JDK-8353041 : NeverBranchNode causes incorrect block frequency calculation
Type:Bug
Component:hotspot
Sub-Component:compiler
Affected Version:8,11,17,21,25
Priority:P3
Status:Resolved
Resolution:Fixed
OS:generic
CPU:generic
Submitted:2025-03-27
Updated:2025-05-14
Resolved:2025-04-09
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.
In
https://github.com/openjdk/jdk/pull/23962
it has been discussed that the C2 block frequency calculation needs to be adjusted.
Comments
Hi [~mbaesken]. No I wasn't planning on backporting it, as I didn't think it met the criteria, but if you feel differently go ahead and follow the openjdk process to get maintainer approvals.
14-05-2025
Hi [~dlong] do you plan to backport it to 21 and maybe 17 ?
09-05-2025
Changeset: 776e1cf1
Branch: master
Author: Dean Long <dlong@openjdk.org>
Date: 2025-04-09 20:06:49 +0000
URL: https://git.openjdk.org/jdk/commit/776e1cf1dfefd7cb1a0190ab71f71ad5ff25d0e4
09-04-2025
A pull request was submitted for review.
Branch: master
URL: https://git.openjdk.org/jdk/pull/24390
Date: 2025-04-02 19:51:37 +0000
02-04-2025
ILW = Incorrect computation of block frequency affecting performance, reproducible with infinite loop, no workaround = MMH = P3
28-03-2025
There is at least one place where this is known to show up, and that is with infinite loops that cause a NeverBranchNode to be used.
28-03-2025
ILW = Potential incorrect computation of block frequency affecting performance, found by code inspection; never showed up, no workaround = MLH = P4