JDK-6680594 : Load + Load isn't canonicalized leading to missed GVN opportunities
  • Type: Bug
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: hs13
  • Priority: P4
  • Status: Resolved
  • Resolution: Fixed
  • OS: solaris_9
  • CPU: sparc
  • Submitted: 2008-03-26
  • Updated: 2013-11-01
  • Resolved: 2008-05-21
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JDK 6 JDK 7 Other
6u14Fixed 7Fixed hs13Fixed
Description
The logic for commuting binary operations ignores the case where both operations are loads so it doesn't canonicalize them based on idx which can lead to missing GVN opportunities.
Comments
SUGGESTED FIX repo: /net/jano2.sfbay/export2/hotspot/hg/hotspot-comp.clean changeset: 77:8a4ef4e001d3 user: never date: Fri Mar 28 09:00:39 2008 -0700 description: 6680594: Load + Load isn't canonicalized leading to missed GVN opportunities Reviewed-by: kvn, jrose files: src/share/vm/opto/addnode.cpp
28-03-2008
EVALUATION The fix is simply to handle Load + x and x + Load explicitly and allow Load + Load to fall through.
26-03-2008