https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93264
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2020-01-16
CC| |hubicka at gcc dot gnu.org,
| |jakub at gcc dot gnu.org
Ever confirmed|0 |1
--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
It tries to redirect a crossing jump from cold to hot partition to a new bb
that is in cold partition.
cfg_layout_redirect_edge_and_branch has code to handle this case, but only if
the
branch is simplejump:
4429 if (e->flags & EDGE_CROSSING
4430 && BB_PARTITION (e->src) == BB_PARTITION (dest)
4431 && simplejump_p (BB_END (src)))
4432 {
4433 if (dump_file)
4434 fprintf (dump_file,
4435 "Removing crossing jump while redirecting edge form %i
to %i\n",
4436 e->src->index, dest->index);
4437 delete_insn (BB_END (src));
4438 remove_barriers_from_footer (src);
4439 e->flags |= EDGE_FALLTHRU;
4440 }
which is not the case here:
(insn 577 350 578 27 (set (reg:DI 309)
(high:DI (label_ref:DI 220))) "pr71550.c":19:20 -1
(insn_list:REG_LABEL_OPERAND 220 (nil)))
(insn 578 577 579 27 (set (reg:DI 308)
(lo_sum:DI (reg:DI 309)
(label_ref:DI 220))) "pr71550.c":19:20 -1
(insn_list:REG_LABEL_OPERAND 220 (expr_list:REG_EQUAL (label_ref:DI 220)
(nil))))
(jump_insn/j 579 578 220 27 (set (pc)
(reg:DI 308)) "pr71550.c":19:20 -1
(nil)
-> 220)
The generic code really doesn't know what it should remove to replace it with
the fallthru edge.
So, I'd say something in the caller or a few callers up should have punted on
it before, but no idea what.
