diff --git a/CURRENT_TASK.md b/CURRENT_TASK.md
index 8ea2c97b..378a4a24 100644
--- a/CURRENT_TASK.md
+++ b/CURRENT_TASK.md
@@ -1,5 +1,87 @@
 # Current Task
 
+## ✅ Phase 184: JoinIR If Lowering Mainline (Completed - 2025-12-04)
+
+**Status**: ✅ **All Tasks Completed** → Phase 185+ Ready
+
+**Key Achievement**: If lowering infrastructure now has dedicated JOINIR_IF_TARGETS table, separate from loop lowering (JOINIR_TARGETS). 6 representative functions established with default-enabled mainline paths.
+
+### Completed Tasks
+
+✅ **Task 1**: If lowering inventory
+- Created comprehensive inventory of all If lowering functions
+- Identified 6 representative functions (4 test + 2 production)
+- Document: `docs/private/roadmap2/phases/phase-184/if_lowering_inventory.md`
+
+✅ **Task 2**: JOINIR_IF_TARGETS table and is_if_mainline_target()
+- Implemented JOINIR_IF_TARGETS in `src/mir/join_ir_vm_bridge_dispatch/targets.rs`
+- Added is_if_lowered_function() for table lookup
+- Exported via module public API
+
+✅ **Task 3**: If lowering integration
+- Updated is_if_mainline_target() to use table (src/mir/join_ir/lowering/mod.rs)
+- Updated is_joinir_if_toplevel_target() to check table first
+- Maintained Loop/If separation (Phase 33-9.1 responsibility principle)
+
+✅ **Task 4**: Representative paths verified
+- IfSelectTest.test/1: ✅ Select lowering working
+- IfSelectLocalTest.main/0: ✅ Local variable pattern working
+- IfMergeTest.simple_true/0, simple_false/0: ✅ Multiple variable patterns working
+
+✅ **Task 5**: Documentation updated
+- Phase 184 README: Complete with architecture diagrams
+- CURRENT_TASK.md: Updated with completion status
+
+### Implementation Summary
+
+**JOINIR_IF_TARGETS Table** (6 functions):
+1. `IfSelectTest.test/1` - Simple return pattern
+2. `IfSelectLocalTest.main/0` - Local variable pattern
+3. `IfMergeTest.simple_true/0` - Multiple variables (IfMerge)
+4. `IfMergeTest.simple_false/0` - Multiple variables (IfMerge)
+5. `JsonShapeToMap._read_value_from_pair/1` - Stage-1 production
+6. `Stage1JsonScannerBox.value_start_after_key_pos/2` - Stage-B production
+
+**Architecture Impact**:
+- JOINIR_TARGETS (Loop) and JOINIR_IF_TARGETS (If) are now clearly separated
+- 1関数につき1 lowering の原則を完全実装
+- SSOT (Single Source of Truth) for If lowering targets established
+
+**Modified Files**:
+- `src/mir/join_ir_vm_bridge_dispatch/targets.rs` (+75 lines)
+- `src/mir/join_ir_vm_bridge_dispatch/mod.rs` (exports)
+- `src/mir/join_ir/lowering/mod.rs` (table integration)
+
+### Known Issues (Non-blocking)
+
+1. **Double-invocation in strict mode**: NYASH_JOINIR_STRICT=1 can panic even when lowering succeeds (skeleton + lowering passes). Workaround: use NYASH_JOINIR_DEBUG=1 instead.
+2. **Test output formatting**: Tests show "RC: 0" instead of expected print output (unrelated to If lowering infrastructure).
+
+### Verification Commands
+
+```bash
+# Basic verification (default JoinIR ON)
+NYASH_JOINIR_DEBUG=1 ./target/release/hakorune apps/tests/joinir_if_select_simple.hako
+# Expected: [try_lower_if_to_joinir] ✅ Select lowering used for IfSelectTest.test/1
+
+# IfMerge pattern
+NYASH_JOINIR_DEBUG=1 ./target/release/hakorune apps/tests/joinir_if_merge_simple.hako
+# Expected: IfMerge lowering messages
+
+# Build verification
+cargo build --release
+# Expected: Success with only warnings (no errors)
+```
+
+### Next Steps: Phase 185+
+
+1. **Expand JOINIR_IF_TARGETS**: Add more selfhost functions as they stabilize
+2. **Address double-invocation**: Refactor if_form.rs if needed
+3. **Stage-1 rollout**: Automatic inclusion of Stage1* prefixed functions
+4. **Metrics tracking**: If lowering success rate monitoring
+
+---
+
 ## 🎉 Phase 183: JoinIR Default ON & Legacy Toggle (Completed - 2025-12-04)
 
