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JIT: reconsider how to express managed pointer creation null checks #7882
Description
The JIT must track when managed pointer creation (via ldflda) will need an explicit null check. In most cases the check can be left implicit since the pointer is immediately dereferenced with a sufficiently small offset from the base object that no explicit check on the base is needed.
We may want to reconsider how the jit does this.
This tracking is currently done in Morph using the MorphAddressContext to model whether a dereference is imminent and what is known about the cumulative offset.
Relevant discussion in dotnet/coreclr#10956.
category:implementation
theme:morph
skill-level:expert
cost:medium
Activity
[-]JIT: reconsider how to express byref creation null checks[/-][+]JIT: reconsider how to express manged pointer creation null checks[/+][-]JIT: reconsider how to express manged pointer creation null checks[/-][+]JIT: reconsider how to express managed pointer creation null checks[/+]TIHan commentedon Nov 1, 2023
May be worth investigating for .NET 9.
AndyAyersMS commentedon Apr 14, 2024
Perhaps but without specific examples to study, it's hard to know if there's still a problem. I will leave this open for now but likely we'll just end up closing it.
AndyAyersMS commentedon Jun 7, 2026
Morph Address Context is gone: #127684