https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83610
--- Comment #3 from Daniel Fruzynski <bugzi...@poradnik-webmastera.com> --- Created attachment 42980 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=42980&action=edit Benchmark Here is benchmark for this case. With unlikely() execution time decreases from 20.5sec to 20.3sec - about 1%. For my real app change it was a bit more than 2%. Thanks for information about this parameter, I will give it a try. So far I noticed that gcc uses CMOV when values are stored in registers. When they are in memory as a class fields, it generates code with branches. I am still playing with this code, so maybe I will need it later. BTW, what do you thing about adding 3rd param to __builtin_expect, which will specify probability? It may be helpful in cases like mine.
