Re: [PATCH] perf tools: Prevent from BITS_PER_LONG redefinition

[Jeremy Fitzhardinge]

On 12/31/2009 08:45 AM, Frederic Weisbecker wrote:
> > You can use if() with a constant expression instead of #if.
> >      
>
>
> I did not write this code. But yes you're right, although I
> think CPP is more suitable here because fls() can be called
> from fastpath and this conditional build makes one check less
> and lesser i-cache footprint.
>    

Constant if()s are removed at compile time, so there should be no 
runtime overhead.  Constant if()s are generally preferable to #if 
because the compile will statically check the other code branch, even if 
it never gets executed, which helps prevent it from rotting.

    J

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