JDK-8066649 : 8u backport for 8065618 is incorrect
  • Type: Bug
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: 8u40
  • Priority: P2
  • Status: Closed
  • Resolution: Fixed
  • OS: generic
  • CPU: generic
  • Submitted: 2014-12-04
  • Updated: 2015-02-10
  • Resolved: 2014-12-04
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JDK 7 JDK 8
7u80Fixed 8u40 b18Fixed
Related Reports
Relates :  
JDK-8065618 - C2 RA incorrectly removes kill projections
Description
The code in ifg.cpp is very different in 8u40. I prepared and pushed backport which is incorrect:

http://cr.openjdk.java.net/~kvn/8065618_8u/webrev/

In jdk9 the new code returns 'false' from separate method. In jdk8u there is no such method and corresponding code is inlined into build_ifg_physical().
The new code in 8u backport should not return but instead should guard the execution of the following code.
Comments
noreg-hard: I found this mistake by looking on code. The same as for 8065618, I was not able to write the test.
04-12-2014