 **Status**: ✅ **All Tasks Completed** → Phase 184 Ready
diff --git a/src/mir/join_ir/lowering/mod.rs b/src/mir/join_ir/lowering/mod.rs
index 105af570..ad8322b3 100644
--- a/src/mir/join_ir/lowering/mod.rs
+++ b/src/mir/join_ir/lowering/mod.rs
@@ -94,12 +94,14 @@ pub fn is_loop_mainline_target(name: &str) -> bool {
     is_loop_lowered_function(name)
 }
 
-/// Phase 80: JoinIR 本線化対象（If）の判定
+/// Phase 80/184: JoinIR 本線化対象（If）の判定
 ///
 /// `joinir_core_enabled()=true` の時、これらの関数の if/else は
 /// 必ず JoinIR → MIR 経路を本線として試行します。
+///
+/// Phase 184: JOINIR_IF_TARGETS テーブルからの参照に変更
 pub fn is_if_mainline_target(name: &str) -> bool {
-    is_joinir_if_toplevel_target(name)
+    crate::mir::join_ir_vm_bridge_dispatch::is_if_lowered_function(name)
 }
 
 /// Phase 80: Core ON 時に JoinIR を本線として試行すべきか判定
@@ -126,21 +128,33 @@ pub fn should_panic_on_joinir_failure(func_name: &str, is_loop: bool) -> bool {
     should_try_joinir_mainline(func_name, is_loop)
 }
 
-/// Phase 61-4: ループ外 If の JoinIR 対象関数判定
+/// Phase 61-4/184: ループ外 If の JoinIR 対象関数判定
 ///
 /// HAKO_JOINIR_IF_TOPLEVEL=1 有効時に、ループ外 if の JoinIR 経路を試行する関数。
-/// 段階的に対象を拡大するため、最小限のホワイトリストから開始。
+/// Phase 184: JOINIR_IF_TARGETS テーブルに統一（SSOT化）
 ///
-/// ## 対象関数
+/// ## 対象関数（テーブル管理）
 /// - IfSelectTest.*: テスト専用関数群
+/// - IfMergeTest.*: 複数変数テスト（Phase 33-7）
 /// - IfToplevelTest.*: ループ外 if テスト専用（Phase 61-4）
-/// - JsonShapeToMap._read_value_from_pair/1: Phase 33-4 で検証済み
+/// - JsonShapeToMap._read_value_from_pair/1: Phase 33-4 Stage-1 実用関数
+/// - Stage1JsonScannerBox.value_start_after_key_pos/2: Phase 33-4 Stage-B 実用関数
 ///
 /// ## 使用方法
-/// if_form.rs から呼び出され、関数名がホワイトリストに含まれる場合のみ
+/// if_form.rs から呼び出され、関数名がテーブルに含まれる場合のみ
 /// JoinIR 経路を試行する。
+///
+/// Phase 184: テーブル参照に変更（プレフィックス判定は併用）
 pub fn is_joinir_if_toplevel_target(name: &str) -> bool {
-    // Test prefixes (always enabled)
+    // Phase 184: JOINIR_IF_TARGETS テーブルから参照（exact match）
+    if crate::mir::join_ir_vm_bridge_dispatch::JOINIR_IF_TARGETS
+        .iter()
+        .any(|t| t.func_name == name)
+    {
+        return true;
+    }
+
+    // Test prefixes (backward compatibility - allows any test function)
     if name.starts_with("IfSelectTest.")
         || name.starts_with("IfToplevelTest.")
         || name.starts_with("IfMergeTest.")
@@ -148,12 +162,7 @@ pub fn is_joinir_if_toplevel_target(name: &str) -> bool {
         return true;
     }
 
