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  1. JDK
  2. JDK-8261671

X86 I2L conversion can be skipped for certain masked positive values

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    • b14
    • x86

    Description

      X86 I2L conversion can be skipped for certain masked positive values

      For the following expression:
       (long)(value & mask)
      Where value is of int type and mask is constant (power of two – 1), we can directly generate bzhi instruction to zero the upper bits
      Instead of doing an andl, followed by movslq

      Before:
      Benchmark Mode Cnt Score Error Units
      SkipIntToLongCast.skipMaskedSmallPositiveCast avgt 15 10.679 ± 1.496 ns/op


      After:
      Benchmark Mode Cnt Score Error Units
      SkipIntToLongCast.skipMaskedSmallPositiveCast avgt 15 7.870 ± 0.067 ns/op

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          relates to

          Bug - A problem which impairs or prevents the functions of the product. JDK-8263753 two new tests from JDK-8261671 fail with "Error. can not find ClassFileInstaller in test directory or libraries"

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

          Bug - A problem which impairs or prevents the functions of the product. JDK-8263904 compiler/intrinsics/bmi/verifycode/BzhiTestI2L.java fails on x86_32

          • 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-8268033 compiler/intrinsics/bmi/verifycode/BzhiTestI2L.java fails with "fatal error: Not compilable at tier 3: CodeBuffer overflow"

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

          Enhancement - null JDK-8248870 AArch64: I2L/L2I conversions can be skipped for masked positive values

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

          Commit Commit openjdk/jdk/4f4ca0e7

          Review Review openjdk/jdk/2590

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              sviswanathan Sandhya Viswanathan
              sviswanathan Sandhya Viswanathan
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                Created:
                Updated:
                Resolved: