask to compile targetting a cpu that supports them.

> I'll write a suitable changelog etc. once everything is finalized, this
> patch posting is just to elicit feedback.

What's the story with TFmode for FMA?

Thanks for working on this!

-- 
Eric Botcazou