[Bug tree-optimization/78574] [7 Regression] ice on valid C code at -O2 and -O3 in both 32- and 64-bit modes on x86_64-linux-gnu (internal compiler error: Segmentation fault (program cc1))

[amker at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78574

--- Comment #4 from amker at gcc dot gnu.org ---
(In reply to Jakub Jelinek from comment #2)
> Seems there is infinite recursion in find_deriving_biv_for_expr.
> It endlessly alternates being called on lhs of
> j_11 = PHI <j_18(D)(2), _24(17)>
> and lhs of
> _24 = j_11 + 1;
> get_iv (data, expr) for these returns iv with biv_p = false, base of j_18(D)
> or j_18(D) + 1, step 1.  Dunno why there isn't a biv.

I think it's not even a valid IV because the increment is in an inner loop
which is irreducible.  we may need to identify the case and break out early.