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Date: Fri, 30 Jun 2017 17:15:14 -0400
From: "Emilio G. Cota" <cota@braap.org>
Message-ID: <20170630211514.GA13753@flamenco>
References: <20170630153946.11997-1-bobby.prani@gmail.com>
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In-Reply-To: <20170630153946.11997-1-bobby.prani@gmail.com>
Subject: Re: [Qemu-devel] [PATCH] util/cacheinfo: Fix warning generated by
 clang
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To: Pranith Kumar <bobby.prani@gmail.com>
Cc: Richard Henderson <rth@twiddle.net>, "open list:All patches CC here" <qemu-devel@nongnu.org>

On Fri, Jun 30, 2017 at 11:39:46 -0400, Pranith Kumar wrote:
> Clang generates the following warning on aarch64 host:
> 
>   CC      util/cacheinfo.o
> /home/pranith/qemu/util/cacheinfo.c:121:48: warning: value size does not match register size specified by the constraint and modifier [-Wasm-operand-widths]
>         asm volatile("mrs\t%0, ctr_el0" : "=r"(ctr));
>                                                ^
> /home/pranith/qemu/util/cacheinfo.c:121:28: note: use constraint modifier "w"
>         asm volatile("mrs\t%0, ctr_el0" : "=r"(ctr));
>                            ^~
>                            %w0
> 
> Constraint modifier 'w' is not (yet?) accepted by gcc. Fix this by increasing the ctr size.
> 
> Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>

I can reproduce with clang 3.9.1.

Tested-by: Emilio G. Cota <cota@braap.org>
Reviewed-by: Emilio G. Cota <cota@braap.org>

Thanks,

		Emilio