https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102385
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Status|UNCONFIRMED |NEW
CC| |rguenth at gcc dot gnu.org,
| |rsandifo at gcc dot gnu.org
Summary|ICE: in single_pred_edge, |[12 Regression] ICE: in
|at basic-block.h:350 under |single_pred_edge, at
|"-O2 -fno-toplevel-reorder |basic-block.h:350 under
|-fno-tree-ch -fno-tree-dce |"-O2 -fno-toplevel-reorder
|-fno-tree-dominator-opts |-fno-tree-ch -fno-tree-dce
|-fno-tree-dse |-fno-tree-dominator-opts
|-fno-tree-loop-ivcanon |-fno-tree-dse
|-fpredictive-commoning" |-fno-tree-loop-ivcanon
| |-fpredictive-commoning"
Keywords| |ice-on-valid-code,
| |needs-bisection, wrong-code
Last reconfirmed| |2021-09-17
Target Milestone|--- |12.0
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Huh, the code is odd:
basic_block exit_bb = single_pred (loop->latch);
new_exit = find_edge (exit_bb, rest);
new_exit->probability = profile_probability::always ()
.apply_scale (1, new_est_niter + 1);
but here we have a diamond after the block that exits the loop and thus
neither a single predecessor of the latch nor would that be something
resembling an exit block. It looks like the code might have wanted
to use single_pred (rest) here plus eventually splitting the exit
edge in case it didn't have a single predecessor.
Richard, you refactored this, so likely caused this.
