------- Comment #42 from pinskia at gcc dot gnu dot org 2007-01-22 02:27
-------
(In reply to comment #41)
> So I tested some C++ vector code using at, in a desperate attempt to find ANY
> case where this so called "optimization" actually produces faster code.
Try looking at real code instead of benchmarks :). I bet the reason why ICC
beats GCC is not because GCC cannot do a good job but ICC's standard template
library is implemented slightly different.
> $ gcc -O3 -o vector2 vector2.C
> $ ./vector2
> 69859 cycles
> $ gcc -O3 -o vector2 vector2.C -fwrapv
> $ ./vector2
> 69606 cycles
I bet this is all to do with cache and not really anything do with the
optimization.
>Why don't you get over the fact that this was a really bad decision,
> undo it, and we will all live happily ever after.
Only a few people think it is a bad decision. Anyways nothing said in this bug
will change anything, you should do what Tom Tromey said in comment #40 and
what I mentioned in comment #22, and write to the gcc@gcc.gnu.org mailing list
after reading all previous decussion on this matter. Since it sounds like you
only care about the security code which was incorrectly written.
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |WONTFIX
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30475
