JDK-8269119 : C2: Avoid redundant memory barriers in Unsafe.copyMemory0 intrinsic
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: 17
  • Priority: P4
  • Status: Resolved
  • Resolution: Fixed
  • Submitted: 2021-06-22
  • Updated: 2023-10-03
  • Resolved: 2021-09-07
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JDK 18
18 b14Fixed
Related Reports
Duplicate :  
JDK-8269128 - C2: Avoid redundant memory barriers in Unsafe.copyMemory0 intrinsic
Relates :  
JDK-8316756 - C2 EA fails with "missing memory path" when encountering unsafe_arraycopy stub call
Relates :  
JDK-8268822 - Performance of bulk copy with segments seems suboptimal
Relates :  
JDK-8283122 - [AIX, s390] UnsafeCopyMemory 'Mismatched' Tests Fail on Big Endian Systems
Description
Unsafe::copyMemory0 intrinsic unconditionally inserts barriers arounds the call. It is conservative and barriers can be avoided in some cases (similar to what is done for scalar unsafe accesses; e.g., copying between on-heap arrays and off-heap is one of such cases).
Comments
Changeset: 377b1867 Author: Vladimir Ivanov <vlivanov@openjdk.org> Date: 2021-09-07 11:35:31 +0000 URL: https://git.openjdk.java.net/jdk/commit/377b186724473475480b834d99c38b8161bf6917
07-09-2021