[cairo] SSE support in pixman

[Frederic Plourde]

 Hi Soren!

I'm currently looking at mmx/sse support in pixman. My upcoming goals are :
1- Make win32 platforms compile MMX code
2- Extend/Add MMX optimizations in pixman
3- SSE optims as well.

I'm writing to you, as I saw your major contributions to MMX code :-)
However, I saw this comment pixman/configure.ac :

"dnl GCC 4.2 when compiling with -msse will generate SSE instructions
dnl on its own.  This means anything compiled with -mss can only be
dnl run after a runtime check for SSE.  Unfortunately, since we still
dnl need to support MMX-but-not-SSE (such as the OLPC), this means we
dnl can only use SSE when compiling for x86-64 (where SSE is always
dnl supported)."

... and I'm wondering...my question is :

Isn't there anything we can do to support SSE...even on _x86_ ? How about
enhancing "detectCPUFeatures(...) to detect specific non_SSE platforms such as
the OLPC and then branch accordingly ? You are way more experienced than I am
with pixman intrinsics... I was wondering if this sounds possible to you ;-)

thanks !

-fred-