JDK-8226473 : Release Note: More Registers Available When Running Without Compressed References on x86_64
- Type: Sub-task
- Component: hotspot
- Sub-Component: compiler
- Affected Version: 13
- Priority: P4
- Status: Closed
- Resolution: Fixed
- Submitted: 2019-06-20
- Updated: 2019-09-06
- Resolved: 2019-06-20
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Unresolved : Release in which this issue/RFE will be addressed.
Resolved: Release in which this issue/RFE has been resolved.
Fixed : Release in which this issue/RFE has been fixed. The release containing this fix may be available for download as an Early Access Release or a General Availability Release.
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| JDK 13 |
|---|
13Fixed  |
Description
When running with compressed references on x86_64, one of the CPU registers holds the heap base pointer to be used for references encoding/decoding. This register is not available for register allocation. Simple implementations before this release made this register unavailable (and thus unused) even if compressed references were disabled. In this release, the implementation was revised to put this unused register back into the available registers pool. Configurations with large heaps and/or `-XX:-UseCompressedOops` benefit from this improvement.