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  1. JDK
  2. JDK-8187601

Unrolling more when SLP auto-vectorization failed

    Details

    • Type: Enhancement
    • Status: Resolved
    • Priority: P4
    • Resolution: Fixed
    • Affects Version/s: 10
    • Fix Version/s: 10
    • Component/s: hotspot
    • Labels:
    • Subcomponent:
    • Resolved In Build:
      b31
    • CPU:
      generic
    • OS:
      linux

      Description

      For below Java code, which can't be auto-vectorized:
        public static void accessArrayConstants(int[] array) {
            for (int j = 0; j < 1024; j++) {
                array[0]++;
                array[1]++;
            }
        }
      Current C2 unrolls the loop to 8 times on X86 and 4 times on AArch64, which is limited by architecture's vector size. Get better performance, we should unroll more until reaching the unroll limitation.

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              • Assignee:
                zyao Zhongwei Yao
                Reporter:
                zyao Zhongwei Yao
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                Dates

                • Created:
                  Updated:
                  Resolved: