qCount{Leading,Trailing}ZeroBits: Use __builtin_clzs for 16-bit

If possible.

The BSF/BSR/TZCNT/LZCNT Intel instruction does not exist for 8-bit. And
it's a good idea to use the 32-bit instruction instead of the 16-bit one
for that case, to avoid the Length Changing Prefix (LCP).

GCC doesn't allow us to use __builtin_cl[tz]s unless BMI is active,
while ICC generates the same code either way (Clang understands
__has_builtin).

Change-Id: I8de47ed6c7be4847b99bffff141c91603c7024dc
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@theqtcompany.com>

0 files changed, 0 insertions, 0 deletions