cogl-bitmask: Use ffsl to speedup bitmask iteration

Instead of testing each bit when iterating a bitmask, we can use ffsl
to skip over unset bits in single instruction. That way it will scale
by the number of bits set, not the total number of bits.

ffsl is a non-standard function which glibc only provides by defining
GNUC_SOURCE. However if we are compiling with GCC we can avoid that
mess and just use the equivalent builtin. When not compiling for GCC
it will fall back to _cogl_util_ffs if the size of ints and longs are
the same (which is the case on i686). Otherwise it fallbacks to a slow
function implementation.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

0 files changed, 0 insertions, 0 deletions