JDK-8038297 : Avoid placing CTI immediately following cbcond instruction on T4
  • Type: Bug
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: hs22
  • Priority: P3
  • Status: Resolved
  • Resolution: Fixed
  • OS: generic
  • CPU: sparc
  • Submitted: 2014-03-25
  • Updated: 2019-09-13
  • Resolved: 2014-04-11
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8u20Fixed 9 b11Fixed
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Description
Code generated for T4 and related SPARC processors should avoid placing Control Transfer Instructions [CTI] such as call and retl immediately following a cbcond instruction.

Comments
I asked Igor to look on this. He recently worked on an other cbcond problem: 8035283.
26-03-2014

Looks like it is reasonable request. Richard, can you attach your microbenchmark to the bug report so we can measure the same performance difference?
25-03-2014

Is it the problem only on T4? Or also on all newer T-SPARC?
25-03-2014

Richard, can you point any documents about this? There was only restriction on placing an other cbcond instruction after first.
25-03-2014