------- Comment #1 from ludovic at ludovic-brenta dot org 2007-02-09 14:34
-------
Shorter test case that reproduces the problem.
with Ada.Text_IO;
procedure test1 is
type T1 is mod 9;
package T1_IO is new Ada.Text_IO.Modular_IO(T1);
X: T1 := 8;
J1: constant := 5;
begin
for J2 in 5..5 loop
pragma assert(X*(2**J1) = X*(2**J2));
if X*(2**J1) /= X*(2**J2) then
Ada.Text_IO.Put_Line("Failed");
T1_IO.Put(X*(2**J1));
T1_IO.Put(X*(2**J2));
Ada.Text_IO.New_Line;
end if;
end loop;
end test1;
prints:
Failed
4 0
To reproduce: gnatmake test1
To reproduce with correct behaviour (no output): gnatmake -gnato test1
Notice that when multiplying by 2**J1, the result is always correct because J2
is a named number and the calculation is done at compile time with the correct
semantics. In contrast, J2 is non-static and exhibits the wrong semantics
unless we add -gnato.
Problem reproduced with GCC 4.1.1 but it's been there ever since 3.15p or even
before.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30740
