JDK-8230015 : [instruction selector] generic vector operands support.
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: 14
  • Priority: P2
  • Status: Resolved
  • Resolution: Fixed
  • CPU: x86
  • Submitted: 2019-08-22
  • Updated: 2020-05-19
  • Resolved: 2020-05-19
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JDK 15
15Fixed
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Description
Currently, there are multiple instruction patterns for various vector operations which meagerly differ in vector lengths of input/output operands i.e. they have the same selector predication logic, matching pattern, data flow attribution (effect clause) over operands and a same number of operands. 

Different clauses of instruction pattern are compiled by ADLC to generate code catering to different stages in the compilation. This multiplicity in patterns for the same operation meagerly differing in vector operands translates to the generation of lots of extra functional and conditional logic which effectivity increases the libjvm.so size. 

Collapsing such multiple patterns to one pattern should not only help in size reduction of generated object files but also help in better maintenance and cleanup of AD files
Comments
All the related RFE linked to this JBS have been fixed. Marking this as resolved.
19-05-2020

http://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2019-November/036012.html
18-05-2020

Please note, post Rampdown Phase One of JDK 14, changing the Fix Version here to 15.
13-12-2019

Relevant mail thread: https://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2019-August/034822.html
23-08-2019

Patch to reduce vector operations over jdk-mainline has been posted for review. http://cr.openjdk.java.net/~jbhateja/genericVectorOperands/webrev.00
23-08-2019