Phase 4 D3: alloc gate shape (env-gated)

docs/analysis/PHASE4_D3_ALLOC_GATE_SPECIALIZATION_1_DESIGN.md

@@ -216,6 +216,13 @@ HAKMEM_PROFILE=MIXED_TINYV3_C7_SAFE HAKMEM_ALLOC_GATE_SHAPE=1 \
   ./bench_random_mixed_hakmem 20000000 400 1
 ```
 
+### Results（2025-12-13, Release, 10-run）
+
+- Baseline（`HAKMEM_ALLOC_GATE_SHAPE=0`）: Mean **47.55M** ops/s, Median **48.08M**
+- Optimized（`HAKMEM_ALLOC_GATE_SHAPE=1`）: Mean **47.82M** ops/s, Median **47.84M**
+- Δ（Mean）: **+0.56%**（Median -0.5%）→ **NEUTRAL**
+- 動作確認: `HAKMEM_ALLOC_GATE_SHAPE=1` で `tiny_route_get()` 経由の `[REL_C7_ROUTE]` ログが消える（bypass を確認）
+
 ### Success Criteria
 
 **GO**: Mean gain >= +1.0%, Median >= +0.0%
@@ -231,6 +238,8 @@ HAKMEM_PROFILE=MIXED_TINYV3_C7_SAFE HAKMEM_ALLOC_GATE_SHAPE=1 \
 - **Freeze and archive** (default OFF, do not pursue)
 - Document regression cause, learn for future optimizations
 
+**Decision（この変更）**: **NEUTRAL**（default OFF の research box として保持）
+
 ## 期待値
 
 ### Performance Gain Estimation