Message-ID: <47e6d710-d666-5f5b-5d65-4f31afe4359d@gonehiking.org>
Date:   Tue, 7 Feb 2023 08:28:22 -0700
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Reply-To: khalid@gonehiking.org
Subject: Re: [PATCH] scsi: FlashPoint: Replace arithmetic addition by bitwise
 OR
To:     jejb@linux.ibm.com, Deepak R Varma <drv@mailo.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     Saurabh Singh Sengar <ssengar@microsoft.com>,
        Praveen Kumar <kumarpraveen@linux.microsoft.com>
References: <Y+I0HXsHezZRtFOM@ubun2204.myguest.virtualbox.org>
 <9a78cdd254d5d962450242d2e01c3a0f702a63a0.camel@linux.ibm.com>
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From:   Khalid Aziz <khalid@gonehiking.org>
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On 2/7/23 05:26, James Bottomley wrote:
> On Tue, 2023-02-07 at 16:51 +0530, Deepak R Varma wrote:
>> When adding two bit-field mask values, an OR operation offers higher
>> performance over an arithmetic operation. So, convert such additions
>> to an OR based expressions. Issue identified using orplus.cocci
>> semantic patch script.
> 
> No it doesn't, at least not for constants, which is the entirety of
> this patch: the compiler can find the value at compile time, so the
> whole lot becomes a load immediate of a single value.  Whether the
> compiler sees OR or + is immaterial to the compile time computation.
> Perhaps Coccinelle should be fixed not to complain about this case?
> 
> James
> 

Agreed. This would be lot of code changes for no benefit.

--
Khalid