d7805e5974
Extended PatternPipelineContext and CarrierUpdateInfo for Pattern 3 AST-based generalization. Changes: 1. PatternPipelineContext: - Added loop_condition: Option<ASTNode> - Added loop_body: Option<Vec<ASTNode>> - Added loop_update_summary: Option<LoopUpdateSummary> - Updated build_pattern_context() for Pattern 3 2. CarrierUpdateInfo: - Added then_expr: Option<ASTNode> - Added else_expr: Option<ASTNode> - Updated analyze_loop_updates() with None defaults Status: Phase 213-2 Steps 2-2 & 2-3 complete Next: Create Pattern3IfAnalyzer to extract if statement and populate update summary
377 lines
13 KiB
Rust
377 lines
13 KiB
Rust
//! Phase 33: If/Else の Select 命令への lowering
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//!
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//! 最小の if/else（副作用なし、単純な値選択）を JoinInst::Select に変換する。
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//!
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//! ## 責務分離（Phase 33-9.1）
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//!
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//! **IfSelectLowerer の責務**:
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//! - 単純 if/else（副作用なし、単一変数）を Select 命令に変換する
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//!
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//! **非責務**:
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//! - Loop の PHI には触らない（Loop lowering の責務）
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use crate::mir::join_ir::JoinInst;
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use crate::mir::{BasicBlockId, MirFunction, MirInstruction, ValueId};
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// Phase 63-2: Type hint inference from MIR
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// Phase 61-1: If-in-loop context support
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use super::if_phi_context::IfPhiContext;
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pub struct IfSelectLowerer {
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debug_level: u8,
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// Phase 61-1: If-in-loop context (None = Pure If)
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#[allow(dead_code)]
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context: Option<IfPhiContext>,
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}
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/// If/Else パターンの分類
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#[derive(Debug, Clone, Copy)]
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enum IfPatternType {
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/// Simple pattern: if cond { return 1 } else { return 2 }
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Simple,
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/// Local pattern: if cond { x = a } else { x = b }; return x
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Local,
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}
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/// 検出された If/Else パターン情報
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#[derive(Debug, Clone)]
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struct IfPattern {
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pattern_type: IfPatternType,
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cond: ValueId,
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then_val: ValueId,
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else_val: ValueId,
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dst: Option<ValueId>,
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}
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/// Branch 命令の情報
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#[derive(Debug, Clone)]
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struct IfBranch {
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cond: ValueId,
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then_block: BasicBlockId,
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else_block: BasicBlockId,
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}
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impl IfSelectLowerer {
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pub fn new(debug_level: u8) -> Self {
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Self {
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debug_level,
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context: None, // Phase 61-1: デフォルトは Pure If
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}
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}
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/// Phase 33-8: debug-level backward compat wrapper
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#[allow(dead_code)]
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pub fn with_debug(debug: bool) -> Self {
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Self {
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debug_level: if debug { 1 } else { 0 },
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context: None, // Phase 61-1: デフォルトは Pure If
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}
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}
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/// Phase 61-1: If-in-loop 用コンストラクタ
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///
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/// # Arguments
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///
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/// * `debug_level` - デバッグログレベル (0-3)
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/// * `context` - If-in-loop コンテキスト（carrier_names 情報を含む）
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///
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/// # Example
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///
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/// ```ignore
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/// let context = IfPhiContext::for_loop_body(carrier_names);
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/// let lowerer = IfSelectLowerer::with_context(debug_level, context);
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/// ```
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pub fn with_context(debug_level: u8, context: IfPhiContext) -> Self {
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Self {
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debug_level,
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context: Some(context),
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}
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}
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/// if/else が Select に lowering できるかチェック
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pub fn can_lower_to_select(&self, func: &MirFunction, if_block_id: BasicBlockId) -> bool {
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self.find_if_pattern(func, if_block_id).is_some()
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}
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/// if/else を Select に変換
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pub fn lower_if_to_select(
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&self,
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func: &MirFunction,
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if_block_id: BasicBlockId,
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) -> Option<JoinInst> {
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let pattern = self.find_if_pattern(func, if_block_id)?;
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// Phase 33-8: Level 1 - Basic lowering info
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if self.debug_level >= 1 {
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eprintln!(
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"[IfSelectLowerer] ✅ lowering {:?} pattern to Select",
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pattern.pattern_type
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);
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}
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// Phase 33-8: Level 3 - Full pattern details
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if self.debug_level >= 3 {
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eprintln!("[IfSelectLowerer] cond: {:?}", pattern.cond);
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eprintln!("[IfSelectLowerer] then_val: {:?}", pattern.then_val);
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eprintln!("[IfSelectLowerer] else_val: {:?}", pattern.else_val);
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eprintln!("[IfSelectLowerer] dst: {:?}", pattern.dst);
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}
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// Select 命令を生成
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let dst = pattern.dst.unwrap_or(pattern.then_val);
