http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54146
--- Comment #14 from Steven Bosscher <steven at gcc dot gnu.org> 2012-08-03 08:59:29 UTC --- Created attachment 27930 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=27930 Do not inline_merge_summary if called via flatten_function As I noted in comment #12, the flattening itself is the problem, not the heuristics. I have narrowed this down to inline_merge_summary. With the attached hack, compile time (for only "check<CGAL::Gmpfi>();") drops from 6459s to 1560s. I hi-jacked the unused timevar TV_LOCAL_ALLOC (from pre-IRA days) to measure the time spent in inline_call. Without my hack, this is 4801s, and with the hack it is only 0.37s (!). Do the math: 6459s-4801s=1658s~=1560s. (NB: These timings are all with my stack_vars patch applied as well.) With the hack, the remaining compile time is mostly spent in: tree loop init : 236.16 integrated RA : 215.70 if-conversion : 177.26 (but due to loop_optimizer_init) tree SSA incremental : 154.69 reload : 124.33 I don't understand how inline_merge_summary is supposed to work, so I'm going to leave that one for Richi and Honza.
