[VM] Fix ref leak from incorrect MOVE bit on branch block args#23689
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benvanik merged 1 commit intoiree-org:mainfrom Mar 9, 2026
Merged
[VM] Fix ref leak from incorrect MOVE bit on branch block args#23689benvanik merged 1 commit intoiree-org:mainfrom
benvanik merged 1 commit intoiree-org:mainfrom
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isLastRealValueUse checked uses in ALL other blocks when deciding MOVE vs retain for branch operands. Uses in predecessor/definition blocks (prior control-flow edges) incorrectly prevented MOVE, causing ref leaks: retain incremented the ref count but no discard existed on the taken path to release it. Fix: only check uses in immediate successor blocks. Add a conservative guard for values that flow through a successor (liveIn && liveOut) to catch transitive escapes. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com> Signed-off-by: Jorn <jorn.tuyls@gmail.com>
benvanik
approved these changes
Mar 9, 2026
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isLastRealValueUsechecked uses in ALL other blocks when deciding MOVE vs retain for branch operands. Uses in predecessor/definition blocks (prior control-flow edges) incorrectly prevented MOVE, causing ref leaks: retain incremented the ref count but no discard existed on the taken path to release it.Fix: only check uses in immediate successor blocks. Add a conservative guard for values that flow through a successor (liveIn && liveOut) to catch transitive escapes.