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  1. JDK
  2. JDK-8247307

C2: Loop array fill stub routines are not called

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    • b04
    • generic
    • generic

    Description

      C2 has a loop optimization phase called intrinsify_fill [1]. It recognizes the code pattern of Java array initialization in a loop and generates calls to some array fill stub routines for better performance and smaller code size. But in latest jdk master (14/15), the calls to array fill stubs are not generated. Generated code shows the array initialization loops are automatically unrolled and vectorized.

      If this phase works, methods of java.util.Arrays.fill() should be optimized as well. We should check why this doen't work and try to fix it if this phase.

      [1] http://hg.openjdk.java.net/jdk/jdk/file/f1f88e6fad02/src/hotspot/share/opto/loopTransform.cpp#l3421

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          relates to

          Bug - A problem which impairs or prevents the functions of the product. JDK-8299179 ArrayFill with store on backedge needs to reduce length by 1

          • P3 - Major loss of function.
          • Resolved

          Enhancement - null JDK-8186027 C2: loop strip mining

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

          Enhancement - null JDK-8264063 Outer Safepoint poll load should not reference the head of inner strip mined loop.

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

          Bug - A problem which impairs or prevents the functions of the product. JDK-8263352 assert(use == polladr) failed: the use should be a safepoint polling

          • P3 - Major loss of function.
          • Resolved

          Bug - A problem which impairs or prevents the functions of the product. JDK-8283408 Fix a C2 crash when filling arrays with unsafe

          • P3 - Major loss of function.
          • Resolved

          Enhancement - null JDK-8275047 Optimize existing fill stubs for AVX-512 target

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

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              pli Pengfei Li
              pli Pengfei Li
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