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  1. JDK
  2. JDK-8239142

C2's UseUniqueSubclasses optimization is broken for array accesses

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    • Subcomponent:
    • Introduced In Build:
      b15
    • Introduced In Version:
      11
    • Resolved In Build:
      b11

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        Description

        If UseUniqueSubclasses is enabled, C2 tries to narrow the type of array elements on access to avoid type checks:
        http://hg.openjdk.java.net/jdk/jdk/file/690fc7e5a90f/src/hotspot/share/opto/parse2.cpp#l126

        But the fix for JDK-8202377 added code that overwrites the elemtype:
        http://hg.openjdk.java.net/jdk/jdk/rev/ffa644980dff#l27.26

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                Assignee:
                thartmann Tobias Hartmann
                Reporter:
                thartmann Tobias Hartmann
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