http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57571
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |jakub at gcc dot gnu.org
--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Have you actually measured any slowdown, or you just think that rep movsd must
be 8 times faster than rep movsb?
If you look at
http://www.intel.com/content/dam/doc/manual/64-ia-32-architectures-optimization-manual.pdf
look at 3-91 there, IvyBridge CPUs and higher are supposed to have ERMSB
feature where rep movsb is always suppoed to be faster than rep movsd + movsb.
