[Bug target/69533] [6 Regression] python miscompilation

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69533

--- Comment #2 from Jeffrey A. Law <law at redhat dot com> ---
Quick update.  It appears that we've got something like this


t = b * c;
r = b / c;

if (r != b)
   ....


Which python is using as an overflow check.  We now know how to optimize the
mul/div sequence, which in turn causes the IF statement to have a known value. 
Ultimately we end up removing the overflow check, which appears to make the
python testsuite unhappy.