[Bug tree-optimization/77899] incorrect VR_RANGE for a signed char function argument

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77899

--- Comment #7 from Martin Sebor <msebor at gcc dot gnu.org> ---
Here's what I see in GDB after get_range_info returns to update_value_range:

(gdb) p rtype
$39 = VR_ANTI_RANGE
(gdb) p min
$40 = {<wide_int_storage> = {val = {128, 18061790, 140737235530016}, len = 1,
precision = 64}, static is_sign_extended = <optimized out>}
(gdb) p max
$41 = {<wide_int_storage> = {val = {-129, 18061836, 140737235530016}, len = 1,
precision = 64}, static is_sign_extended = <optimized out>}