[Bug tree-optimization/69740] [5/6 Regression] gcc ICE at -O2 and above on valid code on x86_64-linux-gnu in "verify_loop_structure"

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69740

--- Comment #5 from Jeffrey A. Law <law at redhat dot com> ---
The testcase in c#3 is another instance of this problem, but triggered by
sinking.  I'd already been pondering the benefit/risk of attacking this at a
higher level (like in delete_basic_block) and seeing another instance from a
completely different codepath makes me think this check ought to be implemented
in a common path rather than in each place were we call delete_basic_block.