fix(gen-verilog): honest early-return lowering via a guard register - #1950
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Refs #1948 `return X;` lowered to a plain assignment with no exit: execution fell through and later statements overwrote the result -- a function ending in `return 0;` returned 0 on EVERY path. This is the runtime-divergence class behind the Verilog-vs-Zig/C test failures on the tri-net corpus. Every function body now carries `reg __t27_ret`: a return sets it and each remaining statement region is wrapped in `if (!__t27_ret)`. A disable-based lowering was tried and rejected: `disable` of the named body block corrupts recursive static functions (vvp hang in adaptive_retry's total_retry_time). The existing pretty if/else rewrite for guarded returns without an else is kept; the guard register covers the shapes it cannot (if/else-if chains, loops with returns). tri-net corpus: adaptive_routing drops from 8 failed asserts to 3 (the remainder is the [T; N] fn-param packing class); access_control newly passes; the 60-spec icarus gate is green. bridge.v regenerated under the new lowering. FROZEN_HASH resealed; only unit red is the pre-existing bitnet_layer iverilog test. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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…updated (#1958) * fix(gen-verilog): W458 keeps the legacy [N]T binding; unit contracts updated Refs #1948 Follow-up landing the two pieces auto-merge raced past in #1952/#1957: - The W458 array-param exclusion narrows to rust-style [T; N] primitives only: the legacy [N]T spelling keeps its module-array ROM binding contract (array_param_read_emitted asserts it) - nested_return_lowers_as_early_exit's discriminator includes the early-return guard assignment introduced by #1950 Unit suite back to a single pre-existing red (bitnet_layer iverilog). FROZEN_HASH resealed. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> * docs: NOW entries for the W458 follow-up Refs #1948 Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> --------- Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
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Refs #1948
return X;lowered to a plain assignment with no exit — later statements overwrote the result, so a fn ending inreturn 0;returned 0 on every path. This is the runtime-divergence class behind Verilog-vs-Zig/C failures.Every fn body now carries
reg __t27_ret; returns set it and each remaining statement region is wrapped inif (!__t27_ret). Adisable-based lowering was tried and rejected: it corrupts recursive static functions (vvp hang in adaptive_retry). The pretty if/else rewrite for else-less guarded returns is kept.tri-net corpus: adaptive_routing 8 → 3 failed asserts (rest is the [T; N] fn-param packing class); access_control newly passes; 60-spec gate green. bridge.v regenerated. Only unit red is pre-existing bitnet_layer. FROZEN_HASH resealed; NOW.md entries added.
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