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// Phase 63-2: MIR の Const 命令から型ヒントを推論
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let type_hint = infer_type_from_mir_pattern(func, pattern.then_val)
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.or_else(|| infer_type_from_mir_pattern(func, pattern.else_val));
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Some(JoinInst::Select {
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dst,
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cond: pattern.cond,
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then_val: pattern.then_val,
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else_val: pattern.else_val,
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type_hint, // Phase 63-2: Const 命令から推論した型（Integer/Bool/String など）
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})
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}
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/// MIR 関数から if/else パターンを探す
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fn find_if_pattern(&self, func: &MirFunction, block_id: BasicBlockId) -> Option<IfPattern> {
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// 1. Block が Branch 命令で終わっているか確認
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let block = func.blocks.get(&block_id)?;
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let branch = match block.terminator.as_ref()? {
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MirInstruction::Branch {
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condition,
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then_bb,
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else_bb,
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} => IfBranch {
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cond: *condition,
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then_block: *then_bb,
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else_block: *else_bb,
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},
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_ => return None,
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};
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// 2. then/else ブロックの構造を確認
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let then_block = func.blocks.get(&branch.then_block)?;
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let else_block = func.blocks.get(&branch.else_block)?;
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// Phase 33-10: PHI早期チェック（パターンマッチング前）
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// JoinIRは「PHI生成器」であり「PHI変換器」ではない
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// then/elseがJumpで終わる場合、merge blockにPHI命令があるか早期確認
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if let Some(merge_block_id) =
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self.get_merge_block_if_jump_pattern(&branch, then_block, else_block)
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{
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let merge_block = func.blocks.get(&merge_block_id)?;
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if merge_block
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.instructions
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.iter()
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.any(|inst| matches!(inst, MirInstruction::Phi { .. }))
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{
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if self.debug_level >= 2 {
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eprintln!("[IfSelectLowerer] ⏭️ PHI already exists in merge block, skipping");
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}
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return None;
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}
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}
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// 3. simple パターンのチェック
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if let Some(pattern) = self.try_match_simple_pattern(&branch, then_block, else_block) {
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// Phase 33-8: Level 2 - Pattern matching details
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if self.debug_level >= 2 {
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eprintln!("[IfSelectLowerer] ✅ matched simple pattern");
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}
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return Some(pattern);
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}
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// 4. local パターンのチェック
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if let Some(pattern) = self.try_match_local_pattern(func, &branch, then_block, else_block) {
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// Phase 33-8: Level 2 - Pattern matching details
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if self.debug_level >= 2 {
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eprintln!("[IfSelectLowerer] ✅ matched local pattern");
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}
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return Some(pattern);
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}
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// Phase 33-8: Level 2 - Pattern matching details
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if self.debug_level >= 2 {
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eprintln!("[IfSelectLowerer] ❌ no pattern matched");
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}
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None
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}
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/// simple パターン: if cond { return 1 } else { return 2 }
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///
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/// Phase 33-9.2: 実用MIR対応 - 副作用なし命令（Const/Copy）を許容
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/// - 旧: Return のみ（instructions empty）
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/// - 新: Const/Copy → Return を許容（実MIRパターン）
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fn try_match_simple_pattern(
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&self,
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branch: &IfBranch,
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then_block: &crate::mir::BasicBlock,
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else_block: &crate::mir::BasicBlock,
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) -> Option<IfPattern> {
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// then ブロックが Return だけか確認
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let then_val = match then_block.terminator.as_ref()? {
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MirInstruction::Return { value: Some(v) } => *v,
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_ => return None,
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};
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// else ブロックが Return だけか確認
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let else_val = match else_block.terminator.as_ref()? {
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MirInstruction::Return { value: Some(v) } => *v,
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_ => return None,
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};
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// Phase 33-9.2: 副作用なし命令（Const/Copy）のみを許容
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// - ユニットテスト（empty）も通過（空配列 → all() = true）
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// - 実用MIR（const + ret）も通過
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if !self.is_side_effect_free(&then_block.instructions)
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|| !self.is_side_effect_free(&else_block.instructions)
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{
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return None;
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}
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Some(IfPattern {
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pattern_type: IfPatternType::Simple,
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cond: branch.cond,
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then_val,
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else_val,
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dst: None,
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})
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}
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/// Phase 33-9.2: 副作用なし命令判定ヘルパー
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///
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/// Const/Copy のみを許容（分岐・call・書き込み等は除外）
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fn is_side_effect_free(&self, instructions: &[MirInstruction]) -> bool {
