Managing memory usage at Compile Time with DMD

[John Colvin via Digitalmars-d-learn]

On Thursday, 9 April 2015 at 11:05:22 UTC, John Colvin wrote:
> On Thursday, 9 April 2015 at 10:23:06 UTC, wobbles wrote:
>> On Thursday, 9 April 2015 at 10:04:09 UTC, John Colvin wrote:
>>> On Thursday, 9 April 2015 at 09:49:39 UTC, wobbles wrote:
>>>> Another possibilty I was looking at was to write a tool that 
>>>> will spit out all combinations at runtime, and then import 
>>>> these back into the bot at compile time to build a lookup 
>>>> table that way.
>>>>
>>>> Thanks!
>>>
>>> This is definitely a better idea. I would probably load them 
>>> at runtime instead, it scales better.
>>
>> But if the compiler knows about all the values at compile 
>> time, it will be able to optimise things better than at 
>> runtime?
>
> Well, it depends. Sometimes it makes a big difference, other 
> times there's not much, if any, advantage. The only way to 
> reason about it is to look at your code and think about what 
> the compiler might be able to do given certain information, 
> then check the asm to see if it's actually doing it.

or just time it, of course. But even that has pitfalls and
difficulties. Optimisation is difficult.