HowlFrame #90 Phase 3c: experimental if bytecode

[howlcipher]

Summary

Phase 3c teaches experimental -compile-hfir-bc to compile and run a small if by filling ControlEdges and emitting the existing JUMP_IF_FALSE and JUMP opcodes, the same pattern Phase 3b used for while.

LowerAST stores an if as a condition, a then-branch, and an optional else, and writes ControlEdges in that order. LowerToBytecode follows those successors. The relative jump offsets match the AST bytecode compiler. A then-only if emits JUMP_IF_FALSE and no JUMP. Missing or swapped control edges fail closed with one HFIR_BYTECODE_UNSUPPORTED diagnostic and no BCProgram.

Production -compile-bc is still runHFIRGate and then bytecode.CompileToBytecode on the AST. sleep still compiles on that flag and is still rejected by -compile-hfir-bc without an artifact. for does not gain control edges and still uses FOR_INIT / FOR_NEXT. while and defun keep the Phase 3a and Phase 3b behavior. There is no new opcode, capability, Wasm target, or module linker.

The model-adapter transport still rejects while and defun, so #88 stays closed. if stays a Phase-1 transport kind. The schema still has no control-edge field; decoding an if derives the successors from the validated roles. A payload that names control_edges is rejected. Localization publishes an if relation only when those successors match, and the published roles stay then and else.

tests/conformance/abi_v1/11_if.howl is the shared if_control case. hfir_bytecode, production bytecode, the interpreter, Go, and JavaScript print else, then, greater, and only. The false branches do not print.

#90 stays Partial. Journal: docs/journals/2026-09-30_lowered_hfir_abi_phase3c_if.md.

Test plan

• gofmt -l . is clean
• go vet ./...
• go test ./... (includes internal/hfir, the VM equivalence cases, the CLI lock that -compile-bc stays the AST, and tools/difftest if_control)

  

[howlcipher]

Phase 3c looks clean on the fence.

Experimental -compile-hfir-bc gets if through ControlEdges (condition / then / optional else) on the existing JUMP_IF_FALSE / JUMP path. Production -compile-bc stays AST (runHFIRGate → CompileToBytecode); the sleep lock in TestCompileBcStaysASTWhileHfirBcRunsIf is the right guard. for stays empty. No new opcode, no new cap, no Wasm, no linker/module work. #88 stays closed (while/defun still off transport; no control_edges field). #90 stays Partial.

Hard nos clean. CI build green on d241e3f.

Okabe: undraft + squash-merge when ready. Don’t flip #90 to Done on merge.