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| author | Martin Möhrmann <moehrmann@google.com> | 2018-04-24 15:13:08 +0200 |
|---|---|---|
| committer | Martin Möhrmann <moehrmann@google.com> | 2018-05-06 05:31:01 +0000 |
| commit | b9a59d9f2e78ce497b38a984f62094a53e7dfce7 (patch) | |
| tree | c595460f4950f5f76d59cec82c651993ea449196 /src/unicode | |
| parent | a8a60ac2a7bec701de6b502889e1dc740761e183 (diff) | |
| download | go-b9a59d9f2e78ce497b38a984f62094a53e7dfce7.tar.gz go-b9a59d9f2e78ce497b38a984f62094a53e7dfce7.zip | |
cmd/compile: optimize len([]rune(string))
Adds a new runtime function to count runes in a string.
Modifies the compiler to detect the pattern len([]rune(string))
and replaces it with the new rune counting runtime function.
RuneCount/lenruneslice/ASCII 27.8ns ± 2% 14.5ns ± 3% -47.70% (p=0.000 n=10+10)
RuneCount/lenruneslice/Japanese 126ns ± 2% 60ns ± 2% -52.03% (p=0.000 n=10+10)
RuneCount/lenruneslice/MixedLength 104ns ± 2% 50ns ± 1% -51.71% (p=0.000 n=10+9)
Fixes #24923
Change-Id: Ie9c7e7391a4e2cca675c5cdcc1e5ce7d523948b9
Reviewed-on: https://go-review.googlesource.com/108985
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Diffstat (limited to 'src/unicode')
| -rw-r--r-- | src/unicode/utf8/utf8_test.go | 21 |
1 files changed, 16 insertions, 5 deletions
diff --git a/src/unicode/utf8/utf8_test.go b/src/unicode/utf8/utf8_test.go index dc9c4251bd..359461bd05 100644 --- a/src/unicode/utf8/utf8_test.go +++ b/src/unicode/utf8/utf8_test.go @@ -212,14 +212,25 @@ func TestSequencing(t *testing.T) { } } -// Check that a range loop and a []int conversion visit the same runes. +func runtimeRuneCount(s string) int { + return len([]rune(s)) // Replaced by gc with call to runtime.countrunes(s). +} + +// Check that a range loop, len([]rune(string)) optimization and +// []rune conversions visit the same runes. // Not really a test of this package, but the assumption is used here and -// it's good to verify -func TestIntConversion(t *testing.T) { +// it's good to verify. +func TestRuntimeConversion(t *testing.T) { for _, ts := range testStrings { + count := RuneCountInString(ts) + if n := runtimeRuneCount(ts); n != count { + t.Errorf("%q: len([]rune()) counted %d runes; got %d from RuneCountInString", ts, n, count) + break + } + runes := []rune(ts) - if RuneCountInString(ts) != len(runes) { - t.Errorf("%q: expected %d runes; got %d", ts, len(runes), RuneCountInString(ts)) + if n := len(runes); n != count { + t.Errorf("%q: []rune() has length %d; got %d from RuneCountInString", ts, n, count) break } i := 0 |