Re: Bug in haifa scheduler ?

[Gabriel Paubert <paubert at iram dot es>]

On Thu, 25 Jun 1998, Franz Sirl wrote:

> ;-). You would have noticed a failing test compile/980511-1.c, which is a
> stripped down super.c.

I tried once to run the testsuite. There is too much output. 

> This will (hopefully!) be fixed for 1.1. For now simply add the following
> lines at the top of fs/Makefile:
> 
> CFLAGS_super.o += -fno-expensive-optimizations
> CFLAGS_namei.o += -fno-expensive-optimizations
> 
> The namei change makes mknod working. Additionally I would recommend the

Strange, it seems I never need mknod ! Been using the machine for a while
without noticing any problem. 

> following patch for io.h:
> 
> Index: io.h
> ===================================================================
> RCS file: /cvsroot/linux/include/asm-ppc/io.h,v
> retrieving revision 1.29
> diff -u -r1.29 io.h
> --- io.h        1998/06/23 20:06:13     1.29
> +++ io.h        1998/06/23 23:15:44
> @@ -202,7 +202,7 @@
>   */
>  extern inline void eieio(void)
>  {
> -       asm volatile ("eieio" : :);
> +       __asm__ __volatile__ ("eieio" : : : "memory" );
>  }
>  
>  /*
> 
> 
> Hope this helps,


What worries me is that a memory clobber effectively disables many 
optimizations. All I/O macros use pointers to volatile or volatile
asm statements, and I thouht that these would already prevent the compiler
from  reordering but allow it to keep values in register across the
I/O access. 

	Regards,
	Gabriel.