On Tue, 11 Jun 2024 11:35:28 GMT, Shaojin Wen <d...@openjdk.org> wrote:
>> After PR https://github.com/openjdk/jdk/pull/16245, C2 optimizes stores into >> primitive arrays by combining values into larger stores. >> >> This PR rewrites the code of appendNull and append(boolean) methods so that >> these two methods can be optimized by C2. > > Shaojin Wen has updated the pull request incrementally with one additional > commit since the last revision: > > revert `-XX:DisableIntrinsic=_putCharStringU` causes performance degradation. As written in the comments of StringUTF16.putChar, no bounds checks, this is similar to Unsafe.putChar -XX:DisableIntrinsic=_putCharStringU Benchmark Mode Cnt Score Error Units StringBuilders.toStringCharWithNull8Utf16 avgt 15 9.063 ± 0.130 ns/op Benchmark Mode Cnt Score Error Units StringBuilders.toStringCharWithNull8Utf16 avgt 15 8.139 ± 0.018 ns/op class StringUTF16 { @IntrinsicCandidate // intrinsic performs no bounds checks static void putChar(byte[] val, int index, int c) { assert index >= 0 && index < length(val) : "Trusted caller missed bounds check"; index <<= 1; val[index++] = (byte)(c >> HI_BYTE_SHIFT); val[index] = (byte)(c >> LO_BYTE_SHIFT); } } ------------- PR Comment: https://git.openjdk.org/jdk/pull/19626#issuecomment-2162984481
