From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Subject: Re: [PATCH v4 01/17] x86/mpx: Do not use SIB index if index points
 to R/ESP
Date: Fri, 24 Feb 2017 11:07:27 -0800
Message-ID: <1487963247.115017.10.camel@ranerica-desktop>
References: <20170223063706.71554-1-ricardo.neri-calderon@linux.intel.com>
         <20170223063706.71554-2-ricardo.neri-calderon@linux.intel.com>
         <20170223072432.GX6515@twins.programming.kicks-ass.net>
         <1487888232.115017.4.camel@ranerica-desktop>
         <1487903602.14159.50.camel@perches.com>
         <CADRb1HZSxmt69V7MEUGMNUHqmfFbOMGVZPp+qLfwAu17KNRh=g@mail.gmail.com>
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit
Return-path: <linux-msdos-owner@vger.kernel.org>
In-Reply-To: <CADRb1HZSxmt69V7MEUGMNUHqmfFbOMGVZPp+qLfwAu17KNRh=g@mail.gmail.com>
Sender: linux-msdos-owner@vger.kernel.org
List-ID: <linux-msdos.vger.kernel.org>
Content-Type: text/plain; charset="us-ascii"
To: Nathan Howard <liverlint@gmail.com>
Cc: Joe Perches <joe@perches.com>, Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, linux-msdos@vger.kernel.org, Lorenzo Stoakes <lstoakes@gmail.com>, "Ravi V. Shankar" <ravi.v.shankar@intel.com>, Andrew Morton <akpm@linux-foundation.org>, "Michael S. Tsirkin" <mst@redhat.com>, Adam Buchbinder <adam.buchbinder@gmail.com>, Alexandre Julliard <julliard@winehq.org>, Qiaowei Ren <qiaowei.ren@intel.com>, Vlastimil Babka <vbabka@suse.cz>, Chris Metcalf <cmetcalf@mellanox.com>, wine-devel@winehq.org, Jiri Slaby <jslaby@suse.cz>, x86@kernel.org, Liang Z Li <liang.z.li@intel.com>, Stas Sergeev <stsp@list.ru>, Paolo Bonzini <pbonzini@redhat.com>, Dave Hansen <dave.hansen@linux.intel.com>, Paul Gortmaker <paul.gortmaker@windriver.com>

On Fri, 2017-02-24 at 09:47 -0500, Nathan Howard wrote:
>         Also, this code would read better with the inner test
>         reversed or done first
>         
>                         if (indx_offset < 0) {
>                                 if (indx_offset != -EDOM)
>                                         goto out_err;
>                                 indx = 0;
>                         } else {
>                                 indx = regs_get_register(etc...)
>                         }
>         
>         or
>                         if (indx_offset == -EDOM)
>                                 indx = 0;
>                         else if (indx_offset < 0)
>                                 goto err;
> 
> 
> Or goto out_err;
> 
> 
>                         else
>                                 indx = regs_get_register(etc...)
>         
>         The compiler should generate the same code in any
>         case, but either could improve reader understanding.
> 
> 
> Also, it may be a tweak more efficient to handle the most likely
> runtime case in the conditional stack first (whichever that may be).

The most likely case will be a positive value but I need to check for
negatives first :( I could wrap the first conditional in an "unlikely".

Thanks and BR,
Ricardo