* Marc Glisse:
> On Mon, 7 Jan 2019, Konstantin Kharlamov wrote:
>
>> In most projects a definite pattern that's unlikely to be executed
>> is a PRINT_ERR macro which is basically a wrapper around fprintf()
>> call. E.g.
>>
>> if (some_error) {
>> PRINT_ERR("ERR");
>> // do cleanup
>> return;
>> }
>>
>> I wonder, is there a way to hint GCC that, whenever that code
>> appears, whatever branch was prior to that is unlikely to be
>> executed?
>
> Make PRINT_ERR a function with __attribute__((cold)).
But this does something completely differently. On some targets, it
produces unbearably slow code because GCC expects the code to never run
in practice. __builtin_expect does not have this effect.
Thanks,
Florian
