feat: フェーズM.2完了 - JSON v0 Bridge層PHI統一でno_phi完全撤廃

- strip_phi_functions()削除: 40行の複雑なPHI→edge-copy後処理撤廃
- JSON v0 Bridge 8箇所のno_phi分岐完全削除:
  - try_catch.rs: 3箇所統一
  - ternary.rs, peek.rs, expr.rs, loop_.rs: 各1-2箇所統一
- config::env::mir_no_phi()大幅簡略化: 40行→8行、phi-legacy依存除去
- 未使用コード削除: PHI_ON_GATED_WARNED static、mir_no_phiフィールド
- 未使用import削除: HashSet、collect_phi_incoming_if_reachable

効果: フェーズM+M.2で推定500行超削減、MIR層PHI完全統一達成
Phase 15セルフホスティング80k→20k行圧縮の主要基盤完成

🤖 Generated with [Claude Code](https://claude.ai/code)

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

CLAUDE.md

@@ -276,15 +276,16 @@ NYASH_DISABLE_PLUGINS=1 ./target/release/nyash program.nyash
 NYASH_LLVM_USE_HARNESS=1 ./target/release/nyash program.nyash
 ```
 
-## 📝 Update (2025-09-22) ⚡ フェーズM実装大幅進展！PHI一本化によるコード大削減達成
+## 📝 Update (2025-09-23) 🚀 フェーズM+M.2完全達成！PHI統一革命完了
-- ✅ **MirBuilder no_phi_mode完全撤廃！** phi.rs、exprs_peek.rs全分岐をPHI命令一本化
+- ✅ **フェーズM.2完全達成！** JSON v0 Bridge層クリーンアップ完了でPHI完全統一実現
-- ✅ **LoopBuilder no_phi_mode完全撤廃！** 3箇所のedge copy分岐をPHI命令一本化  
+- ✅ **8箇所のno_phi分岐完全削除！** try_catch(3)、ternary(1)、peek(1)、loop_(2)、expr(1)
-- ✅ **edge_copy関連コード削除！** insert_edge_copy()メソッド含む数十行削減
+- ✅ **strip_phi_functions()削除！** 40行の複雑なPHI→edge-copy後処理撤廃
-- 🔧 **ビルド成功維持！** フェーズS+フェーズM修正でもエラーなしを確認
+- ✅ **config::env::mir_no_phi()大幅簡略化！** 40行→8行、phi-legacy依存完全除去
-- ⏳ **JSON v0 Bridge保留中**: Phase 15重要コンポーネントのため慎重対応予定
+- ✅ **未使用コード完全削除！** PHI_ON_GATED_WARNED static、mir_no_phiフィールド等
-- 🎯 **次の一歩**: collect_prints動作確認→JSON v0 Bridge対応→フェーズM完了
+- 🔧 **安定性完全確認！** cargo check成功、基本・複雑PHIテスト両方正常動作
-- 📊 **戦略文書更新**: break-control-flow-strategy.mdの段階的根治計画に沿って実行
+- 📊 **圧縮効果絶大！** フェーズM+M.2で推定500行超削減達成
-- 🚀 **効果**: 数百行削減によりPhase 15の80k→20k圧縮目標に大きく貢献
+- 🎯 **Phase 15準備完了**: MIR層PHI統一により80k→20k行圧縮の主要基盤完成
+- 🚀 **次段階**: collect_prints動作確認→JSON v0 Bridge最終統合→Phase 15完遂
 
 ## 📝 Update (2025-09-22) 🎯 Phase 15 JITアーカイブ完了＆デバッグ大進展！
 - ✅ **JIT/Craneliftアーカイブ完了！** Phase 15集中開発のため全JIT機能を安全にアーカイブ

src/config/env.rs

@@ -36,7 +36,7 @@ use once_cell::sync::OnceCell;
 use std::sync::RwLock;
 
 static GLOBAL_ENV: OnceCell<RwLock<NyashEnv>> = OnceCell::new();
-static PHI_ON_GATED_WARNED: OnceCell<()> = OnceCell::new();
+// フェーズM.2: PHI_ON_GATED_WARNED削除（phi-legacy簡略化により不要）
 
 pub fn current() -> NyashEnv {
     if let Some(lock) = GLOBAL_ENV.get() {
@@ -109,47 +109,13 @@ pub fn await_max_ms() -> u64 {
 }
 
 // ---- MIR PHI / PHI-less (edge-copy) mode ----
-/// Enable MIR PHI non-generation. Bridge/Builder emit edge copies instead of PHI.
+/// Enable MIR PHI non-generation for Bridge compatibility mode only.
-/// Default: PHI-ON when the build supports it (feature `phi-legacy`), otherwise fall back to PHI-OFF.
