RFR(S): 8227463: [lworld] Non-optimal code generation for array properties check

Tobias Hartmann tobias.hartmann at oracle.com
Wed Jul 10 08:16:33 UTC 2019


Hi,

please review the following patch that optimizes code generation for the array properties check:
https://bugs.openjdk.java.net/browse/JDK-8227463
http://cr.openjdk.java.net/~thartmann/8227463/webrev.00/

Before:
  Compressed oops:
  0x00007f1eb9177c92: mov 0x8(%r12,%r10,8),%r11d
  0x00007f1eb9177c97: mov %r11d,%r8d
  0x00007f1eb9177c9a: test $0x40000000,%r8d

  No compressed oops:
  0x00007f893d1662dd: mov 0x8(%r10),%r11
  0x00007f893d1662e1: movabs $0x4000000000000000,%r8
  0x00007f893d1662eb: and %r8,%r11
  0x00007f893d1662ee: test %r11,%r11

After:
  Compressed oops:
  0x00007fef69177a92: testl $0x40000000,0x8(%r12,%r10,8)

  No compressed oops:
  0x00007fcd7d1660dd: movabs $0x4000000000000000,%r11
  0x00007fcd7d1660e7: test %r11,0x8(%r10)

Thanks,
Tobias


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