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 ------------- Commit messages: - 8269559: AArch64: Implement string_compare intrinsic in SVE Changes: https://git.openjdk.java.net/jdk/pull/5129/files Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5129&range=00 Issue: https://bugs.openjdk.java.net/browse/JDK-8269559 Stats: 550 lines in 12 files changed: 447 ins; 12 del; 91 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
