25 lines
987 B
Markdown
25 lines
987 B
Markdown
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# Scope & Assumptions (2025-09-19)
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## Current Execution Lines
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- In-scope: PyVM (semantic reference), LLVM/llvmlite (AOT/EXE harness)
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- Out-of-scope: Cranelift JIT and Rust MIR Interpreter (maintenance only during Phase‑15)
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## MIR14 Policy
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- PHI-off at MIR: merges are represented by per-predecessor edge copies
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- PHI synthesis is delegated to the LLVM harness (block-head PHIs, typed incoming)
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- Verifier runs with `verify_allow_no_phi()` and edge-copy checks
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## Parity & Evaluation
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- Parity: PyVM vs LLVM output equivalence on curated smokes
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- Metrics: runtime, startup time, memory; report only for PyVM/LLVM lines
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- Tracing: `NYASH_LLVM_TRACE_PHI=1`, IR dump `NYASH_LLVM_DUMP_IR=...`
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## Toggles
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- `NYASH_MIR_NO_PHI=1` (default) — PHI disabled at MIR
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- Dev-only PHI-on: build with `--features phi-legacy` and set `NYASH_MIR_NO_PHI=0`
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## Notes
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- Figures and text must avoid implying MIR-side PHI placement as default.
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- Reference canonical specs live under `docs/reference/`.
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