On May 30, 2015 12:24:30 AM GMT+02:00, Phil Blundell <[email protected]> wrote: >On Fri, 2015-05-29 at 16:28 +0100, Paul Eggleton wrote: >> Just for background, the reason I disabled the textrel check for x86 >in >> libav.inc was that I was able to determine based on quick research >that >> upstream deliberately doesn't enable -fPIC for x86 (32-bit) because >apparently >> it doesn't really work there. I honestly didn't check what the >situation was >> on 32-bit ARM; I probably should have done that at the time. > >PIC is particularly problematic on x86 because it ties up %ebx. This >represents 25% of the available general purpose registers which can >cause a measurable performance loss because of increased spilling, and
Note that the situation improved with gcc-5 for some cases though. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54232 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47602 https://software.intel.com/en-us/blogs/2014/12/26/new-optimizations-for-x86-in-upcoming-gcc-50-32bit-pic-mode Cheers, -- _______________________________________________ Openembedded-core mailing list [email protected] http://lists.openembedded.org/mailman/listinfo/openembedded-core
