JIT: Handle memory conservatively in handler blocks in VN #106274
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SSA does not model memory SSA faithfully inside try clauses. To model it faithfully we would need to make all intermediate memory states in the try block visible to the handler block. Doing so would require teaching SSA about all nodes that define memory, and introduce a bunch of new memory SSA states for EH constructs. Instead of doing that this PR makes VN treat any handler block with multiple incoming memory states (meaning that memory changed during the try) conservatively. The diffs seem small enough; we can consider a more elaborate fix in .NET 10. Fix dotnet#86112
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Aug 12, 2024
This was referenced Aug 12, 2024
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SSA does not model memory SSA faithfully inside try clauses. To model it
faithfully we would need to make all intermediate memory states in the
try block visible to the handler block. Doing so would require teaching
SSA about all nodes that define memory, and introduce a bunch of new
memory SSA states for EH constructs.
Instead of doing that this PR makes VN treat any handler block with
multiple incoming memory states (meaning that memory changed during the
try) conservatively. The diffs seem small enough; we can consider a more
elaborate fix in .NET 10.
Fix #86112