https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111397
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Assignee|unassigned at gcc dot gnu.org |rguenth at gcc dot
gnu.org
Last reconfirmed| |2023-09-13
Status|UNCONFIRMED |ASSIGNED
Ever confirmed|0 |1
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #1)
> Looks loop copy header change which allowed the warning not to happen.
>
> The warning is about the argument of test_setjmpex. Because GCC does not
> realize __builtin_frame_address cannot jump to the test_setjmpex ...
>
> In the case of GCC 12-13, the copy of the loop header happens during
> thread-full rather than earlier and inserts:
> _4(ab) = _11(D);
>
> Which is what is warned about.
> _11(D) does not get proped into the phi ...
We can't propagate because
/* Similarly if DEST flows in from an abnormal edge then the copy cannot be
propagated. If we know we do not propagate into a PHI argument this
does not apply. */
else if (!dest_not_phi_arg_p
&& TREE_CODE (dest) == SSA_NAME
&& SSA_NAME_OCCURS_IN_ABNORMAL_PHI (dest))
return false;
that's still not fine-grained enough - the case we cannot propagate is
when we propagate into a PHI argument for an abnormal edge.
The diagnostic doesn't happen on trunk, I still have a patch doing the
propagation.
