JDK-8078113 : 8011102 changes may cause incorrect results.
  • Type: Bug
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: 7u80,8u60,9
  • Priority: P3
  • Status: Resolved
  • Resolution: Fixed
  • OS: generic
  • CPU: x86
  • Submitted: 2015-04-17
  • Updated: 2022-01-10
  • Resolved: 2015-04-18
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JDK 7 JDK 8 JDK 9
7u91Fixed 8u60Fixed 9 b64Fixed
Related Reports
Relates :  
JDK-8011102 - Clear AVX registers after return from JNI call
Relates :  
JDK-8279676 - Dubious YMM register clearing in x86_64 arraycopy stubs
Description
With 32 byte width vectorization the JVM produces wrong results under certain circumstances for x86_64.

The Vzeroupper instruction introduced in String.equals, String.compareTo and OptimizeFill intrinsic/stubs in the 8011102 changes is the cause.

For 32 byte vectorization, YMM registers are used by the hotspot compiler and the register allocator can allocate these across intrinsic methods.

Vzeroupper in the intrinsic is clobbering upper 16 bytes in all the other YMM registers that are not touched in these methods and so our customers are seeing unexpected results.
Comments
URL: http://hg.openjdk.java.net/jdk9/jdk9/hotspot/rev/5be37a65b137 User: lana Date: 2015-05-13 21:19:48 +0000
13-05-2015
URL: http://hg.openjdk.java.net/jdk9/hs-comp/hotspot/rev/5be37a65b137 User: kvn Date: 2015-04-18 02:47:14 +0000
18-04-2015
noreg-hard: the problem was reported to Intel by its customer who can't provide small test.
17-04-2015