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instructions.iter().all(|inst| {
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matches!(
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inst,
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MirInstruction::Const { .. } | MirInstruction::Copy { .. }
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)
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})
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}
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/// Phase 33-10: Jump pattern 検出ヘルパー
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///
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/// then/else 両方が Jump で終わり、同じ merge block に飛んでいる場合、
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/// その merge block IDを返す
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fn get_merge_block_if_jump_pattern(
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&self,
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_branch: &IfBranch,
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then_block: &crate::mir::BasicBlock,
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else_block: &crate::mir::BasicBlock,
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) -> Option<BasicBlockId> {
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// then が Jump で終わるか確認
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let then_target = match then_block.terminator.as_ref()? {
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MirInstruction::Jump { target } => *target,
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_ => return None,
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};
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// else が Jump で終わるか確認
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let else_target = match else_block.terminator.as_ref()? {
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MirInstruction::Jump { target } => *target,
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_ => return None,
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};
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// 両方が同じ merge block に飛んでいるか確認
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if then_target == else_target {
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Some(then_target)
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} else {
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None
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}
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}
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/// local パターン: if cond { x = a } else { x = b }; return x
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///
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/// Phase 33-10: 実用MIR対応 - Const命令を許容
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/// - 旧: Copy命令のみ（ユニットテスト想定）
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/// - 新: Const/Copy命令を許容（実MIR対応、Simple patternと同じ修正）
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fn try_match_local_pattern(
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&self,
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func: &MirFunction,
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branch: &IfBranch,
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then_block: &crate::mir::BasicBlock,
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else_block: &crate::mir::BasicBlock,
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) -> Option<IfPattern> {
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// Phase 33-10: 副作用なし命令のみを許容
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if !self.is_side_effect_free(&then_block.instructions) {
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return None;
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}
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// then ブロックの最後の値を取得
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// Phase 33-10: Const命令も許容（実MIR対応）
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let (dst_then, val_then) = if then_block.instructions.len() == 1 {
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match &then_block.instructions[0] {
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MirInstruction::Copy { dst, src } => (*dst, *src),
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MirInstruction::Const { dst, .. } => (*dst, *dst), // Constの場合、dst自身が値
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_ => return None,
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}
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} else {
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return None;
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};
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// then ブロックが Jump で終わるか確認
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let merge_block_id = match then_block.terminator.as_ref()? {
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MirInstruction::Jump { target } => *target,
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_ => return None,
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};
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// Phase 33-10: else ブロックも副作用なし命令のみを許容
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if !self.is_side_effect_free(&else_block.instructions) {
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return None;
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}
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// else ブロックの最後の値を取得
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let (dst_else, val_else) = if else_block.instructions.len() == 1 {
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match &else_block.instructions[0] {
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MirInstruction::Copy { dst, src } => (*dst, *src),
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MirInstruction::Const { dst, .. } => (*dst, *dst), // Constの場合、dst自身が値
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_ => return None,
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}
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} else {
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return None;
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};
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// 代入先が同じ変数か確認
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if dst_then != dst_else {
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return None;
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}
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// else ブロックも同じ merge ブロックに Jump するか確認
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let else_merge = match else_block.terminator.as_ref()? {
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MirInstruction::Jump { target } => *target,
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_ => return None,
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};
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if merge_block_id != else_merge {
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return None;
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}
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// merge ブロックが「return dst」だけか確認
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let merge_block = func.blocks.get(&merge_block_id)?;
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// Phase 33-10: PHIチェックは find_if_pattern() で早期実行済み
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match merge_block.terminator.as_ref()? {
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MirInstruction::Return { value: Some(v) } if *v == dst_then => {
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// OK
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}
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_ => return None,
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}
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if !merge_block.instructions.is_empty() {
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return None;
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}
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Some(IfPattern {
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pattern_type: IfPatternType::Local,
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cond: branch.cond,
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then_val: val_then,
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else_val: val_else,
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dst: Some(dst_then),
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})
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}
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}
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// Phase 185: infer_type_from_mir_pattern() moved to common.rs
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use super::common::infer_type_from_mir_pattern;
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