On Fri, Apr 4, 2025 at 3:06 PM Robert Dubner <[email protected]> wrote:
>
> This program exhibits the behavior when compiled with -O2, -O3 and -OS
>
> PROGRAM-ID. PROG.
> PROCEDURE DIVISION.
> MOVE 1 TO RETURN-CODE
> STOP RUN.
Hmm, the call to exit() is still in the program.
0x000000000040114a <-358>: movswl 0x250f(%rip),%edi #
0x403660 <__gg__data_return_code>
0x0000000000401151 <-351>: mov %dx,(%rax)
=> 0x0000000000401154 <-348>: call 0x4010b0 <exit@plt>
$edi is 0 here. It looks like the store to __gg__data_return_code via
the move to (%rax)
and the load from it got interchanged due to aliasing issues possibly.
It works when compiling with -O2 -fno-strict-aliasing, so apparently
your override
which you said was present does not work. I can't find it, after all.
You want to implement the LANG_HOOKS_POST_OPTIONS hook and
do
flag_strict_aliasing = 0;
therein.
Richard.
>
> > -----Original Message-----
> > From: Richard Biener <[email protected]>
> > Sent: Friday, April 4, 2025 03:02
> > To: Robert Dubner <[email protected]>
> > Cc: GCC Mailing List <[email protected]>
> > Subject: Re: COBOL: Call to builtin_decl_explicit (BUILT_IN_EXIT), is
> > optimized away.
> >
> > On Fri, Apr 4, 2025 at 12:17 AM Robert Dubner <[email protected]> wrote:
> > >
> > > The COBOL compiler has this routine:
> > >
> > > void
> > > gg_exit(tree exit_code)
> > > {
> > > tree the_call =
> > > build_call_expr_loc(location_from_lineno(),
> > > builtin_decl_explicit (BUILT_IN_EXIT),
> > > 1,
> > > exit_code);
> > > gg_append_statement(the_call);
> > > }
> > >
> > > I have found that when GCOBOL is used with -O2, -O3, or -Os, the call to
> > > gg_exit() is optimized away, and the intended exit value is lost, and I
> > > end up with zero.
> > >
> > > By changing the routine to
> > >
> > > void
> > > gg_exit(tree exit_code)
> > > {
> > > tree args[1] = {exit_code};
> > > tree function = gg_get_function_address(INT, "exit");
> > > tree the_call = build_call_array_loc (location_from_lineno(),
> > > VOID,
> > > function,
> > > 1,
> > > args);
> > > gg_append_statement(the_call);
> > > }
> > >
> > > the call is not optimized away, and the generated executable behaves as
> > > expected.
> > >
> > > How do I prevent the call to gg_exit() from being optimized away?
> >
> > I don't see anything wrong here, so the issue must be elsewhere.
> > Do you have a COBOL testcase that shows the exit() being optimized?
> >
> > >
> > > Thanks!
> > >
