> This patch implements string_compare intrinsic in SVE. > It supports all LL, LU, UL and UU comparisons. > > As we haven't found an existing benchmark to measure performance impact, > we created a benchmark derived from the test [1] for this evaluation. > This benchmark is attached to this patch. > > Besides, remove the unused temporary register `vtmp3` from the existing > match rules for StrCmp. > > The result below shows all varients can be benefited largely. > Command: make exploded-test TEST="micro:StringCompareToDifferentLength" > > Benchmark (size) Mode Cnt Score Speedup Units > compareToLL 24 avgt 10 1.0x ms/op > compareToLL 36 avgt 10 1.0x ms/op > compareToLL 72 avgt 10 1.0x ms/op > compareToLL 128 avgt 10 1.4x ms/op > compareToLL 256 avgt 10 1.8x ms/op > compareToLL 512 avgt 10 2.7x ms/op > compareToLU 24 avgt 10 1.6x ms/op > compareToLU 36 avgt 10 1.8x ms/op > compareToLU 72 avgt 10 2.3x ms/op > compareToLU 128 avgt 10 3.8x ms/op > compareToLU 256 avgt 10 4.7x ms/op > compareToLU 512 avgt 10 6.3x ms/op > compareToUL 24 avgt 10 1.6x ms/op > compareToUL 36 avgt 10 1.7x ms/op > compareToUL 72 avgt 10 2.2x ms/op > compareToUL 128 avgt 10 3.3x ms/op > compareToUL 256 avgt 10 4.4x ms/op > compareToUL 512 avgt 10 6.1x ms/op > compareToUU 24 avgt 10 1.0x ms/op > compareToUU 36 avgt 10 1.0x ms/op > compareToUU 72 avgt 10 1.4x ms/op > compareToUU 128 avgt 10 2.2x ms/op > compareToUU 256 avgt 10 2.6x ms/op > compareToUU 512 avgt 10 3.7x ms/op > > [1] > https://github.com/openjdk/jdk/blob/master/test/hotspot/jtreg/compiler/intrinsics/string/TestStringCompareToDifferentLength.java
TatWai Chong has updated the pull request incrementally with one additional commit since the last revision: Restore the removal of vtmp3 (=V2) as it is still used by the non-SVE compare-long-strings stub. And remove the assertion in `string_compare` since it won't help as the registers used in the stub are fixed. ------------- Changes: - all: https://git.openjdk.java.net/jdk/pull/5129/files - new: https://git.openjdk.java.net/jdk/pull/5129/files/bae862e1..2ae102d0 Webrevs: - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=5129&range=01 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=5129&range=00-01 Stats: 31 lines in 6 files changed: 6 ins; 2 del; 23 mod Patch: https://git.openjdk.java.net/jdk/pull/5129.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/5129/head:pull/5129 PR: https://git.openjdk.java.net/jdk/pull/5129
