[OE-core] [PATCH 4/5] libav: upgrade to 9.18

[Bernhard Reutner-Fischer]

On May 30, 2015 12:24:30 AM GMT+02:00, Phil Blundell <pb at pbcl.net> 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,