[Bug tree-optimization/61964] [4.8 regression] krb5 database propagation enters infinite loop; reduced test case

[andersk at mit dot edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61964

--- Comment #4 from Anders Kaseorg <andersk at mit dot edu> ---
Another bisect between 4.7 and 4.8 shows that the bug appeared with r189321
(bug 52009).

My test case has triggers the bug in more versions than Kerberos does: as far
as I can tell, Kerberos was unaffected until r192604.