JDK-8297724 : Loop strip mining prevents some empty loops from being eliminated
  • Type: Bug
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: 11,17,20,21
  • Priority: P3
  • Status: Resolved
  • Resolution: Fixed
  • Submitted: 2022-11-28
  • Updated: 2024-03-06
  • Resolved: 2022-12-21
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JDK 21
21 b03Fixed
Related Reports
Relates :  
JDK-8327423 - C2: assert(locate_pre_from_main(main_head) == cl) failed: bad main loop
Relates :  
JDK-8315088 - C2: assert(wq.size() - before == EMPTY_LOOP_SIZE) failed: expect the EMPTY_LOOP_SIZE nodes of this body if empty
Description
Sometimes, the LSM safepoint is the only node keeping nodes in the inner counted loop alive. Without the LSM safepoint, some nodes from the inner counted loop alive would be eliminated and the inner loop would become empty and could be eliminated.
Comments
Changeset: 88bfe4d3 Author: Roland Westrelin <roland@openjdk.org> Date: 2022-12-21 14:46:57 +0000 URL: https://git.openjdk.org/jdk/commit/88bfe4d3bff5504bb6061d1484325dd6a55f06a2
21-12-2022
A pull request was submitted for review. URL: https://git.openjdk.org/jdk/pull/11699 Date: 2022-12-15 16:43:07 +0000
15-12-2022
ILW = missed optimization; sometimes; no workaround = MMH = P3
29-11-2022