[Bug tree-optimization/103458] [12 Regression] ICE in verify_loop_structure, at cfgloop.c:1736 (error: loop with header 4 not in loop tree) since r12-5301-g045206450386bcd7
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103458 Richard Biener changed: What|Removed |Added Status|ASSIGNED|RESOLVED Resolution|--- |FIXED --- Comment #6 from Richard Biener --- Fixed.
[Bug tree-optimization/103458] [12 Regression] ICE in verify_loop_structure, at cfgloop.c:1736 (error: loop with header 4 not in loop tree) since r12-5301-g045206450386bcd7
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103458 --- Comment #5 from CVS Commits --- The master branch has been updated by Richard Biener : https://gcc.gnu.org/g:85e91ad55a69282c1b0e34569836a026a1a954d1 commit r12-5572-g85e91ad55a69282c1b0e34569836a026a1a954d1 Author: Richard Biener Date: Mon Nov 29 09:15:47 2021 +0100 tree-optimization/103458 - avoid creating new loops in CD-DCE When creating forwarders in CD-DCE we have to avoid creating loops where we formerly did not consider those because of abnormal predecessors. At this point simply excuse us when there are any abnormal predecessors. 2021-11-29 Richard Biener PR tree-optimization/103458 * tree-ssa-dce.c (make_forwarders_with_degenerate_phis): Do not create forwarders for blocks with abnormal predecessors. * gcc.dg/torture/pr103458.c: New testcase.
[Bug tree-optimization/103458] [12 Regression] ICE in verify_loop_structure, at cfgloop.c:1736 (error: loop with header 4 not in loop tree) since r12-5301-g045206450386bcd7
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103458 Martin Liška changed: What|Removed |Added Keywords|needs-bisection | Summary|[12 Regression] ICE in |[12 Regression] ICE in |verify_loop_structure, at |verify_loop_structure, at |cfgloop.c:1736 (error: loop |cfgloop.c:1736 (error: loop |with header 4 not in loop |with header 4 not in loop |tree) |tree) since ||r12-5301-g045206450386bcd7 CC||marxin at gcc dot gnu.org --- Comment #4 from Martin Liška --- Started with r12-5301-g045206450386bcd7.
[Bug tree-optimization/103458] [12 Regression] ICE in verify_loop_structure, at cfgloop.c:1736 (error: loop with header 4 not in loop tree)
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103458 --- Comment #3 from Richard Biener --- So the issue is that we have bb3:<-\ <--\ |\ /| | -- | | | bb4: | .ABNORMAL_DISPATCHER at the start of CDDCE and the abnormal predecessor makes us not consider BB3 a loop header. But then we have an opportunity to create a forwarder (we avoid creating them for loop headers but this isn't one ...) which shows the opportunity to represent this CFG as an outer loop with an inner cycle with abnormal edge. CFG cleanup doesn't undo this forwarder because there are virtual PHIs in it. ethread is the pass that introduces this problematic header while this is all inside an irreducible region. In principle handling the abnormal edge in this case would be OK but in general abnormal latches pose a problem since with several loop opts we are facing the need to split/redirect those so relaxing this condition doesn't look feasible (but it creates nicer CFG for this particular testcase).
[Bug tree-optimization/103458] [12 Regression] ICE in verify_loop_structure, at cfgloop.c:1736 (error: loop with header 4 not in loop tree)
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103458 Richard Biener changed: What|Removed |Added Assignee|unassigned at gcc dot gnu.org |rguenth at gcc dot gnu.org Status|NEW |ASSIGNED --- Comment #2 from Richard Biener --- I will have a look.
[Bug tree-optimization/103458] [12 Regression] ICE in verify_loop_structure, at cfgloop.c:1736 (error: loop with header 4 not in loop tree)
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103458 Andrew Pinski changed: What|Removed |Added Ever confirmed|0 |1 Keywords||needs-bisection Last reconfirmed||2021-11-29 Status|UNCONFIRMED |NEW --- Comment #1 from Andrew Pinski --- Confirmed. It looks like a latent bug though.
[Bug tree-optimization/103458] [12 Regression] ICE in verify_loop_structure, at cfgloop.c:1736 (error: loop with header 4 not in loop tree)
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103458 Andrew Pinski changed: What|Removed |Added Target Milestone|--- |12.0
