On Mon, 2 Nov 2020 10:47:18 GMT, Roland Westrelin <rol...@openjdk.org> wrote:
> This change add 3 new methods in Objects: > > public static long checkIndex(long index, long length) > public static long checkFromToIndex(long fromIndex, long toIndex, long length) > public static long checkFromIndexSize(long fromIndex, long size, long length) > > This mirrors the int utility methods that were added by JDK-8135248 > with the same motivations. > > As is the case with the int checkIndex(), the long checkIndex() method > is JIT compiled as an intrinsic. It allows the JIT to compile > checkIndex to an unsigned comparison and properly recognize it as > a range check that then becomes a candidate for the existing range check > optimizations. This has proven to be important for panama's > MemorySegment API and a prototype of this change (with some extra c2 > improvements) showed that panama micro benchmark results improve > significantly. > > This change includes: > > - the API change > - the C2 intrinsic > - tests for the API and the C2 intrinsic > > This is a joint work with Paul who reviewed and reworked the API change > and filled the CSR. This pull request has now been integrated. Changeset: a7422ac2 Author: Roland Westrelin <rol...@openjdk.org> URL: https://git.openjdk.java.net/jdk/commit/a7422ac2 Stats: 897 lines in 30 files changed: 846 ins; 4 del; 47 mod 8255150: Add utility methods to check long indexes and ranges Co-authored-by: Paul Sandoz <psan...@openjdk.org> Reviewed-by: jvernee, dlong, vlivanov ------------- PR: https://git.openjdk.java.net/jdk/pull/1003
