On Mon, 3 Nov 2025 14:12:55 GMT, Manuel Hässig <[email protected]> wrote:

> ## Problem Analysis
> 
> The stress test `compiler/valhalla/inlinetypes/TestAcmpWithUnstableIf.java`, 
> which uses the `StressUnstableIfTrap` flag, failed intermittently with the 
> assert "no node with a side effect" during C2 compilation. I tracked down the 
> origin of the failure to the raw store of the unstable if trap stress counter 
> that was missing a memory edge to the backedge phi and thus had no side 
> effect in the loop, which lead to the aforementioned assert. During parsing, 
> the missing memory edge gets discarded with as vestigial parsing state when 
> `do_if()` ends up `stopped()`. However, the effect of the stress counter 
> should still be wired back into the backedge since it will be incremented in 
> the next iteration.
> 
> ## Patch Description
> 
> To prevent the stress counters memory state being lost to `PreserveJVMState`, 
> I pass it to the caller over an out-parameter and `set_memory` with that 
> node, similar to what is already done for control. This is only necessary for 
> the two last invocation of `do_if()` in `do_acmp()` where they are actually 
> allowed to trap. Further, this PR reenables `StressUnstableIfTrap` in 
> `compiler/valhalla/inlinetypes/TestAcmpWithUnstableIf.java`.
> 
> ## Testing
> 
> - [x] tier1,tier2,tier3 plus internal stress testing

This pull request has now been integrated.

Changeset: a0ec2441
Author:    Manuel Hässig <[email protected]>
Committer: Christian Hagedorn <[email protected]>
URL:       
https://git.openjdk.org/valhalla/commit/a0ec2441494f9e77b3a8a3db90358db239b27b4d
Stats:     85 lines in 4 files changed: 77 ins; 2 del; 6 mod

8367244: [lworld] C2 compilation fails with assert "no node with a side effect"

Reviewed-by: chagedorn

-------------

PR: https://git.openjdk.org/valhalla/pull/1716

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