Passing array as const slows down code?

[Steven Schveighoffer]

On Fri, 27 Apr 2012 11:33:39 -0400, Joseph Rushton Wakeling  
<joseph.wakeling at webdrake.net> wrote:

> On 27/04/12 17:18, Steven Schveighoffer wrote:
>> const should not affect code generation *at all*, except for name  
>> mangling
>> (const MyStruct is a different type from MyStruct), and generating an  
>> extra
>> TypeInfo for const MyStruct and const MyStruct[]. Const is purely a  
>> compile-time
>> concept.
>>
>> This cannot account for an extra 2 seconds. Something else is happening.
>>
>> Without more of your code, nobody can give a definitive answer except  
>> it is not
>> supposed to affect it.
>
> The code is here: https://github.com/WebDrake/Dregs/
>
> ... and the particular file concerned is
> https://github.com/WebDrake/Dregs/blob/master/dregs/codetermine.d
>
> You'll see that there are about 8 different functions in there which  
> receive as input an array of type Rating!(UserID, ObjectID,  
> Reputation)[].  These were the inputs I was marking as const.

Hm.. you have marked all your functions pure as well.  I don't think this  
will affect anything in the current implementation, but it might.   
However, I'd expect the opposite (const version is faster) if anything.

-Steve