On Tue, 18 Jan 2022 16:27:11 GMT, Claes Redestad <redes...@openjdk.org> wrote:
>> This resolves minor inefficiency in the fast-path for decoding latin-1 chars >> from UTF-8. I also took the opportunity to refactor the StringDecode >> microbenchmark to align with recent changes to the StringEncode micro. >> >> The inefficiency is that this test is quite branchy: >> >> `if ((b1 == (byte)0xc2 || b1 == (byte)0xc3) && ...` >> >> Since the two constant bytes differ only on the lowest bit this can be >> transformed to this, saving us a branch: >> >> `if ((b1 & 0xfe) == 0xc2 && ...` >> >> This provides a small speed-up on microbenchmarks where the input can be >> internally encoded as latin1: >> >> >> Benchmark (charsetName) Mode Cnt Score Error Units >> StringDecode.decodeLatin1LongStart UTF-8 avgt 50 2283.591 ± 12.332 ns/op >> >> StringDecode.decodeLatin1LongStart UTF-8 avgt 50 2165.984 ± 13.136 ns/op > > Claes Redestad has updated the pull request incrementally with one additional > commit since the last revision: > > Rename and reorder latin1 micro Marked as reviewed by naoto (Reviewer). ------------- PR: https://git.openjdk.java.net/jdk/pull/7122
