Does compilation with -g result in slower code?

Question

I am using a package that is compiled using gcc -O3 -g.

Since some function calls to that code are the slowest part of my program I am wondering if the -g could be the culprit? Or should it not matter in terms of runtime?

Answer 1

Since -O3 implies aggressive inlining, and -g implies avoiding inlining so that the debugger can have function addresses, those options are somewhat at odds. Nevertheless in general -O3 wins, and aside from a somewhat larger binary -- and the minor speed effects that might come from paging or nonlocality -- it should not make much of a difference.