https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103168
--- Comment #12 from hubicka at kam dot mff.cuni.cz ---
> unsigned p;
> unsigned __attribute__((noinline)) test (void)
> {
> return p;
> }
>
> modref analyzing 'test' (ipa=0) (pure)
> - Analyzing load: p
> - Recording base_set=0 ref_set=0
> - modref done with result: tracked.
Modref does not record accesses to global vars as known baes and just as
accesses relative to MODREF_UNKONWN_PARM (since ipa-reference does this)
So only useful info it collect from loads/stores is the alias set and
here it is 0 (why?).
Then it drops the summary as useless since function is detected as pure
earlier and that holds the same info.
