Prior to this commit the `OPTIMIZED_CMP` macro relied on a method lookup
to determine whether `<=>` was overridden. The result of the lookup was
cached, but only for the duration of the specific method that
initialized the cmp_opt_data cache structure.
With this method lookup, `[x,y].max` is slower than doing `x > y ?
x : y` even though there's an optimized instruction for "new array max".
(John noticed somebody a proposed micro-optimization based on this fact
in https://github.com/mastodon/mastodon/pull/19903.)
```rb
a, b = 1, 2
Benchmark.ips do |bm|
bm.report('conditional') { a > b ? a : b }
bm.report('method') { [a, b].max }
bm.compare!
end
```
Before:
```
Comparison:
conditional: 22603733.2 i/s
method: 19820412.7 i/s - 1.14x (± 0.00) slower
```
This commit replaces the method lookup with a new CMP basic op, which
gives the examples above equivalent performance.
After:
```
Comparison:
method: 24022466.5 i/s
conditional: 23851094.2 i/s - same-ish: difference falls within
error
```
Relevant benchmarks show an improvement to Array#max and Array#min when
not using the optimized newarray_max instruction as well. They are
noticeably faster for small arrays with the relevant types, and the same
or maybe a touch faster on larger arrays.
```
$ make benchmark COMPARE_RUBY=<master@5958c305> ITEM=array_min
$ make benchmark COMPARE_RUBY=<master@5958c305> ITEM=array_max
```
The benchmarks added in this commit also look generally improved.
Co-authored-by: John Hawthorn <jhawthorn@github.com>
rb_ary_tmp_new suggests that the array is temporary in some way, but
that's not true, it just creates an array that's hidden and not on the
transient heap. This commit renames it to rb_ary_hidden_new.
Previously, this would work as expected if the enumerable contained
0 or 1 element, and would raise LocalJumpError otherwise. That
inconsistent behavior is likely to lead to bugs.
Fixes [Bug #18635]
This behavior changed in dfb47bbd17,
but only for normal exit, not for early exit. Fix it for early
exit as well.
While here, fix example code in documentation so that it doesn't
indicate that the method returns nil.
* Add test cases for Enumerable#tally with hash argument
* Add ruby/spec for Enumerable#tally with hash argument
* Fix Enumerable#tally does not update given frozen hash
* Add test cases for Enumerable#tally with hash convertible arguments
* Fix SEGV when Enumerable#tally takes non Hash convertible
* FIx cosmetic damage enum.c
Daniel Colson
S-H-GAMELINKS
Kouhei Yanagita
Peter Zhu
Takashi Kokubun
Burdette Lamar
Colin Hart
Jeremy Evans
Nobuyoshi Nakada
TSUYUSATO Kitsune
Kenichi Kamiya
Marc-Andre Lafortune
Kazuhiro NISHIYAMA
zverok
Stefan Stüben
卜部昌平