refactor: extract float NaN/subnormal helpers (H-1.4, H-1.5)#78
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refactor: extract float NaN/subnormal helpers (H-1.4, H-1.5)#78
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…, H-1.5) Extract inline NaN canonicalization and subnormal checks into reusable helper functions: F32/F64_CANONICAL_NAN constants, is_f32/f64_subnormal(), canonicalize_f32/f64(). Pure refactor, no behavioral change. Makes the float constant folding code auditable against hazards H-1.4 (non-canonical NaN) and H-1.5 (subnormal flushing). Trace: H-1 Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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Superseded by PR #79 which includes these float helper changes plus SC→REQ traceability links. |
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Summary
Extract inline float NaN canonicalization and subnormal checks into reusable helper functions. Pure refactor — no behavioral change.
New helpers
F32_CANONICAL_NAN/F64_CANONICAL_NAN— WebAssembly spec canonical NaN constantsis_f32_subnormal()/is_f64_subnormal()— subnormal detectioncanonicalize_f32()/canonicalize_f64()— returns canonical NaN bits if NaN, else result bitsReplaces inline patterns across 8 arithmetic fold sites (f32/f64 add/sub/mul/div).
Why
Makes float constant folding code auditable against STPA hazards H-1.4 (non-canonical NaN production) and H-1.5 (subnormal flushing on ARM). Reviewer can verify correctness by inspecting 6 helper functions instead of 8 scattered match arms.
Test plan
cargo test --release— all tests pass unchanged🤖 Generated with Claude Code