JDK-8260943 : Revisit vectorization optimization added by 8076284
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: 17
  • Priority: P4
  • Status: Open
  • Resolution: Unresolved
  • Submitted: 2021-02-02
  • Updated: 2021-02-02
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tbdUnresolved
Related Reports
Relates :  
JDK-8251994 - VM crashed running TestComplexAddrExpr.java test with -XX:UseAVX=X
Description
JDK-8251994 changes excluded optimization added by JDK-8076284. It is incomplete and buggy in current state.

Using unrolling and cloning information to vectorize is interesting idea but as I see it is not complete. Even if pack_parallel() method is able create packs, they are all removed by filter_packs() method.  And additionally the cases listed in RFR are vectorized without hoisting loads and pack_parallel - I verified it:
https://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2015-April/017645.html

This code should be revisited to be useful or removed.