HWCAP is method to determine cpu features, not selection mechanism.

[Szabolcs Nagy]

On 10/06/15 14:35, Adhemerval Zanella wrote:
> I agree that adding an API to modify the current hwcap is not a good
> approach. However the cost you are assuming here are *very* x86 biased,
> where you have only on instruction (movl <variable>(%rip), %<destiny>) 
> to load an external variable defined in a shared library, where for
> powerpc it is more costly:

debian codesearch found 4 references to __builtin_cpu_supports
all seem to avoid using it repeatedly.

multiversioning dispatch only happens at startup (for a small
number of functions according to existing practice).

so why is hwcap expected to be used in hot loops?