JDK-8203197 : C2: consider all paths in loop body for loop predication
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: 11
  • Priority: P3
  • Status: Resolved
  • Resolution: Fixed
  • Submitted: 2018-05-15
  • Updated: 2024-04-25
  • Resolved: 2018-06-19
The Version table provides details related to the release that this issue/RFE will be addressed.

Unresolved : Release in which this issue/RFE will be addressed.
Resolved: Release in which this issue/RFE has been resolved.
Fixed : Release in which this issue/RFE has been fixed. The release containing this fix may be available for download as an Early Access Release or a General Availability Release.

To download the current JDK release, click here.
JDK 11
11 b19Fixed
Related Reports
Relates :  
JDK-8235584 - UseProfiledLoopPredicate fails with assert(_phase->get_loop(c) == loop) failed: have to be in the same loop
Relates :  
JDK-8231246 - C2 computes wrong trip count for loops
Relates :  
JDK-8331088 - Incorrect TraceLoopPredicate output
Relates :  
JDK-8240223 - Use consistent predicate order in and with PhaseIdealLoop::find_predicate
Relates :  
JDK-8328822 - C2: "negative trip count?" assert failure in profile predicate code
Relates :  
JDK-8240220 - IdealLoopTree::dump_head predicate printing is broken
Relates :  
JDK-8205515 - assert(opcode == Op_RangeCheck) failed: no other if variant here
Relates :  
JDK-8205574 - Loop predication "assert(f <= 1 && f >= 0) failed Incorrect frequency"
Description
Loop predication is only applied to predicates in the loop body that are always executed. Predicates are sometimes in a path in the loop body that's frequently but not always executed. In this case, applying loop predication would be beneficial.
Comments
URL: http://hg.openjdk.java.net/jdk/jdk/rev/5209d8a6303e User: roland Date: 2018-06-19 07:28:44 +0000
19-06-2018
All tests passed clean.
19-06-2018
webrev: http://cr.openjdk.java.net/~roland/8203197/webrev.01/
18-06-2018
Roland, please set the status to "In Progress". Thanks.
12-06-2018