Hi Sara,
On Thu, Jul 17, 2014 at 8:25 AM, Sara Golemon <poll...@php.net> wrote:
> On Wed, Jul 16, 2014 at 8:15 AM, Andrea Faulds <a...@ajf.me> wrote:
> > Nikita Popov doesn’t seem to be a fan of the %% syntax, so it may be
> subject to change, though I think it’s the best I’ve heard so far. ;)
> >
> Nor am I. Here's a thought though: How about just making / return int
> when there's no remainder.
>
> Looking at this code, you might think it's inefficent:
>
> double dres = a / b;
> long lres = a / b;
> if (a % b) {
> return dres;
> } else {
> return lres;
> }
>
> But in fact at -O1, gcc will optimize this (probably clang and others
> as well) to a single idivq instruction and only do the cvtsi2sdq in
> the dres case.
>
Just out of curiosity, does the compiler optimise it into something like
this?
if (a % b) {
return a / b;
} else {
return (double)a / b;
}
Or, would writing it like that skip the optimisation of being able to fetch
the division result from %rax?
> My point being, we can just make division with an integral result
> return a result of integer division without altering the syntax or
> adding a perf hit.
>
> -Sara
>
> --
> PHP Internals - PHP Runtime Development Mailing List
> To unsubscribe, visit: http://www.php.net/unsub.php
>
>
--
--
Tjerk