+/// フェーズM.2: MirBuilder/LoopBuilderでPHI統一済み、Bridge層の互換性制御のみ
+/// Default: PHI-ON (Phase 15 direction), override with NYASH_MIR_NO_PHI=1
 pub fn mir_no_phi() -> bool {
-    match std::env::var("NYASH_MIR_NO_PHI").ok() {
+    match std::env::var("NYASH_MIR_NO_PHI").ok().as_deref() {
-        Some(v) => {
+        Some("1") | Some("true") | Some("on") => true,
-            let lv = v.to_ascii_lowercase();
+        _ => false, // フェーズM.2: デフォルトPHI-ON統一
-            let requested_no_phi = !(lv == "0" || lv == "false" || lv == "off");
-            if requested_no_phi {
-                return true;
-            }
-            // PHI-on requested explicitly
-            #[cfg(feature = "phi-legacy")]
-            {
-                return false;
-            }
-            #[cfg(not(feature = "phi-legacy"))]
-            {
-                if PHI_ON_GATED_WARNED.set(()).is_ok() {
-                    eprintln!(
-                        "[nyash] PHI-on requested but disabled in this build (missing 'phi-legacy' feature). Falling back to PHI-off."
-                    );
-                }
-                return true;
-            }
-        }
-        None => {
-            // Default preference: PHI-ON if available
-            #[cfg(feature = "phi-legacy")]
-            {
-                return false;
-            }
-            #[cfg(not(feature = "phi-legacy"))]
-            {
-                if PHI_ON_GATED_WARNED.set(()).is_ok() {
-                    eprintln!(
-                        "[nyash] Default PHI-on requested but build lacks 'phi-legacy' feature; falling back to PHI-off."
-                    );
-                }
-                return true;
-            }
-        }
     }
 }
 

src/mir/loop_builder.rs

@@ -7,13 +7,12 @@
 
 use super::{BasicBlockId, ConstValue, MirInstruction, ValueId};
 use crate::ast::ASTNode;
-use std::collections::{HashMap, HashSet};
+use std::collections::HashMap;
 
 // Phase 15 段階的根治戦略：制御フローユーティリティ
 use super::utils::{
     is_current_block_terminated,
     capture_actual_predecessor_and_jump,
-    collect_phi_incoming_if_reachable,
 };
 
 /// 不完全なPhi nodeの情報

src/runner/json_v0_bridge/lowering.rs

@@ -26,7 +26,7 @@ pub(super) struct LoopContext {
 #[derive(Clone)]
 pub(super) struct BridgeEnv {
     pub(super) throw_enabled: bool,
-    pub(super) mir_no_phi: bool,
+    // フェーズM.2: mir_no_phiフィールド削除（PHI統一で不要）
     pub(super) allow_me_dummy: bool,
     pub(super) me_class: String,
     pub(super) try_result_mode: bool,
@@ -35,13 +35,13 @@ pub(super) struct BridgeEnv {
 impl BridgeEnv {
     pub(super) fn load() -> Self {
         let trm = crate::config::env::try_result_mode();
-        let no_phi = crate::config::env::mir_no_phi();
+        // フェーズM.2: no_phi変数削除
         if crate::config::env::cli_verbose() {
-            eprintln!("[Bridge] load: try_result_mode={} mir_no_phi={}", trm, no_phi);
+            eprintln!("[Bridge] load: try_result_mode={}", trm);
         }
         Self {
             throw_enabled: std::env::var("NYASH_BRIDGE_THROW_ENABLE").ok().as_deref() == Some("1"),
-            mir_no_phi: no_phi,
+            // フェーズM.2: mir_no_phiフィールド削除
             allow_me_dummy: std::env::var("NYASH_BRIDGE_ME_DUMMY").ok().as_deref() == Some("1"),
             me_class: std::env::var("NYASH_BRIDGE_ME_CLASS").unwrap_or_else(|_| "Main".to_string()),
             try_result_mode: trm,
@@ -61,45 +61,7 @@ fn jump_with_pred(f: &mut MirFunction, cur_bb: BasicBlockId, target: BasicBlockI
 
 /// Strip Phi instructions by inserting edge copies on each predecessor.
 /// This normalizes MIR to PHI-off form for downstream harnesses that synthesize PHIs.
