https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124049
Bug ID: 124049
Summary: Inconsistent assignment of union overhead values
Product: gcc
Version: 16.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: algol68
Assignee: algol68 at gcc dot gnu.org
Reporter: bohlj47 at gmail dot com
Target Milestone: ---
The following code produces incorrect output:
module-a.a68:
module Module_a =
def
pub mode Union_a = union (int,real);
pub proc union_a_string = (Union_a x) string:
case x
in (int): "int'n",
(real): "real'n"
esac;
skip
fed
module-b.a68:
module Module_b =
def
pub mode Union_b = union (real,int);
pub proc union_b_string = (Union_b x) string:
case x
in (int): "int'n",
(real): "real'n"
esac;
skip
fed
program.a68:
access Module_a,Module_b begin
Union_a a = 1;
Union_b b = 1;
puts(union_a_string(a));
puts(union_a_string(b));
puts(union_b_string(a));
puts(union_b_string(b))
end
To compile:
ga68 -c module-a.a68
ga68 -c module-b.a68
ga68 program.a68 module-a.o module-b.o
To run:
./a.out
The program outputs:
int
int
real
real
instead of the expected:
int
int
int
int
I have tracked the problem down to the union overhead values being assigned
differently when the packets are compiled. In modules-a.a68 and module-b.a68,
the overhead values are assigned in the order that the modes in the union are
specified. In program.a68 the overhead values are assigned the same as in
module-a.a68. When the union_b_string procedure is called it acts upon the
integer value as a real since it was compiled with the opposite overhead
assignment.
