Phase 3 Closure & Phase 4 Preparation

Summary:
- Phase 3 optimization complete (cumulative +8.93%)
- D1 promoted to default (HAKMEM_FREE_STATIC_ROUTE=1, +2.19%)
- D2 frozen (NO-GO, -1.44% regression)
- Phase 4 instructions prepared (D3/Alloc Gate Specialization)

Results:
  B3 (Routing shape): +2.89%
  B4 (Wrapper split): +1.47%
  C3 (Static routing): +2.20%
  C1 (TLS prefetch): NEUTRAL (-0.34%, research box)
  C2 (Metadata cache): NEUTRAL (-0.45%, research box)
  D1 (Free route cache): +2.19% (now default)
  D2 (Wrapper env cache): NO-GO (-1.44%, frozen)
  MID_V3 fix: +13% (structural)

Total Phase 2-3 gain: ~8.93% (37.5M → 51M ops/s)

Updated:
- CURRENT_TASK.md: Phase 3 final results + D3 conditions
- ENV_PROFILE_PRESETS.md: Active optimizations listed
- PHASE3_CACHE_LOCALITY_NEXT_INSTRUCTIONS.md: Phase 3→4 transition
- PHASE4_ALLOC_GATE_SPECIALIZATION_NEXT_INSTRUCTIONS.md: D3 execution plan
- PHASE3_BASELINE_AND_CANDIDATES.md: Post-validation status

Next phase: Phase 4 D3 - Alloc Gate Specialization
- Requires: tiny_alloc_gate_fast self% ≥5% from perf
- Design SSOT: PHASE3_D3_ALLOC_GATE_SPECIALIZATION_1_DESIGN.md
- Execution: PHASE4_ALLOC_GATE_SPECIALIZATION_NEXT_INSTRUCTIONS.md

🤖 Generated with Claude Code

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

docs/analysis/PHASE3_BASELINE_AND_CANDIDATES.md

@@ -282,12 +282,14 @@ static inline void* tiny_alloc_gate_fast(size_t size)
 
 ## Step 3: Recommended Next Steps
 
-### Phase 3 D1: Free Path Route Cache ✅ GO（ENV opt-in）
+### Phase 3 D1: Free Path Route Cache ✅ ADOPT（PROMOTED TO DEFAULT）
 **Target**: `tiny_route_for_class()` の呼び出しを free path から削る
-**Result**: Mixed 10-run mean **+1.06%**（median は負ける回がある）
-**Decision**: ✅ GO だが **default 化は 20-run 確認待ち**
+**Result**: Mixed 20-run mean **+2.19%** / median **+2.37%**
+**Decision**: ✅ `MIXED_TINYV3_C7_SAFE` の default に昇格
 
-**ENV Gate**: `HAKMEM_FREE_STATIC_ROUTE=1`（default: 0）
+**ENV Gate**:
+- `HAKMEM_FREE_STATIC_ROUTE=0/1`（default: 0）
+- `MIXED_TINYV3_C7_SAFE` プリセットは `1` を default 注入（rollback は `0`）
 
 ---
 
@@ -321,7 +323,7 @@ static inline void* tiny_alloc_gate_fast(size_t size)
 | Phase      | Optimization                     | Expected Gain | Notes |
 |------------|----------------------------------|---------------|-------|
 | Baseline   | MID_V3=0 + B3+B4+C3              | -             | — |
-| **D1**     | Free route cache                 | +0〜+2%       | mean は勝ち、median 確認待ち（default OFF） |
+| **D1**     | Free route cache                 | +0〜+2%       | ✅ ADOPT（Mixed preset default ON） |
 | **D2**     | Wrapper env cache                | —             | NO-GO（freeze） |
 | **D3**     | Alloc gate specialization        | +0〜+2%       | perf で 5% 超なら着手 |