-    // Explicit approvals (Phase 33-4 verified)
-    matches!(
-        name,
-        "JsonShapeToMap._read_value_from_pair/1"
-            | "Stage1JsonScannerBox.value_start_after_key_pos/2"
-    )
+    false
 }
 
 /// Phase 33-7: Try to lower if/else to JoinIR Select/IfMerge instruction
diff --git a/src/mir/join_ir_vm_bridge_dispatch/mod.rs b/src/mir/join_ir_vm_bridge_dispatch/mod.rs
index 23ec7d25..f6b3c1ae 100644
--- a/src/mir/join_ir_vm_bridge_dispatch/mod.rs
+++ b/src/mir/join_ir_vm_bridge_dispatch/mod.rs
@@ -20,7 +20,9 @@ use lower_only_routes::{
     try_run_stage1_usingresolver, try_run_stageb_body, try_run_stageb_funcscanner,
 };
 use targets::find_joinir_target;
-pub use targets::{JoinIrBridgeKind, JoinIrTargetDesc, JOINIR_TARGETS};
+pub use targets::{
+    is_if_lowered_function, JoinIrBridgeKind, JoinIrTargetDesc, JOINIR_IF_TARGETS, JOINIR_TARGETS,
+};
 
 use crate::mir::MirModule;
 
diff --git a/src/mir/join_ir_vm_bridge_dispatch/targets.rs b/src/mir/join_ir_vm_bridge_dispatch/targets.rs
index 9e19cd43..6a7138d6 100644
--- a/src/mir/join_ir_vm_bridge_dispatch/targets.rs
+++ b/src/mir/join_ir_vm_bridge_dispatch/targets.rs
@@ -25,15 +25,16 @@ pub struct JoinIrTargetDesc {
     pub default_enabled: bool,
 }
 
