http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49786
Ian Lance Taylor <ian at airs dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed| |2011.07.20 22:03:04
AssignedTo|unassigned at gcc dot |jamborm at gcc dot gnu.org
|gnu.org |
Ever Confirmed|0 |1
--- Comment #12 from Ian Lance Taylor <ian at airs dot com> 2011-07-20 22:03:04
UTC ---
I was able to recreate the problem. The count is going negative at line 1926
of ipa-cp.c, the first line setting cs->count here:
for (cs = new_node->callees; cs ; cs = cs->next_callee)
if (cs->frequency)
cs->count = cs->count * new_sum / orig_node_count;
else
cs->count = 0;
In the test case, cs->count, new_sum, and orig_node_count all == 3870557758.
Computing 3870557758 * 3870557758 overflows to a negative number. Dividing by
3870557758 leaves the number still negative. This then leads to the failure.
For reference, profile_info->sum_max == 2619109064700.
I don't know if these numbers are plausible.
I think that this code probably needs to be written along the lines of
scale_bbs_frequencies_gcov_type. I will leave this for Martin.
