[Bug lto/82229] GCC7's LTO underperforms compared to GCC6

[krzysio.kurek at wp dot pl]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82229

--- Comment #22 from krzysio.kurek at wp dot pl ---
I'm sorry but profiling doesn't seem to be well documented, what tools should I
use to generate a profiling log?