Lower GT_RETURN_SUSPEND blocks to BBJ_RETURN#124177
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jakobbotsch merged 3 commits intodotnet:mainfrom Feb 10, 2026
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When the AsyncSuspend intrinsic is used we can end up with GT_RETURN_SUSPEND present in a block that is not `BBJ_RETURN`. That would happen for instance because of return merging due to ELT profiler hooks. Expand the lowering for this node to convert the block containing `GT_RETURN_SUSPEND` into a `BBJ_RETURN` block.
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Pull request overview
This PR updates JIT lowering to ensure blocks containing GT_RETURN_SUSPEND are properly treated as BBJ_RETURN blocks, addressing cases where return merging (e.g., due to ELT profiler hooks) can leave GT_RETURN_SUSPEND in a non-return block and break downstream assumptions.
Changes:
- Extend
Lowering::LowerReturnSuspendto scrub successor predecessor links and convert the containing block toBBJ_RETURN. - Adjust successor profile weights when removing outgoing flow and mark PGO data inconsistent when propagation would be required.
- Invalidate DFS tree after modifying control flow.
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
This was referenced Feb 9, 2026
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AndyAyersMS
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Feb 10, 2026
This was referenced Feb 10, 2026
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When the AsyncSuspend intrinsic is used we can end up with GT_RETURN_SUSPEND present in a block that is not
BBJ_RETURN. That would happen for instance because of return merging due to ELT profiler hooks.Expand the lowering for this node to convert the block containing
GT_RETURN_SUSPENDinto aBBJ_RETURNblock.Fix #124162