[Bug rtl-optimization/72488] [7 Regression] wrong code (SIGFPE) at -Os and above on x86_64-linux-gnu (in the 64-bit mode)

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=72488

--- Comment #7 from Jeffrey A. Law <law at redhat dot com> ---
I poked at this a bit yesterday (given the irreducible loops I've got some
concerns that jump threading might be involved).  Whatever is going on, it is
highly sensitive to just about any codegen changes.  I've identified 3 separate
patches from August that can make the bug go latent.  Arggh.