P5.7 Step A: VM is the sole comptime evaluator at emit-time + type-fn sites (no fallback)

Remove the comptime_flat/need_vm gate and the vm_result-orelse-legacy
fallback from emit_llvm.zig (runComptimeSideEffects + emitGlobals const-init)
and comptime.zig (runComptimeTypeFunc). The comptime VM now always runs;
a bail is always a build-gating diagnostic, never a fallback. Delete the
now-moot entryNeedsVm. runComptimeSideEffects drops the Interpreter entirely
(VM writes #run output direct to fd 1); emitGlobals keeps a fresh interp_inst
only as the valueToLLVMConst materialization context (the regToValue bridge,
removed with interp.zig in a later step).

#insert (evalComptimeString) still routes through the legacy interp — deferred
until interp.zig deletion.

Reconcile 1654: the comptime asm-global #run now reports the VM's clean dlsym
bail instead of the legacy CannotEvalComptime wrapper (exit still 1).

501/501 unit + 706/0 corpus.

current/CHECKPOINT-COMPILER-API.md

@@ -431,6 +431,38 @@ when reached (sentinels or accessor fns; see the design doc Risks).
   `List` growth; orthogonal, see `current/CHECKPOINT-METATYPE.md`.)
 
 ## Log
+- **P5.7 Step A — the flip: VM is the SOLE comptime evaluator at the emit-time + type-fn sites; NO fallback
+  (2026-06-19).** Removed the `if (self.comptime_flat or need_vm)` gate + the `vm_result orelse fallback`
+  legacy-interp blocks from `emit_llvm.zig` (`runComptimeSideEffects` AND the const-init path in `emitGlobals`)
+  and from `comptime.zig` `runComptimeTypeFunc` (type-fn). The VM now ALWAYS runs; a bail is ALWAYS a
+  build-gating diagnostic (`comptime_vm.last_bail_reason`), never a fallback. Deleted `emit_llvm.entryNeedsVm`
+  (moot — every entry runs on the VM now). `runComptimeSideEffects` no longer creates an `Interpreter` at all
+  (VM writes `#run` `print` output direct to fd 1 via host-FFI); `emitGlobals` keeps a fresh `interp_inst` ONLY
+  as the helper context `valueToLLVMConst` uses to materialize the VM's result Value (it evaluates nothing) —
+  that's the `regToValue` bridge, removed in Step C with `interp.zig`. **`#insert` (`evalComptimeString`) still
+  uses the legacy interp** — intentionally deferred to Step C (interp.zig still exists); it only needs the
+  evaluator to bail without crashing (0737's real error is a lowering-time visibility diagnostic). The
+  `comptime_flat*` LLVMEmitter fields are now set-but-unused (harmless; cosmetic cleanup later). **Snapshot
+  reconcile:** only `1654` churned — the asm-global `#run` now reports the VM's clean `comptime init of
+  'COMPUTED' failed: comptime extern call: symbol not found via dlsym …` instead of the legacy
+  `CannotEvalComptime (op=call: …)` wrapper (exit still 1); regenerated scoped via `-Dname`. `1179`/`1180`
+  unchanged (the VM-strict `comptime type construction failed:` wording already matched). **501/501 unit +
+  706/0 corpus** (one gate now — `-Dcomptime-flat` is moot but still accepted). NEXT: Step B — delete the
+  `#compiler` attribute (parse+lower) + the `compiler_call` IR op + `compiler_hooks.zig`.
+- **P5.7 Step 0 — strict sweep CLEAN; zero VM gaps to port (2026-06-19).** Gating prerequisite for deleting the
+  legacy fallback. Confirmed both gates 706/0 + 501/501 unit (gate-OFF and `-Dcomptime-flat`). Then ran every
+  corpus example (706) under `SX_COMPTIME_FLAT_STRICT=1` (VM, NO fallback) via `.sx-tmp/strict_sweep.sh` —
+  `sx run` (JIT), `sx build` (aot/bundle), or `sx ir --target` (cross-arch). Only **3** examples emit a VM-bail
+  signature, ALL expected-failures (strict exit == expected exit), NONE a real gap: **1179**
+  (`enum has no variants`) + **1180** (`duplicate variant name`) render the SAME `comptime type construction
+  failed:` diagnostic the VM-strict path in `comptime.zig` already emits (no snapshot churn at the flip); **1654**
+  (asm-global called at `#run`) — the VM bails cleanly via `callHostExtern` dlsym ("symbol not found … target-
+  specific binding called at compile time?"), only its `.stderr` WORDING changes (legacy `CannotEvalComptime
+  (op=call…)` → VM strict form) and must be reconciled at the flip. **Key conclusion (the prompt's flagged risk):
+  no SUCCESSFUL corpus example relies on the legacy VM→legacy fallback** — every passing example runs natively on
+  the VM; the only fallback users are the 3 expected-failures above. Removing the fallback is therefore safe. No
+  ops to port before flipping. NEXT: make `-Dcomptime-flat` permanent + delete the fallback (emit_llvm both sites
+  + comptime.zig) + remove `entryNeedsVm`, reconcile 1654.
 - **P5.8 (partial) — real-project validation: m3te + distribution build with the new pipeline (2026-06-19).**
   Acceptance test for the sx-driven build pipeline. **m3te** (`~/projects/m3te`, an SDL3 match-3 game): migrated
   its `build.sx` off the deleted API — `configure_build :: ()` → `() abi(.compiler)`, `opts.set_post_link_callback(