[Ffmpeg-devel] RUNTIME_CPUDETECT broken on PPC due to -maltivec
Fri Mar 9 19:31:39 CET 2007
Sam Hocevar wrote:
> FFmpeg's runtime AltiVec detection doesn't work, the library crashes
> in random places on a G3 machine.
> Contrary to common belief, when using -maltivec gcc *can* generate
> AltiVec code in unexpected, non-vector-using places. Whether this is the
> correct behaviour or not, I don't know, but it's gcc's behaviour. And
> without -maltivec, there is no way to include <altivec.h> and use vector
Doesn't the same apply for x86 or other arches ?
According to my gcc man :
These options will enable GCC to use these extended instructions in
generated code, even without -mfpmath=sse. Applications which per-
form runtime CPU detection must compile separate files for each
supported architecture, using the appropriate flags. In particu-
lar, the file containing the CPU detection code should be compiled
without these options.
More information about the ffmpeg-devel