-/// JoinIR ブリッジ対象テーブル（SSOT）
+/// JoinIR ループ lowering 対象テーブル（SSOT）
 ///
 /// Phase 32 L-4: 全対象関数を一覧化し、Exec/LowerOnly の区分を明示する。
 /// Phase 82: このテーブルが唯一の SSOT。is_loop_lowered_function() はここから参照。
 /// Phase 182: representative paths 対応（3 upgrades - LOOP ONLY）
+/// Phase 184: Loop/If 分離を明文化（If は JOINIR_IF_TARGETS へ）
 ///
 /// **重要**: このテーブルは LOOP lowering 専用です。
 /// If lowering の関数を追加すると、is_loop_lowered_function() で除外され、
-/// if-lowering が機能しなくなります。If 関数は is_joinir_if_toplevel_target() で管理。
+/// if-lowering が機能しなくなります。If 関数は JOINIR_IF_TARGETS で管理。
 ///
 /// | 関数 | Kind | デフォルト有効 | 備考 |
 /// |-----|------|---------------|------|
@@ -89,3 +90,81 @@ pub(crate) fn find_joinir_target(module: &MirModule) -> Option<&'static JoinIrTa
         .iter()
         .find(|target| module.functions.contains_key(target.func_name))
 }
+
+// ============================================================================
+// Phase 184: JoinIR If Lowering Targets (Separate from Loop Targets)
+// ============================================================================
+
+/// JoinIR If lowering 対象テーブル（SSOT）
+///
+/// Phase 184: Loop lowering（JOINIR_TARGETS）と分離した If lowering 専用テーブル。
+/// Phase 182 で判明した設計制約（JOINIR_TARGETS は Loop 専用）に基づく責務分離。
+///
+/// **責務**:
+/// - If/Else → Select/IfMerge lowering の対象関数を一覧化
+/// - Loop lowering と独立して管理（1関数につき1 lowering の原則）
+///
+/// **使用箇所**:
+/// - `is_if_mainline_target()`: Core ON 時の本線化判定
+/// - `try_lower_if_to_joinir()`: If lowering 試行時のホワイトリスト
+///
+/// | 関数 | Kind | デフォルト有効 | 備考 |
+/// |-----|------|---------------|------|
+/// | IfSelectTest.test/1 | Exec | Yes | Phase 33-2/33-3 simple return pattern |
+/// | IfSelectLocalTest.main/0 | Exec | Yes | Phase 33-10 local variable pattern |
+/// | IfMergeTest.simple_true/0 | Exec | Yes | Phase 33-7 multiple variables (IfMerge) |
+/// | IfMergeTest.simple_false/0 | Exec | Yes | Phase 33-7 multiple variables (IfMerge) |
+/// | JsonShapeToMap._read_value_from_pair/1 | Exec | Yes | Phase 33-4 Stage-1 実用関数 |
+/// | Stage1JsonScannerBox.value_start_after_key_pos/2 | Exec | Yes | Phase 33-4 Stage-B 実用関数 |
+///
+/// Phase 184 設計ドキュメント:
+/// - docs/private/roadmap2/phases/phase-184/if_lowering_inventory.md
+/// - docs/private/roadmap2/phases/phase-184/README.md
+pub const JOINIR_IF_TARGETS: &[JoinIrTargetDesc] = &[
+    // Test functions (Phase 33 series)
+    JoinIrTargetDesc {
+        func_name: "IfSelectTest.test/1",
+        kind: JoinIrBridgeKind::Exec,
+        default_enabled: true, // Simple return pattern (Phase 33-2/33-3)
+    },
+    JoinIrTargetDesc {
+        func_name: "IfSelectLocalTest.main/0",
+        kind: JoinIrBridgeKind::Exec,
+        default_enabled: true, // Local variable pattern (Phase 33-10)
+    },
+    JoinIrTargetDesc {
+        func_name: "IfMergeTest.simple_true/0",
+        kind: JoinIrBridgeKind::Exec,
+        default_enabled: true, // Multiple variables (Phase 33-7)
+    },
+    JoinIrTargetDesc {
+        func_name: "IfMergeTest.simple_false/0",
+        kind: JoinIrBridgeKind::Exec,
+        default_enabled: true, // Multiple variables (Phase 33-7)
+    },
+    // Selfhost/Production functions (Phase 33-4 explicit approvals)
+    JoinIrTargetDesc {
+        func_name: "JsonShapeToMap._read_value_from_pair/1",
+        kind: JoinIrBridgeKind::Exec,
+        default_enabled: true, // Stage-1 実用関数
+    },
+    JoinIrTargetDesc {
+        func_name: "Stage1JsonScannerBox.value_start_after_key_pos/2",
+        kind: JoinIrBridgeKind::Exec,
+        default_enabled: true, // Stage-B 実用関数
+    },
+];
+
+/// Phase 184: If lowering 対象関数の判定
+///
+/// JOINIR_IF_TARGETS テーブルから対象関数を検索し、
+/// default_enabled が true の関数のみを本線対象とする。
+///
+/// **用途**:
+/// - `is_if_mainline_target()`: Core ON 時の本線化判定
+/// - `should_try_joinir_mainline(func_name, is_loop=false)` 経由で使用
+pub fn is_if_lowered_function(name: &str) -> bool {
+    JOINIR_IF_TARGETS
+        .iter()
+        .any(|t| t.func_name == name && t.default_enabled)
+}