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From: Richard Henderson <richard.henderson@linaro.org>
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Date: Tue, 17 Oct 2017 21:30:15 -0700
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Subject: Re: [Qemu-devel] [PATCH v6 10/50] tcg: Avoid loops against variable
 bounds
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To: "Emilio G. Cota" <cota@braap.org>
Cc: qemu-devel@nongnu.org, Richard Henderson <rth@twiddle.net>

On 10/17/2017 03:03 PM, Emilio G. Cota wrote:
> On Mon, Oct 16, 2017 at 10:25:29 -0700, Richard Henderson wrote:
>> From: Richard Henderson <rth@twiddle.net>
>>
>> Copy s->nb_globals or s->nb_temps to a local variable for the purposes
>> of iteration.  This should allow the compiler to use low-overhead
>> looping constructs on some hosts.
>>
>> Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
>> Signed-off-by: Richard Henderson <rth@twiddle.net>
> 
> Reviewed-by: Emilio G. Cota <cota@braap.org>
> 
> FWIW on a Skylake host I couldn't measure a difference. However, the
> generated code is indeed slightly different.

I wouldn't expect so.  Low-overhead loops are more of a ppc thing.


r~