Issue #15589 has been updated by mame (Yusuke Endoh).


sawa (Tsuyoshi Sawada) wrote:
> So I think there are two ways to go. One: Acknowledge that there are uses for these methods, and optimize them, or Two: Make them obsolete, in which case the original use cases should use `== 0`.

Don't be extreme.  Both "One" and "Two" is unreasonable to me.  My "Three": Let it be.  Speed consistency is a too weak reason to do anything.


Eregon (Benoit Daloze) wrote:
> If zero? was written in Ruby (like it is in Rubinius & TruffleRuby), and Ruby inlining was implemented (TruffleRuby does), then there should be very little difference once #zero? is compiled by the JIT.

I think that this is the way to go.  So I assigned this to k0kubun.  (I think the priority is very low, though.)

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Bug #15589: `Numeric#zero?` is much slower than `== 0`
https://bugs.ruby-lang.org/issues/15589#change-76703

* Author: sawa (Tsuyoshi Sawada)
* Status: Open
* Priority: Normal
* Assignee: k0kubun (Takashi Kokubun)
* Target version: 
* ruby -v: 2.6.1
* Backport: 2.4: UNKNOWN, 2.5: UNKNOWN, 2.6: UNKNOWN
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My understanding is that the predicate method `Numeric#zero?` is not only a shorthand for `== 0`, but is also optimized for frequent patterns. If `zero?` is not faster than `== 0`, then it loses its reason for existence.

However, According to benchmarks on my environment, `number.zero?` is around 1.23 times to 1.64 times slower than `number == 0` when `number` is an `Integer`, `Rational`, or `Complex`. It is faster only when `number` is a `Float`.

And with `number.nonzero?`, it is even worse. It is about 1.88 times to 4.35 times slower than `number != 0`.

I think there is something wrong with this, and it should be possible to optimize these methods, which has somehow been missed.



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