RFR: 8302850: Consider implementing a C1 clone intrinsic that uses ArrayCopyNode for primitive arrays

[Galder Zamarreño]

Adding C1 intrinsic for primitive array clone invocations for aarch64 and x86 architectures.

The intrinsic includes a change to avoid zeroing the newly allocated array because its contents are copied over within the same intrinsic with arraycopy. This means that the performance of primitive array clone exceeds that of primitive array copy. As an example, here are the microbenchmark results on darwin/aarch64:


$ make test TEST="micro:java.lang.ArrayClone" MICRO="JAVA_OPTIONS=-XX:TieredStopAtLevel=1"
Benchmark                 (size)  Mode  Cnt    Score    Error  Units
ArrayClone.byteArraycopy       0  avgt   15    3.476 ?  0.018  ns/op
ArrayClone.byteArraycopy      10  avgt   15    3.740 ?  0.017  ns/op
ArrayClone.byteArraycopy     100  avgt   15    7.124 ?  0.010  ns/op
ArrayClone.byteArraycopy    1000  avgt   15   39.301 ?  0.106  ns/op
ArrayClone.byteClone           0  avgt   15    3.478 ?  0.008  ns/op
ArrayClone.byteClone          10  avgt   15    3.562 ?  0.007  ns/op
ArrayClone.byteClone         100  avgt   15    5.888 ?  0.206  ns/op
ArrayClone.byteClone        1000  avgt   15   25.762 ?  0.203  ns/op
ArrayClone.intArraycopy        0  avgt   15    3.199 ?  0.016  ns/op
ArrayClone.intArraycopy       10  avgt   15    4.521 ?  0.008  ns/op
ArrayClone.intArraycopy      100  avgt   15   17.429 ?  0.039  ns/op
ArrayClone.intArraycopy     1000  avgt   15  178.432 ?  0.777  ns/op
ArrayClone.intClone            0  avgt   15    3.406 ?  0.016  ns/op
ArrayClone.intClone           10  avgt   15    4.272 ?  0.006  ns/op
ArrayClone.intClone          100  avgt   15   13.110 ?  0.122  ns/op
ArrayClone.intClone         1000  avgt   15  113.196 ? 13.400  ns/op


It also includes an optimization to avoid instantiating the array copy stub in scenarios like this.

I run hotspot compiler tests successfully limiting them to C1 compilation darwin/aarch64, linux/x86_64 and linux/686. E.g.


$ make test TEST="hotspot_compiler" JTREG="JAVA_OPTIONS=-XX:TieredStopAtLevel=1"
...
   TEST                                              TOTAL  PASS  FAIL ERROR
   jtreg:test/hotspot/jtreg:hotspot_compiler          1234  1234     0     0


One question I had is what to do about non-primitive object arrays, see my [question](https://bugs.openjdk.org/browse/JDK-8302850?focusedId=14634879&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-14634879) on the issue. @cl4es any thoughts?

Thanks @rwestrel for his help shaping this up :)

-------------

Commit messages:
 - 8302850: Avoid instantiating array copy stub for clone use cases
 - 8302850: Primitive array copy C1 intrinsic for aarch64 and x86

Changes: https://git.openjdk.org/jdk/pull/17667/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17667&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8302850
  Stats: 224 lines in 18 files changed: 203 ins; 0 del; 21 mod
  Patch: https://git.openjdk.org/jdk/pull/17667.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17667/head:pull/17667

PR: https://git.openjdk.org/jdk/pull/17667