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Date: Wed, 11 Dec 2013 12:07:21 -0800
From: Andi Kleen <ak@linux.intel.com>
To: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Ingo Molnar <mingo@redhat.com>, linux-kernel@vger.kernel.org,
        David Ahern <dsahern@gmail.com>,
        Frederic Weisbecker <fweisbec@gmail.com>, Jiri Olsa <jolsa@redhat.com>,
        Mike Galbraith <efault@gmx.de>, Namhyung Kim <namhyung@gmail.com>,
        Paul Mackerras <paulus@samba.org>,
        Stephane Eranian <eranian@google.com>,
        Adrian Hunter <adrian.hunter@intel.com>
Subject: Re: [PATCH v0 21/71] perf tools: Add feature test for
 __sync_val_compare_and_swap
Message-ID: <20131211200721.GN22695@tassilo.jf.intel.com>
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> Can you provide more info about these gcc builtins and what is the
> minimum system where this test will succeed?

CMPXCHG for x86 is available since the 486 or so, so practically
everywhere.

I think that's mainly for other architectures.

it would be reasonable to just use #if defined(__x86_64__) || defined(__i386__)
instead.

-Andi