Most performant way of converting int to string

[rumbu via Digitalmars-d-learn]

On Tuesday, 22 December 2015 at 19:45:46 UTC, Daniel Kozák wrote:
> V Tue, 22 Dec 2015 18:11:24 +0000
> rumbu via Digitalmars-d-learn 
> <digitalmars-d-learn at puremagic.com>
> napsáno:
>
>> On Tuesday, 22 December 2015 at 17:15:27 UTC, Andrew Chapman 
>> wrote:
>> > Sorry if this is a silly question but is the to! method from 
>> > the conv library the most efficient way of converting an 
>> > integer value to a string?
>> >
>> > e.g.
>> > string s = to!string(100);
>> >
>> > I'm seeing a pretty dramatic slow down in my code when I use 
>> > a conversion like this (when looped over 10 million 
>> > iterations for benchmarking).
>> >
>> > Cheers!
>> 
>> Converting numbers to string involves the most expensive known 
>> two operations : division and modulus by 10.
>
> No, IIRC few months or maybe years I have optimize this so it 
> does not use division and modulus

It's using division and modulus, as expected:

https://github.com/D-Programming-Language/phobos/blob/master/std/conv.d#L5529

If the compiler is smart enough, maybe it will replace this by 
well known multiplication trick.