https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55760
Andrew Pinski changed:
What|Removed |Added
Status|UNCONFIRMED |RESOLVED
Resolution|---
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55760
--- Comment #5 from vincenzo Innocente vincenzo.innocente at cern dot ch
2013-01-08 15:29:18 UTC ---
we just got hit by this great type of code (copysign is unknown to
scientists)
most probably gcc could optimize it for -Ofast to return
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55760
Marc Glisse glisse at gcc dot gnu.org changed:
What|Removed |Added
CC||glisse at
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55760
--- Comment #1 from Richard Biener rguenth at gcc dot gnu.org 2012-12-20
15:52:31 UTC ---
Use -mrecip. It's otherwise not safe for SPEC CPU 2006 which is why it is not
enabled by default for -ffast-math.
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55760
--- Comment #2 from vincenzo Innocente vincenzo.innocente at cern dot ch
2012-12-20 15:55:03 UTC ---
Thanks.
not safe meaning producing incorrect results?
Is it documented?
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55760
--- Comment #3 from Richard Biener rguenth at gcc dot gnu.org 2012-12-20
15:58:55 UTC ---
(In reply to comment #2)
Thanks.
not safe meaning producing incorrect results?
Yes.
Is it documented?
See the documentation for -mrecip:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55760
--- Comment #4 from Dominique d'Humieres dominiq at lps dot ens.fr 2012-12-20
16:07:11 UTC ---
is there any reason why rsqrtss and rcpss are not used for scalar code while
rsqrtps and rcpps are used for loops?
Yep! I don't have the
