[Bug middle-end/19706] Recognize common Fortran usages of copysign.

["tnfchris at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=19706

Tamar Christina <tnfchris at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |tnfchris at gcc dot gnu.org

--- Comment #5 from Tamar Christina <tnfchris at gcc dot gnu.org> ---
(In reply to Ramana Radhakrishnan from comment #4)
> 
> I would have put these testcases into gcc.dg/vect and added a
> target_supports_vect_xorsign so that other targets had a fighting chance of
> catching such changes.

Except for the execution tests, the rest are way too AArch64 specific as they
scan the generated assembly. I could however write a generic mid-end one I
think to check for the internal function.

> 
> Is this pattern relevant to AArch32 for instance ? If so I'd like to add
> those patterns there for bonus points ...  

Yeah AArch32 would benefit some as well. So fair enough, I'll add it there too.

> 
> I suspect the drotg testcase is fixed up by this . If so this bug should
> then be closed out as the mid-end has support for it. I'm not clear if
> slasv2.f is worth  looking at further as another example.

Indeed this does fix drotg for targets that implement the optab, the slasv2 is
interesting as it does point out one issue which is combining XORSIGN and
COPYSIGN  calls in the same chain produces suboptimal code.