https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92131
--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
From what I can see, the weird + 0x7ffffffffffffffe is created when
extract_range_from_plus_minus_expr is called with PLUS_EXPR and VARYING and
long int [-INF, e.7_8 + -1] ranges.
/* Build the symbolic bounds if needed. */
adjust_symbolic_bound (min, code, expr_type,
sym_min_op0, sym_min_op1,
neg_min_op0, neg_min_op1);
adjust_symbolic_bound (max, code, expr_type,
sym_max_op0, sym_max_op1,
neg_max_op0, neg_max_op1);
in there. max_op0 is 9223372036854775807 (maximum of VARYING), and max_op1 is
-1 (which is not the upper bound, just an offset against the symbolic).
combine_bound adds this into wmax, so 9223372036854775807 + -1 gives
0x7ffffffffffffffe and that is what is used. But e + 0x7ffffffffffffffe is
later considered that it is a huge value added to e in undefined overflow way
and thus e has to be at most 1. I think VARYING + [-INF, e.7_8 + -1] really
should be VARYING.
