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  1. JDK
  2. JDK-8154826

AArch64: take better advantage of base + shifted offset addressing mode

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Details

    • Bug
    • Status: Resolved
    • P4
    • Resolution: Fixed
    • 9
    • 9
    • hotspot
    • None
    • b120
    • aarch64

    Description

      The aarch64 port implicitly transforms:
      (AddP base (AddP base address (LShiftL index con)) offset)
      into:
      (AddP base (AddP base offset) (LShiftL index con))
      in the ad file to embed the shift (and possibly and i2l conversion) into the addressing mode of a memory operation. Exposing that transformation in the ideal graph allows:

      - (AddP base offset) to be scheduled (for instance outside a loop)
      - multiple identical (AddP base offset) can be commoned
      - (LShiftL index con) can be cloned during matching so that each memory access has its own

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          relates to

          Bug - A problem which impairs or prevents the functions of the product. JDK-8267689 [8u] [aarch64] Crash due to bad shift in indirect addressing mode

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

          Enhancement - null JDK-8068350 ARM: C2: matcher causes sub-optimal code for ARM

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

          Bug - A problem which impairs or prevents the functions of the product. JDK-8270533 AArch64: size_fits_all_mem_uses should return false if its output is a CAS

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

          Enhancement - null JDK-6217251 Reassociate array address expression when profitable: (p+v)+k becomes (p+k)+v

          • P3 - Major loss of function.
          • Open

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              roland Roland Westrelin
              roland Roland Westrelin
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              Dates

                Created:
                Updated:
                Resolved: