# Session save — 2026-09-27: short-circuit AND/OR

`master` — suite **111/111**, tree clean except the user's uncommitted
`compiler/toto.mod` edit.

## Done today

**Short-circuit `AND`/`OR`** (task 1). Tag `v3-short-circuit`; details in
`docs/summary_short-circuit.md`.

- V3 used to evaluate both sides; gm2 and the compiler's own sources
  rely on short-circuit (~25 guard sites like
  `… AND (tform[t] = FAlias)`).
- Implemented by **deferring the RHS operand's code**: `QbeGen.DelayBegin`
  buffers it, `DelayEnd` restores output, `DelayFlush` replays it inside
  the branch; a **4-byte memory slot** (`Slot4`/`StoreW`/`LoadW`) merges
  the branch results (robust when the RHS spans blocks; a `phi` was not).
- `SimExpr` (OR) / `Term` (AND): `if a { r=1/0 } else { <RHS>; r=b }`.
- The `wip/short-circuit` branch (14 failing tests) was debugged — two
  bugs: `DelayFlush` popped the wrong index, and the `CopyOp`-only merge
  collapsed the branches to one operand — then merged and the branch
  deleted.

## In progress (task 2: full self-image)

The self-compiled V3 (`/tmp/M2self`) compiles a single file to a
**byte-identical `.ssa`**, but the **whole compiler source set** still
aborts (rc 134), now in the scanner's **`GetName`**
(`LexName ← GetIdent ← ProcTypeSection`) — a bounds trap in the
token-text copy loop (`0 ≤ i ≤ count` on the destination buffer).
Likely the caller's buffer descriptor header is wrong; needs more
diagnosis. (Earlier self-image aborts fixed: `Resolve`'s eager-`AND`
`tform[t]` guard → resolved by short-circuit.)

## Next

1. Diagnose the `GetName` bounds trap; iterate until `/tmp/M2self`
   compiles the whole set to a byte-identical `M2.ssa` (full fixpoint).
2. Cross-stage `FileIO` selection and `bootstrap/fixpoint.sh`
   (Stage1 gm2 → Stage2 V3 → Stage3 V3), with the stage-aware CR flag
   (`-m` for gm2, no `-m` for V3).

## Tags added

`v3-short-circuit` (merge + summary).