On Fri, 15 Mar 2019, Jakub Jelinek wrote: > On Fri, Mar 15, 2019 at 09:46:33AM +0100, Richard Biener wrote: > > On Fri, 15 Mar 2019, Jakub Jelinek wrote: > > > > > On Fri, Mar 15, 2019 at 09:22:26AM +0100, Richard Biener wrote: > > > > That said, I think we can go with my patch for GCC 9 and defer a more > > > > complete and elaborate solution to GCC 10 (where I'd still prefer > > > > sth simple). > > > > > > > > What do you think? > > > > > > Ok. gimple_purge_dead_abnormal_call_edges after all isn't that expensive, > > > it just walks over all successor edges of a bb. > > > Right now gimple_purge_all_dead_abnormal_call_edges is only called by > > > sccvn on specific bbs that do need ab cleanup, tree-inline.c calls > > > gimple_purge_dead_abnormal_call_edges only if it is inlining a call at the > > > end of a bb and tree-cfg.c calls it for const/pure calls. > > > > > > In that last case, I wonder if we actually shouldn't do following, because > > > it makes no sense to call it for each constant/pure call in a bb when all > > > we > > > care about is whether it is the last stmt that is a pure/const call. > > > > Sure. Though I think with us now having gimple_call_set_ctrl_altering > > execute_fixup_cfg can be stripped down considerably - possibly simply > > leaving most parts to CFG cleanup. The noreturn fixup is still > > required if a call becomes known to not return (CFG cleanup only > > looks at the last stmt), but gimple_purge_dead_abnormal_call_edges can > > be completely elided IMHO (just schedule CFG cleanup). > > The CFG cleanup never calls gimple_purge_dead_abnormal_call_edges though.
Indeed. I guess it could do that where it calls gimple_purge_dead_eh_edges (cleanup_control_flow_bb). > Do we ever update gimple_call_ctrl_altering_p flag if something changes? Yes, CFG cleanup does this and if fixup_cfg needs to live it could do that as well (it calls fixup_noreturn_call which updates it for example). Richard. > Jakub > -- Richard Biener <rguent...@suse.de> SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nuernberg)
