https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70992
--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
The bad recursion happens between extract_muldiv_1
/* The last case is if we are a multiply. In that case, we can
apply the distributive law to commute the multiply and addition
if the multiplication of the constants doesn't overflow
and overflow is defined. With undefined overflow
op0 * c might overflow, while (op0 + orig_op1) * c doesn't. */
if (code == MULT_EXPR && TYPE_OVERFLOW_WRAPS (ctype))
return fold_build2 (tcode, ctype,
fold_build2 (code, ctype,
fold_convert (ctype, op0),
fold_convert (ctype, c)),
op1);
which does (0 % 0 + 1) * 2 -> (0 % 0) * 2 + 2 and the reverse transformation
fold_plusminus_mult_expr does.
