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  1. JDK
  2. JDK-6384206

Phis which are later unneeded are impairing our ability to inline based on static types

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    Details

    • Type: Bug
    • Status: Resolved
    • Priority: P3
    • Resolution: Fixed
    • Affects Version/s: 6
    • Fix Version/s: hs14
    • Component/s: hotspot
    • Labels:
    • Subcomponent:
    • Resolved In Build:
      b06
    • CPU:
      x86, sparc
    • OS:
      linux, solaris_9

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        Description

        While investigating the performance of HashMap.get(k) I noticed that in cases where the static type of k is available C2 isn't taking advantage of the information in making it's inline decisions for get. The problem is that Phis which are introduced for the join of a diamond aren't being eliminated aggressively during parsing when one of the paths is proved dead. Additionally unneeded loop phis are hiding the type k in the search loop, impairing the inlining of equals. Post parse inlining which remove the need for aggressive elimination of phis but for now we need a better strategy for simplification of phis.

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                Assignee:
                never Tom Rodriguez
                Reporter:
                never Tom Rodriguez
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