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Re: KNF and the C preprocessor



On Dec 10, 2012, at 4:18 PM, David Young wrote:

> On Mon, Dec 10, 2012 at 03:50:00PM -0500, Thor Lancelot Simon wrote:
>> On Mon, Dec 10, 2012 at 02:28:28PM -0600, David Young wrote:
>>> On Mon, Dec 10, 2012 at 07:37:14PM +0000, David Laight wrote:
>>> 
>>>> a) #define macros tend to get optimised better.
>>> 
>>> Better even than an __attribute__((always_inline)) function?
>> 
>> I'd like to submit that neither are a good thing, because human
>> beings are demonstrably quite bad at deciding when things should
>> be inlined, particularly in terms of the cache effects of excessive
>> inline use.
> 
> I agree with that.  However, occasionally I have found when I'm
> optimizing the code based on actual evidence rather than hunches, and
> the compiler is letting me down, always_inline was necessary.
> 
> Dave

Is that because of compiler bugs, or because the compiler was doing what it's 
supposed to be doing?

        paul



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