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Date: Thu, 28 May 2009 00:41:00 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Amerigo Wang <amwang@redhat.com>
Cc: linux-kernel@vger.kernel.org, Sam Ravnborg <sam@ravnborg.org>
Subject: Re: [Patch] kbuild: fix a compile warning
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On Fri, 15 May 2009 03:51:18 -0400 Amerigo Wang <amwang@redhat.com> wrote:

> 
> I got this warning:

With which gcc version?

>  HOSTCC  scripts/basic/fixdep
> scripts/basic/fixdep.c: In function 'traps':
> scripts/basic/fixdep.c:377: warning: dereferencing type-punned pointer will break strict-aliasing rules
> scripts/basic/fixdep.c:379: warning: dereferencing type-punned pointer will break strict-aliasing rules
> 

(wtf?)

> 
> --- a/scripts/basic/fixdep.c
> +++ b/scripts/basic/fixdep.c
> @@ -373,10 +373,11 @@ void print_deps(void)
>  void traps(void)
>  {
>  	static char test[] __attribute__((aligned(sizeof(int)))) = "CONF";
> +	int *p = (int *)test;
>  
> -	if (*(int *)test != INT_CONF) {
> +	if (*p != INT_CONF) {
>  		fprintf(stderr, "fixdep: sizeof(int) != 4 or wrong endianess? %#x\n",
> -			*(int *)test);
> +			*p);
>  		exit(2);
>  	}
>  }