[Bug target/70708] Suboptimal code generated when using _mm_set_sd (X64)

glisse at gcc dot gnu.org gcc-bugzilla@gcc.gnu.org
Mon Apr 18 20:06:00 GMT 2016


https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70708

--- Comment #14 from Marc Glisse <glisse at gcc dot gnu.org> ---
(In reply to H.J. Lu from comment #12)
> (In reply to Marc Glisse from comment #11)
> > As I told you in the other PR, movq is *NOT* what the PRs are asking for, it
> 
> See the subject of this PR.

1) I know for certain this is not what PR68211 (a bug you closed as a
duplicate) was asking for, since I filed that one.

2) If you read the summary, the optimal code Petr is asking for here is no move
at all, i.e. the same clang is generating. movq is still suboptimal here.

While I really appreciate the quick improvement on using movq, I don't
understand why you are so set on closing these PRs... Intel's intrinsics and
their gcc implementation make it hard to write scalar code without overhead,
that seems a relevant concern to me.


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