http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56490
--- Comment #5 from davidxl <xinliangli at gmail dot com> 2013-03-08 16:21:13 UTC --- (In reply to comment #4) > Clearly the limiting is bougs ... the issue is with large fanout BBs > we recurse in compute_control_dep_chain which leads to exponential > complexity. Limiting that to 8^5 isn't really a fix ... (yes, you > can call that O(1)). > > compute_control_dep_chain is called 65 million times(!) for the testcase > after the patch. > > There has to be a better algorithmic way of implementing this. > > IMHO still not fixed in 4.8. Right. However for on demand computation like this, limiting is still needed. For this particular case, limiting the depth to 3 (or may be smaller) won't cause any regressions.
