Message-ID: <52653F3E.7030207@hp.com>
Date: Mon, 21 Oct 2013 10:50:38 -0400
From: Waiman Long <waiman.long@hp.com>
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To: Andi Kleen <andi@firstfloor.org>
CC: Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Paul Mackerras <paulus@samba.org>, Namhyung Kim <namhyung@kernel.org>,
        Jiri Olsa <jolsa@redhat.com>, Adrian Hunter <adrian.hunter@intel.com>,
        David Ahern <dsahern@gmail.com>, Stephane Eranian <eranian@google.com>,
        linux-kernel@vger.kernel.org, Aswin Chandramouleeswaran <aswin@hp.com>,
        Scott J Norton <scott.norton@hp.com>
Subject: Re: [PATCH v2 2/4] perf: streamline append_chain() function
References: <1382107129-2010-1-git-send-email-Waiman.Long@hp.com> <1382107129-2010-3-git-send-email-Waiman.Long@hp.com> <87ppr0u6n5.fsf@tassilo.jf.intel.com>
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On 10/19/2013 08:29 PM, Andi Kleen wrote:
> Waiman Long<Waiman.Long@hp.com>  writes:
>
>> as well as
>> using ?: statement which can be more efficient than the regular if
>> statement in some architectures.
> I don't think that's true, the compiler does if conversion anyways for both.
>
> But change seems reasonable.
>
> -Andi
>
>

That may be true for a simple if statement. However, the condition was 
checked as the last of 3 tests. I doubt if the compiler is able to 
optimize that effectively.

-Longman
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