https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118318
--- Comment #13 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
Thanks for running this through debugger
Breakpoint 2.2, profile_count::operator+= (this=0x7ffff6e7e888, other=...) at
/usr/src/debug/sys-devel/gcc-15.0.9999/gcc-15.0.9999/gcc/profile-count.h:932
932 gcc_checking_assert (compatible_p (other));
(gdb) p other
$1 = (const profile_count &) @0x7fffffff72c0: {
static n_bits = 61,
static max_count = 2305843009213693950,
static uninitialized_count = 2305843009213693951,
m_val = 3694,
m_quality = ADJUSTED
}
is an IPA count. It would be nice to know "p *this", but for compatible_p to
return false it should be function local count.
static void
adjust_clone_incoming_counts (cgraph_node *node,
desc_incoming_count_struct *desc)
{
for (cgraph_edge *cs = node->callers; cs; cs = cs->next_caller)
if (cs->caller->thunk)
{
adjust_clone_incoming_counts (cs->caller, desc);
profile_count sum = profile_count::zero ();
for (cgraph_edge *e = cs->caller->callers; e; e = e->next_caller)
if (e->count.initialized_p ())
sum += e->count.ipa ();
cs->count = cs->count.combine_with_ipa_count (sum);
}
else if (!desc->processed_edges->contains (cs)
&& cs->caller->clone_of == desc->orig)
{
cs->count += desc->count;
if (dump_file)
{
fprintf (dump_file, " Adjusted count of an incoming edge of "
"a clone %s -> %s to ", cs->caller->dump_name (),
cs->callee->dump_name ());
cs->count.dump (dump_file);
fprintf (dump_file, "\n");
}
}
}
Here are two calls to + and it is not clear which one triggers the ICE. However
sum += e->count.ipa (); quite obviously preserves the fact that sum is an IPA
count. So I think it is
cs->count += desc->count
which makes sense to me. dest->count is IPA count
if (cs->count.initialized_p ())
desc->count += cs->count.ipa ();
So I suppose what happens here is that we clone function with no profile
feedback available. This can happen in some cases, with profile mismatches or
with comdat merging.
Martin, I think this is yours code, but I would say that if desc is IPA count
of 3694 while cs->count is locally estimated, we don't really have way to add
them together, so I would just skip the adjustment on !cs->count.ipa_p ()
However it is not clear to me how desc can be something non-zero in this case?
>From where the number comes?
It is possible that we scaled down the profile from non-zero to 0 which makes
us to downgrade IPA profile to non-IPA, but in that case the updating code
attempts to do something fisly making call site within function with 0
invocations to have non-zero count.
Honza
