sibcall bug in ss-20000724 for i686-pc-linux

sibcall bug in ss-20000724 for i686-pc-linux

[Thomas R. Truscott]

In the program below, the optimizer turns do_sibcall's "call foo"
into "branch foo".  Unforunately for ia32, foo
returns a double that is pushed onto the floating point stack
and the caller must clean that up.
That would happen if do_sibcall also returned a double,
but alas it returns void.

On i686-pc-linux, "gcc -O2" does sibcall optimization
and the resulting program calls abort.

Tom Truscott

double
foo (void)
{
  return 0.0;
}

void
do_sibcall (void)
{
  (void) foo ();
}

int
main (void)
{
   double x;

   for (x = 0; x < 20; x++)
      do_sibcall ();
   if (!(x >= 10))
      abort ();
   exit (0);
}
>From aoliva@redhat.com Mon Jul 31 12:10:00 2000
From: Alexandre Oliva <aoliva@redhat.com>
To: Phil Edwards <pedwards@disaster.jaj.com>
Cc: gcc-bugs@gcc.gnu.org
Subject: Re: sed: command garbled
Date: Mon, 31 Jul 2000 12:10:00 -0000
Message-id: <orittmf75b.fsf@guarana.lsd.ic.unicamp.br>
References: <200007311746.NAA32639@disaster.jaj.com>
X-SW-Source: 2000-07/msg00783.html
Content-length: 500

On Jul 31, 2000, Phil Edwards <pedwards@disaster.jaj.com> wrote:

> breaks a build when libstdc++-v3 is enabled:

Yup, I've already posted another patch that addresses this problem.
Thanks for your bug report.

-- 
Alexandre Oliva   Enjoy Guarana', see http://www.ic.unicamp.br/~oliva/
Red Hat GCC Developer                  aoliva@{cygnus.com, redhat.com}
CS PhD student at IC-Unicamp        oliva@{lsd.ic.unicamp.br, gnu.org}
Free Software Evangelist    *Please* write to mailing lists, not to me