JDK-7173584 : Implement arraycopy as a macro node
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: hs24
  • Priority: P3
  • Status: Resolved
  • Resolution: Fixed
  • OS: generic
  • CPU: generic
  • Submitted: 2012-06-01
  • Updated: 2014-11-14
  • Resolved: 2014-08-11
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JDK 9
9 b29Fixed
Related Reports
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JDK-6912521 - System.arraycopy works slower than the simple loop for little lengths
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JDK-8058746 - escape analysis special case code for array copy broken by 7173584
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JDK-6700100 - optimize inline_native_clone() for small objects with exact klass.
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JDK-8055153 - nsk/stress/jck60/jck60014 crashes on sparc
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JDK-8058349 - SPECjbb2005 1.4% performance regression on Linux with 9-b29
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JDK-8060252 - JDK-7173584 compiler changes regress SPECjvm2008 on SPARC
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JDK-6969165 - remove char[] allocation in new String(char[] buf) if buf does not escape
Description
When arraycopy is intrinsified, it is converted as calls to specialized stubs based on what's known from the context of the arraycopy. Right now, this is done at parsing. By using a new macro node for arraycopy that is expanded later, the compiler may be able to gather more data on the context of the arraycopy and make a better choice for the stub to call.

This also opens the door to other optimizations such as inlining small copies in a series of loads/stores.

This also impacts clone and Arrays.copyOf's implementations because they rely on the arraycopy stubs as well.
Comments
Any chance this can make it for 8?
14-06-2013
EVALUATION See description
01-06-2012