JDK-8181211 : C2: Use profiling data to optimize on/off heap unsafe accesses
- Type: Enhancement
- Component: hotspot
- Sub-Component: compiler
- Affected Version: 9,10
- Priority: P3
- Status: Resolved
- Resolution: Fixed
- Submitted: 2017-05-30
- Updated: 2019-07-17
- Resolved: 2017-06-15
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| JDK 10 |
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10 b21Fixed  |
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Description
JDK-8176506 changed the unsafe access logic to be much more conservative for accesses that are not known to be on or off heap. Using profiling of arguments of Unsafe.put* and Unsafe.get*, C2 can often speculate whether an access is on heap or off heap. Better code generation of loops of unsafe accesses should compensate the cost of the extra null check/assert.