inlining

[JAnderson]

JAnderson wrote:
> bobef wrote:
>> This has probably been asked many times before. If someone knows of 
>> such discussion please paste me a link. Why not an 'inline' attribute? 
>> We all know that the compiler can be stupid some times, and even if it 
>> is not people may want to inline something that is normally not 
>> appropriate for inlining. Auto inlining is fine, but people should 
>> have control over such kind of things I believe.
>>
>> Regards, bobef
> 
> May C++ compilers ignore the inline attribute because it has a better 
> handle on when to inline.  There have been some studies (does anyone 
> have the links to these) where they've shown that most of the time the 
> compiler can make a more intelligent guess then the average engineer.
> 
> But that's C++.  D does this automatic virtual's thing so its difficult 
> to say whether the compiler can always make a good choice.
> 
> -Joel

I was working with MSVC++ the other day and found a couple of places 
where it wasn't inlining the code and was running slow.  So I placed a 
few inlines around and *bam* that code started running faster.  Then I 
profiled the code as a whole to see how much of an improvement I'd 
gained.  However the game was actually running slower.  It turned out 
that inlining had simply shifted the bottneck into memory and the 
program file size had got bigger, so the program cache was stalling all 
the time.

I'm not against inlining, I just think that you have to be really 
careful when using it and understand its implications (ie use a 
profiler), otherwise you could be making things worse.

-Joel