Hi all, I'm trying to use g++ to compile a function with optimization O2 except for one function I want at O3. I'm not having any luck with __attribute__ or #pragma. I am using GCC version 4.7.2. With __attribute__ I am getting a warning that the directive was ignored, and with #pragma I am simply not seeing the speedup expected. Here's what I've tried. bool* getStreamBool(uint64_t num) __attribute__ ((optimize("-O3"))) {...} And #pragma GCC push_options #pragma GCC optimize ("O3") bool* getStreambool(uint64_t num) {...} #pragma GCC pop_options Thanks, Kirk