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  1. JDK
  2. JDK-8278228

C2: Improve identical back-to-back if elimination

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Details

    • Enhancement
    • Status: Resolved
    • P4
    • Resolution: Fixed
    • 18
    • 19
    • hotspot
    • b05

    Description

      The original back-to-back if optimization added by JDK-8143542 relies on using split-if to nicely fold the dominated (and to be removed) if away afterwards in IGVN. However, it does not handle data dependencies correctly which could lead to crashes in rare cases (JDK-8275610). The fix for JDK-8275610 simply disables JDK-8143542 if there are data dependencies involved. This RFE aims to improve the back-to-back if optimization to also work correctly with data dependencies.

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          relates to

          Bug - A problem which impairs or prevents the functions of the product. JDK-8275610 C2: Object field load floats above its null check resulting in a segfault

          • P3 - Major loss of function.
          • Resolved

          Enhancement - null JDK-8143542 C2 doesn't eliminate identical checks

          • P3 - Major loss of function.
          • Resolved

          Bug - A problem which impairs or prevents the functions of the product. JDK-8297345 C2: SIGSEGV in PhaseIdealLoop::push_pinned_nodes_thru_region

          • P2 - Crashes, loss of data, severe memory leak.
          • Closed

          Enhancement - null JDK-8303970 C2 can not merge homogeneous adjacent two If

          • P4 - Minor loss of function, or other problem where easy workaround is present.
          • Open
          links to

          Commit Commit openjdk/jdk/8d1a1e83

          Review Review openjdk/jdk/6882

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              roland Roland Westrelin
              chagedorn Christian Hagedorn
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              Dates

                Created:
                Updated:
                Resolved: