Add testcase for possible bug in gcc-4_4 ix86 branch

The jump was only there because I narrowed down the problem code from
a C file and the jump was in the original code.

I was able to reproduce the problem with a simpler testcase, which is
below. This fails with this patch
(http://gcc.gnu.org/viewcvs?view=revision&revision=153780), but passes
otherwise. It passes on gcc trunk as well (I tested after configuring
--with-target= i386 and x86_64).

Comments? OK for a resubmission?

~/a/gcc-svn-rw/trunk


On Mon, Dec 13, 2010 at 5:00 PM, Ian Lance Taylor <iant@google.com> wrote:
> asharif tools <asharif.tools@gmail.com> writes:
>
>> Index: gcc/testsuite/gcc.target/i386/max-stack-align.c
>> ===================================================================
>> --- gcc/testsuite/gcc.target/i386/max-stack-align.c   (revision 0)
>> +++ gcc/testsuite/gcc.target/i386/max-stack-align.c   (revision 0)
>> @@ -0,0 +1,13 @@
>> +/* { dg-do compile } */
>> +/* { dg-options "-fomit-frame-pointer" } */
>> +/* { dg-require-effective-target lp64 } */
>> +
>> +void foo()
>> +{
>> +  int a=0, b=0, c=0, e=0, f=0, g=0, h=0, i=0;
>> +label:
>> +     __asm__ volatile( " jb label "
>> +                       : : "c" (a), "d" (a), "S" (a), "D" (a), "r" (a), "a" (a) ,"r" (a), "r" (a)
>> +                       : "%""rbp" );
>> +}
>
> I don't understand why you want to have a jump in the asm.  But, if you
> do need one, you need to also define the label in the asm, not in the C
> code.  The C label "label" is not going to be named "label" in the
> assembler code.
>
> Ian
>

asharif tools <asharif.tools@gmail.com> writes:

> Index: gcc/testsuite/gcc.target/i386/max-stack-align.c
> ===================================================================
> --- gcc/testsuite/gcc.target/i386/max-stack-align.c	(revision 0)
> +++ gcc/testsuite/gcc.target/i386/max-stack-align.c	(revision 0)
> @@ -0,0 +1,14 @@
> +/* { dg-do compile } */
> +/* { dg-options "-fomit-frame-pointer" } */
> +/* { dg-require-effective-target lp64 } */
> +
> +void foo()
> +{
> +  int a=0, b=0, c=0, e=0, f=0, g=0, h=0, i=0;
> +	__asm__ __volatile__ ("addl 	%%rbp,%%rbp"
> +		: "=rbp"(a)
> +		: "rbp"(b)
> +		: "rbp"
> +	);
> +}

You should be able to use "=r" and "r" instead of "=rbp" and "rbp".  If
that works, then this patch is OK.

Thanks.

Ian

On Mon, Dec 13, 2010 at 08:20:38PM -0800, Ian Lance Taylor wrote:
> asharif tools <asharif.tools@gmail.com> writes:
> 
> > Index: gcc/testsuite/gcc.target/i386/max-stack-align.c
> > ===================================================================
> > --- gcc/testsuite/gcc.target/i386/max-stack-align.c	(revision 0)
> > +++ gcc/testsuite/gcc.target/i386/max-stack-align.c	(revision 0)
> > @@ -0,0 +1,14 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-fomit-frame-pointer" } */
> > +/* { dg-require-effective-target lp64 } */
> > +
> > +void foo()
> > +{
> > +  int a=0, b=0, c=0, e=0, f=0, g=0, h=0, i=0;
> > +	__asm__ __volatile__ ("addl 	%%rbp,%%rbp"
> > +		: "=rbp"(a)
> > +		: "rbp"(b)
> > +		: "rbp"
> > +	);
> > +}
> 
> You should be able to use "=r" and "r" instead of "=rbp" and "rbp".  If
> that works, then this patch is OK.

Also, please try to trim the list of variables (c through i), if you can
still reproduce the problem with the testcase.  And you can probably use
just "" instead of "addl %%rbp,%%rbp".

	Jakub