[FFmpeg-devel] forcing ints to be 64 bits, possible new FATE client idea

[Ganesh Ajjanagadde]

Hi all,

It is known that there exist at least certain parts of the codebase
that do not work correctly if ints are 64 bits. One of them I noticed
was in avutil/intmath.h: ff_ctz_c does not compute the right thing if
int is 64 bits. This is true both before and after the De-Bruijn
optimization.

A more interesting (and serious) question is whether FATE is broken if
int's are 64 bits. I did some digging, and found the following from
"The Definitive Guide to GCC" - On GCC prior to 4.x, there was a flag
-mint64, documented as follows (see e.g
https://gcc.gnu.org/onlinedocs/gcc-3.4.6/gcc.pdf):
"Force int and long types to be 64 bits wide. See -mlong32 for an
explanation of the default and the way that the pointer size is
determined".

This should be helpful in setting up a FATE client to test (and
possibly fix) bad code that assumed int = 32 bits. I myself can't
easily run such an outdated GCC, but I noticed a bunch of clients
running GCC < 4.0 where this may be set up.

Regards,
Ganesh