[Bug rtl-optimization/61657] Undefined behavior in loop-iv.c

[zeccav at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61657

--- Comment #5 from Vittorio Zecca <zeccav at gmail dot com> ---
Just confirmed adding
printf("up=%li down=%li up-down=%li\n", up,down,up-down);
before line 2670.
Output is
up=123 down=-9223372036854775808 up-down=-9223372036854775685

You could probably get an ICE with
gcc_assert(up-down>0);