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Date: Tue, 01 Jul 2014 08:52:07 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH fix for 2.1] makefile: Fix tools compile
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To: Alexey Kardashevskiy <aik@ozlabs.ru>, qemu-devel@nongnu.org
Cc: Peter Maydell <peter.maydell@linaro.org>, Alex Graf <agraf@suse.de>

Il 01/07/2014 07:42, Alexey Kardashevskiy ha scritto:
> This is wrong actually. The problem here that compiler knows how to
> optimize constants. sin(0.0) is the one while log(0.0) is not (it is
> supposed to throw error or something as it the result is infinity).
>
> So the correct test here could be:
> int main(void) { volatile double x = 1; return isnan(sin(x)); }
>
> But I am afraid pretty soon compilers will learn how to optimize this as
> well :)

I think something like "double x; int f(void) {return isnan(sin(x));}" 
should be bullet proof.

Paolo