https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117922
--- Comment #24 from Richard Biener <rguenth at gcc dot gnu.org> --- (In reply to Paolo Bonzini from comment #22) > Yes, I suggested the MD problem because it did solve gambit performance > issues with fwprop for good, but RTL-SSA is certainly applicable. > > Also, once all RD uses are converted to RTL-SSA it should really be removed > from df.c as a bad idea (and probably also MD since it's unused *sheds a > tear*). Btw, all of UD/DU_CHAINS should be converted. For the testcase at hand all 61152 blocks are in a single big cycle, so optimizing the RD dataflow iteration looks difficult, it's just very cache unfriendly. df_worklist_dataflow_doublequeue: n_basic_blocks 61152 n_edges 48183769 count 378895 ( 6.2) it's the no longer factored computed goto that blows up the number of edges and thus the computational complexity here. See the bug about bb-reorder where we'd suggested to keep the actual CFG representation factored but have the computed goto instruction duplicated.
