Ryan Schmidt <pixman-20...@ryandesign.com> writes: > On May 30, 2012, at 20:33, Søren Sandmann wrote: > >> Maybe the difference is that you are using "-O0" where Ryan is using >> "-O2". The "K" constraint requires the argument to be compile-time >> constant, which it is, but clang may not be able to see that without >> optimization. > > Confirmed: If I set configure.optflags=-O0 on the command line, the > configure check whether to use MMX intrinsics correctly says "no" and > pixman builds. But with -O1 or the default -O2 it says "yes" and the > build subsequently fails. > > Will using -O0 be detrimental to performance, or is that a viable > workaround we could put into the MacPorts portfile?
Using -O0 will be catastrophic for performance. Pixman relies heavily on compiler optimizations. > Someone else in our ticket commented that we could use the > --disable-mmx configure arg. Would that be better or worse? Much better. Turning it off should have essentially no effect on performance on typical x86 systems (it might actually be a tiny win), including all x86 Macintoshes ever produced. Søren _______________________________________________ Pixman mailing list Pixman@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/pixman