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  1. JDK
  2. JDK-8255838

Use 32-bit immediate movslq in macro assembler if 64-bit value fits in 32 bits on x86_64

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Details

    • Enhancement
    • Resolution: Fixed
    • P4
    • 16
    • 16
    • hotspot
    • None
    • b23

    Description

      Currently, Macro::Assembler(Address dst, intprt_t src) on x64 uses an intermediate scratch register to store the 64-bit immediate.

      But, if the value fits into 32-bits, we can also explicitly use the 32-bit immediate overload, which saves an instruction and a register use.

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        Issue Links

          relates to

          Enhancement - null JDK-8319406 x86: Shorter movptr(reg, imm) for 32-bit immediates

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

          Enhancement - null JDK-8255921 Use 'nop' to replace 'mov' when patching instructions

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

          Commit Commit openjdk/jdk/160759ce

          Review Review openjdk/jdk/1038

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              jvernee Jorn Vernee
              jvernee Jorn Vernee
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              Dates

                Created:
                Updated:
                Resolved: