`AbstractStringBuilder.charAt(int)` does bounds check before calling `charAt()`
(for non-latin Strings):
@Override
public char charAt(int index) {
checkIndex(index, count);
if (isLatin1()) {
return (char)(value[index] & 0xff);
}
return StringUTF16.charAt(value, index);
}
This can be improved by removing bounds check from ASB.charAt() in favour of
one in String*.charAt(). This gives slight improvement:
before
Benchmark Mode Cnt Score Error Units
StringBuilderCharAtBenchmark.latin avgt 50 2,768 ± 0,004 ns/op
StringBuilderCharAtBenchmark.utf avgt 50 2,778 ± 0,014 ns/op
after
Benchmark Mode Cnt Score Error Units
StringBuilderCharAtBenchmark.latin avgt 50 2,434 ± 0,004 ns/op
StringBuilderCharAtBenchmark.utf avgt 50 2,631 ± 0,004 ns/op
-------------
Commit messages:
- 8270160 Remove redundant bounds check from AbstractStringBuilder.charAt()
Changes: https://git.openjdk.java.net/jdk/pull/4738/files
Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4738&range=00
Issue: https://bugs.openjdk.java.net/browse/JDK-8270160
Stats: 10 lines in 2 files changed: 1 ins; 5 del; 4 mod
Patch: https://git.openjdk.java.net/jdk/pull/4738.diff
Fetch: git fetch https://git.openjdk.java.net/jdk pull/4738/head:pull/4738
PR: https://git.openjdk.java.net/jdk/pull/4738
