------- Additional Comments From kazu at cs dot umass dot edu 2004-12-10 18:53 ------- Subject: Re: [4.0 regression] loop miscompilation at -O1 (-ftree-ch)
Hi Zdenek, > > > or simply use dominated_by_p, which is not too expensive - > > > only a couple of "if" statements, assuming the dominator infomatino is > > > available. > > EDGE_DFS_BACK would have been more efficient. But I don't think it's > > 100% safe right now. > > not that much. Since you do not change cfg in the progress of dominator > optimizations, you should have fast query structure for dominators > up-to-date; i.e. testing whether a basic block dominates other takes only > two comparisons of integers. Right. If we have dominator information available, mark_dfs_back_edges does nothing but duplicates a part of what the dominator information has to offer. (It's not that mark_dfs_back_edges is very flow, but ....) Kazu Hirata -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18694 ------- You are receiving this mail because: ------- You are on the CC list for the bug, or are watching someone who is.
