Re: [uml-devel] Re: [uml-user] SuSE 9.1 host + 2.4.26 Kernel + GCC 3.3.3 similarities to 2.6.6!?

[BlaisorBlade <blaisorblade_spam@yahoo.it>]

Alle 23:58, domenica 13 giugno 2004, Nix ha scritto:
> On Sun, 06 Jun 2004, uml@dot1q.net stipulated:
> > Switch differences between -O1 and -O2 on GCC 3.3.3:
>
> Note: -O{n} are *not* the equivalent of groups of -f switches:
> they turn those switches on, but other things inside the compiler
> are directly triggered by the optimization level.

I expected that SuSE 9.1 shipped a buggy gcc, but I didn't found any confirm 
to this (I remember they did such things in the past). However the fact that 
the compiler output that dump is anyway a compiler bug...

Well, ok, more hints, the first possible answer to this one seems to be that 
SuSE enables -funit-at-a-time:

http://www.google.com/search?q=%22SuSE+9.1%22+bug+gcc&sourceid=opera&num=25&ie=utf-8&oe=utf-8

I checked the first hit (read the whole thread):

http://gcc.gnu.org/ml/gcc-bugs/2004-05/msg01912.html

And this is interesting enough:

(they indeed speak about SuSE 9.1)

"This is a dup of bug 14911, well it looks like *SUSE turns on 
-funit-at-a-time at -O2 for their 3.3.3*, so 
using the same method as mentioned in the other bug except change the 
"__GNUC_MINOR__ >=4" to 
be "__GNUC_MINOR__ >= 3" and it will work."

Here is bug 14911:

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14911

This is the trick:
"#define ATTRIBUTE_USED
#if (__GNUC__ > 3) || (__GNUC__ == 3 && __GNUC_MINOR__ >=4)
#undef ATTRIBUTE_USED
#define ATTRIBUTE_USED __attribute__((used))
#endif
static const int hello ATTRIBUTE_USED  = 56;
int main()
{
        asm(
        "mov hello, %eax\n"
        );
        return 0;
}"
-- 
Paolo Giarrusso, aka Blaisorblade
Linux registered user n. 292729



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