Re: [RFC] intdiv()

On Thu, Jul 17, 2014 at 2:25 AM, Sara Golemon <pollita@php.net> wrote: > On Wed, Jul 16, 2014 at 8:15 AM, Andrea Faulds <ajf@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. > > 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. > This is already what is currently happening, see http://lxr.php.net/xref/PHP_TRUNK/Zend/zend_operators.c#1067. Andreas proposal is only useful in the case that the numbers don't divide exactly and you need round-down/truncation behavior and your numbers are in a range where the indirection through double arithmetic results in precision loss. Nikita