https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103990
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed| |2022-01-12
Ever confirmed|0 |1
Assignee|unassigned at gcc dot gnu.org |rguenth at gcc dot
gnu.org
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
OK, so the only effect I can think of is that simple_dce_from_worklist can end
up removing the last stmt in a BB and thus _eventually_ expose BB merging CFG
cleanup opportunities. I also notice that while tail_merge_optimize altered
todo by clearing TODO_cleanup_cfg, PRE just did (and still does)
- todo |= tail_merge_optimize (todo);
+ todo |= tail_merge_optimize (todo, need_crit_edge_split);
so it would have retained TODO_cleanup_cfg, something we now do not. The
code is all somewhat of a mess due to the embedded tail-merge and I tried
to do as little changes as possible this late in the cycle.
I'll try to reproduce and see if keeping TODO_cleanup_cfg around helps.