-fn strip_phi_functions(f: &mut MirFunction) {
+// フェーズM.2: strip_phi_functions()削除 - PHI統一により不要
-    // Collect block ids to avoid borrow issues while mutating
-    let block_ids: Vec<BasicBlockId> = f.blocks.keys().copied().collect();
-    for bbid in block_ids {
-        // Snapshot phi instructions at the head
-        let mut phi_entries: Vec<(ValueId, Vec<(BasicBlockId, ValueId)>)> = Vec::new();
-        if let Some(bb) = f.blocks.get(&bbid) {
-            for inst in &bb.instructions {
-                if let MirInstruction::Phi { dst, inputs } = inst {
-                    phi_entries.push((*dst, inputs.clone()));
-                } else {
-                    // PHIs must be at the beginning; once we see non-Phi, stop
-                    break;
-                }
-            }
-        }
-        if phi_entries.is_empty() {
-            continue;
-        }
-        // Insert copies on predecessors
-        for (dst, inputs) in &phi_entries {
-            for (pred, val) in inputs {
-                if let Some(pbb) = f.blocks.get_mut(pred) {
-                    pbb.add_instruction(MirInstruction::Copy { dst: *dst, src: *val });
-                }
-            }
-        }
-        // Remove Phi instructions from the merge block
-        if let Some(bb) = f.blocks.get_mut(&bbid) {
-            let non_phi: Vec<MirInstruction> = bb
-                .instructions
-                .iter()
-                .cloned()
-                .skip_while(|inst| matches!(inst, MirInstruction::Phi { .. }))
-                .collect();
-            bb.instructions = non_phi;
-        }
-    }
-}
 
 fn lower_break_stmt(f: &mut MirFunction, cur_bb: BasicBlockId, exit_bb: BasicBlockId) {
     jump_with_pred(f, cur_bb, exit_bb);
@@ -256,10 +218,7 @@ pub(super) fn lower_program(prog: ProgramV0) -> Result<MirModule, String> {
         }
     }
     f.signature.return_type = MirType::Unknown;
-    // PHI-off normalization for Bridge output
+    // フェーズM.2: PHI後処理削除 - MirBuilder/LoopBuilderでPHI統一済み
-    if env.mir_no_phi {
-        strip_phi_functions(&mut f);
-    }
     module.add_function(f);
     Ok(module)
 }

src/runner/json_v0_bridge/lowering/expr.rs

@@ -255,14 +255,8 @@ pub(super) fn lower_expr_with_scope<S: VarScope>(
                 }
             }
             let out = f.next_value_id();
-            if env.mir_no_phi {
+            // フェーズM.2: PHI統一処理（no_phi分岐削除）
-                if let Some(bb) = f.get_block_mut(fall_bb) {
+            if let Some(bb) = f.get_block_mut(merge_bb) {
-                    bb.add_instruction(MirInstruction::Copy { dst: out, src: cdst });
-                }
-                if let Some(bb) = f.get_block_mut(rhs_end) {
-                    bb.add_instruction(MirInstruction::Copy { dst: out, src: rval });
-                }
-            } else if let Some(bb) = f.get_block_mut(merge_bb) {
                 let mut inputs: Vec<(BasicBlockId, ValueId)> = vec![(fall_bb, cdst)];
                 if rhs_end != fall_bb {
                     inputs.push((rhs_end, rval));

src/runner/json_v0_bridge/lowering/loop_.rs

@@ -21,18 +21,15 @@ pub(super) fn lower_loop_stmt(
             bb.add_instruction(MirInstruction::Jump { target: cond_bb });
         }
     }
-    let no_phi = env.mir_no_phi;
+    // フェーズM.2: no_phi変数削除
     let base_vars = vars.clone();
     let orig_names: Vec<String> = base_vars.keys().cloned().collect();
     let mut phi_map: HashMap<String, ValueId> = HashMap::new();
     for name in &orig_names {
         if let Some(&bval) = base_vars.get(name) {
             let dst = f.next_value_id();
-            if no_phi {
+            // フェーズM.2: PHI統一処理（no_phi分岐削除）
-                if let Some(bb) = f.get_block_mut(cur_bb) {
+            if let Some(bb) = f.get_block_mut(cond_bb) {
-                    bb.add_instruction(MirInstruction::Copy { dst, src: bval });
-                }
-            } else if let Some(bb) = f.get_block_mut(cond_bb) {
                 bb.insert_instruction_after_phis(MirInstruction::Phi {
                     dst,
                     inputs: vec![(cur_bb, bval)],
@@ -69,18 +66,8 @@ pub(super) fn lower_loop_stmt(
         Some(MirInstruction::Jump { target, .. }) if *target == cond_bb
     );
     if backedge_to_cond {
-        if no_phi {
+        // フェーズM.2: PHI統一処理（no_phi分岐削除）
-            for (name, &phi_dst) in &phi_map {
+        if let Some(bb) = f.get_block_mut(cond_bb) {
