https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120788
anlauf at gcc dot gnu.org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |WAITING
Last reconfirmed| |2025-06-23
Ever confirmed|0 |1
--- Comment #1 from anlauf at gcc dot gnu.org ---
You are invoking undefined behavior.
If you want wrapping on overflow, you can use -fwrapv, which gives:
hgng = -2147483648
hgt + 1 = -2147483648
hgt + 1 /= hgng = F
hgt + 1 == hgng = T
You can see where your code fails by compiling with -fsanitize=undefined:
hgng = -2147483648
pr120788.f90:8:33: runtime error: signed integer overflow: 2147483647 + 1
cannot be represented in type 'integer(kind=4)'
hgt + 1 = -2147483648
hgt + 1 /= hgng = F
hgt + 1 == hgng = T
