[Bug tree-optimization/69989] [6 Regression] ICE on x86_64-linux-gnu at -O3 in both 32-bit and 64-bit modes (in verify_loop_structure, at cfgloop.c:1639)

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69989

--- Comment #3 from Jeffrey A. Law <law at redhat dot com> ---
WRT fallout and reverting on the gcc-5 branch.  Based on what I'm seeing, that
may make sense.

The problem in this particular case is we've marked loops for fixup, then loop
distribution is explicitly calling checking_verify_loop_structure.

checking_verify_loop_structure will assert that loops do not need fixup, and of
course, that assertion fails.  There's at least a half-dozen of these explicit
calls that can fail in a similar manner.

I'm going to poke a bit, but my inclination is to pull the patch from the trunk
and the branch.