-                if let Some(&latch_val) = body_vars.get(name) {
-                    if let Some(bb) = f.get_block_mut(bend) {
-                        bb.add_instruction(MirInstruction::Copy {
-                            dst: phi_dst,
-                            src: latch_val,
-                        });
-                    }
-                }
-            }
-        } else if let Some(bb) = f.get_block_mut(cond_bb) {
             for (name, &phi_dst) in &phi_map {
                 if let Some(&latch_val) = body_vars.get(name) {
                     for inst in &mut bb.instructions {

src/runner/json_v0_bridge/lowering/peek.rs

@@ -69,13 +69,8 @@ pub(super) fn lower_peek_expr_with_scope<S: VarScope>(
 
     // Merge result
     let out = f.next_value_id();
-    if env.mir_no_phi {
+    // フェーズM.2: PHI統一処理（no_phi分岐削除）
-        for (pred, val) in phi_inputs {
+    if let Some(bb) = f.get_block_mut(merge_bb) {
-            if let Some(bb) = f.get_block_mut(pred) {
-                bb.add_instruction(MirInstruction::Copy { dst: out, src: val });
-            }
-        }
-    } else if let Some(bb) = f.get_block_mut(merge_bb) {
         let mut inputs = phi_inputs;
         inputs.sort_by_key(|(bbid, _)| bbid.0);
         bb.insert_instruction_after_phis(MirInstruction::Phi { dst: out, inputs });

src/runner/json_v0_bridge/lowering/ternary.rs

@@ -44,14 +44,8 @@ pub(super) fn lower_ternary_expr_with_scope<S: VarScope>(
         }
     }
     let out = f.next_value_id();
-    if env.mir_no_phi {
+    // フェーズM.2: PHI統一処理（no_phi分岐削除）
-        if let Some(bb) = f.get_block_mut(tend) {
+    if let Some(bb) = f.get_block_mut(merge_bb) {
-            bb.add_instruction(MirInstruction::Copy { dst: out, src: tval });
-        }
-        if let Some(bb) = f.get_block_mut(eend) {
-            bb.add_instruction(MirInstruction::Copy { dst: out, src: eval });
-        }
-    } else if let Some(bb) = f.get_block_mut(merge_bb) {
         let mut inputs = vec![(tend, tval), (eend, eval)];
         inputs.sort_by_key(|(bbid, _)| bbid.0);
         bb.insert_instruction_after_phis(MirInstruction::Phi { dst: out, inputs });

src/runner/json_v0_bridge/lowering/try_catch.rs

@@ -70,7 +70,8 @@ pub(super) fn lower_try_stmt(
             let catch_clause = &catches[0];
             let mut catch_vars = base_vars.clone();
             if let Some(param) = &catch_clause.param {
-                if !env.mir_no_phi && !incoming_exc.is_empty() {
+                // フェーズM.2: PHI統一処理（no_phi条件削除）
+                if !incoming_exc.is_empty() {
                     let phi_dst = f.next_value_id();
                     if let Some(bb) = f.get_block_mut(catch_bb) {
                         let mut inputs = incoming_exc.clone();
@@ -281,16 +282,8 @@ pub(super) fn lower_try_stmt(
             phi_entries.push((dst, inputs));
             merged_vars.insert(name.clone(), dst);
         }
-        if env.mir_no_phi {
+        // フェーズM.2: PHI統一処理（no_phi分岐削除）
-            // Emit edge copies on predecessors instead of Phi at merge
+        if let Some(bb) = f.get_block_mut(finally_block) {
-            for (dst, inputs) in phi_entries {
-                for (pred, val) in inputs {
-                    if let Some(pbb) = f.get_block_mut(pred) {
-                        pbb.add_instruction(MirInstruction::Copy { dst, src: val });
-                    }
-                }
-            }
-        } else if let Some(bb) = f.get_block_mut(finally_block) {
             for (dst, inputs) in phi_entries {
                 bb.insert_instruction_after_phis(MirInstruction::Phi { dst, inputs });
             }
@@ -344,15 +337,8 @@ pub(super) fn lower_try_stmt(
             phi_entries.push((dst, inputs));
             merged_vars.insert(name.clone(), dst);
         }
-        if env.mir_no_phi {
+        // フェーズM.2: PHI統一処理（no_phi分岐削除）
-            for (dst, inputs) in phi_entries {
+        if let Some(bb) = f.get_block_mut(exit_bb) {
-                for (pred, val) in inputs {
-                    if let Some(pbb) = f.get_block_mut(pred) {
-                        pbb.add_instruction(MirInstruction::Copy { dst, src: val });
-                    }
-                }
-            }
-        } else if let Some(bb) = f.get_block_mut(exit_bb) {
             for (dst, inputs) in phi_entries {
                 bb.insert_instruction_after_phis(MirInstruction::Phi { dst, inputs });
             }