From mboxrd@z Thu Jan  1 00:00:00 1970
From: Samuel Thibault <samuel.thibault@ens-lyon.org>
Subject: Re: [PATCH] minios: Fix incorrect {,
	un}likely() definitions
Date: Mon, 30 Jun 2014 18:00:42 +0200
Message-ID: <20140630160042.GN5027@type>
References: <1404143835-2151-1-git-send-email-andrew.cooper3@citrix.com>
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To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>, Xen-devel <xen-devel@lists.xen.org>
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Andrew Cooper, le Mon 30 Jun 2014 16:57:15 +0100, a =E9crit :
> As identified in e5545fb6, likely() and unlikely() must convert their
> expressions to booleans before comparing to 1 or 0, to avoid truncation
> issues.
> =

> While editing this file, add inclusion guards.
> =

> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
> CC: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> CC: Samuel Thibault <samuel.thibault@ens-lyon.org>

Acked-by: Samuel Thibault <samuel.thibault@ens-lyon.org>

> ---
>  extras/mini-os/include/compiler.h |    9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> =

> diff --git a/extras/mini-os/include/compiler.h b/extras/mini-os/include/c=
ompiler.h
> index e35c9d5..4188277 100644
> --- a/extras/mini-os/include/compiler.h
> +++ b/extras/mini-os/include/compiler.h
> @@ -1,5 +1,10 @@
> +#ifndef __MINIOS_COMPILER_H_
> +#define __MINIOS_COMPILER_H_
> +
>  #if __GNUC__ =3D=3D 2 && __GNUC_MINOR__ < 96
>  #define __builtin_expect(x, expected_value) (x)
>  #endif
> -#define unlikely(x)  __builtin_expect((x),0)
> -#define likely(x)  __builtin_expect((x),1)
> +#define unlikely(x)  __builtin_expect(!!(x),0)
> +#define likely(x)    __builtin_expect(!!(x),1)
> +
> +#endif /* __MINIOS_COMPILER_H_ */
> -- =

> 1.7.10.4
> =


-- =

Samuel
> No manual is ever necessary.
May I politely interject here: BULLSHIT.  That's the biggest Apple lie of a=
ll!
(Discussion in comp.os.linux.misc on the intuitiveness of interfaces.)