JDK-8200303 : C2 should leverage profiling for lookupswitch/tableswitch
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: 11
  • Priority: P4
  • Status: Resolved
  • Resolution: Fixed
  • Submitted: 2018-03-27
  • Updated: 2020-08-12
  • Resolved: 2018-04-24
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JDK 11
11 b11Fixed
Related Reports
Relates :  
JDK-8229855 - C2 fails with assert(false) failed: bad AD file
Relates :  
JDK-8251458 - Parse::do_lookupswitch fails with "assert(_cnt >= 0) failed"
Relates :  
JDK-8209544 - AES encrypt performance regression in jdk11b11
Relates :  
JDK-8210389 - C2: assert(n->outcnt() != 0 || C->top() == n || n->is_Proj()) failed: No dead instructions after post-alloc
Relates :  
JDK-8229158 - make UseSwitchProfiling non-experimental or false by-default
Relates :  
JDK-8244301 - OpenJDK 11.0.2+9 crashes once in a while on C2 Compile task, compute_tree_cost(SwitchRange*, SwitchRange*, float)
Relates :  
JDK-8201366 - Improve output of dumpideal SA command for MachNodes
Relates :  
JDK-8058192 - compiler ignores lookupswitch and tableswitch branch profile numbers
Relates :  
JDK-8203196 - C1 emits incorrect code due to integer overflow in _tableswitch keys
Description
Same motivation as JDK-8058192 that seems to be used to cover graal.
Comments
Tests passed clean.
24-04-2018
According to Roland the failure is due to other problem: JDK-8201368.
24-04-2018
Test java/lang/Character/CheckScript.java in test/jdk failed with these changes. It passed with -XX:-UseSwitchProfiling
09-04-2018
Performance seems fine. As Roland pointed this optimization improved specjvm2008 Serial benchmark by 8-9%.
06-04-2018
Latest webrev which was tested: http://cr.openjdk.java.net/~roland/8200303/webrev.02/
05-04-2018
Latest testing passed.
05-04-2018
Failed to build on SPARC (PCH?): Undefined first referenced symbol in file log2f /workspace/build/solaris-sparcv9/hotspot/variant-server/libjvm/objs/parse2.o
27-03-2018
http://cr.openjdk.java.net/~roland/8200303/webrev.00/
27-03-2018