https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105618
--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
There was quite some massaging in handling of PHI uses, notably we now have
/* For PHI nodes the block we know sth about is the incoming
block
with the use. */
if (gimple_code (use_stmt) == GIMPLE_PHI)
{
/* In case the PHI node post-dominates the current insert
location we can disregard it. But make sure it is not
dominating it as well as can happen in a CFG cycle. */
if (commondom != bb
&& !dominated_by_p (CDI_DOMINATORS, commondom, bb)
&& dominated_by_p (CDI_POST_DOMINATORS, commondom, bb)
/* If the blocks are possibly within the same irreducible
cycle the above check breaks down. */
&& !((bb->flags & commondom->flags & BB_IRREDUCIBLE_LOOP)
&& bb->loop_father == commondom->loop_father)
&& !((commondom->flags & BB_IRREDUCIBLE_LOOP)
&& flow_loop_nested_p (commondom->loop_father,
bb->loop_father))
&& !((bb->flags & BB_IRREDUCIBLE_LOOP)
&& flow_loop_nested_p (bb->loop_father,
commondom->loop_father)))
continue;
and already the first !dominated_by_p (CDI_DOMINATORS, commondom, bb) check
makes us not consider the sink opportunity. That was introduced as part
of the fix for PR97330.
