diff --git a/src/mir/loop_builder.rs b/src/mir/loop_builder.rs
index c3a62f35..116fba39 100644
--- a/src/mir/loop_builder.rs
+++ b/src/mir/loop_builder.rs
@@ -51,34 +51,6 @@ impl<'a> LoopBuilder<'a> {
     /// Find the source value of a Copy instruction in a given block
     /// If `dst` is defined by a Copy instruction `dst = copy src`, return Some(src)
     /// Otherwise return None
-    fn find_copy_source(&self, block_id: BasicBlockId, dst: ValueId) -> Option<ValueId> {
-        let func = self.parent_builder.current_function.as_ref()?;
-        let block = func.blocks.get(&block_id)?;
-
-        let trace = std::env::var("NYASH_LOOP_TRACE").ok().as_deref() == Some("1");
-        if trace {
-            eprintln!("[loop/copy-trace] searching for dst={:?} in block={:?}, {} instructions",
-                dst, block_id, block.instructions.len());
-        }
-
-        for (idx, inst) in block.instructions.iter().enumerate() {
-            if let MirInstruction::Copy { dst: inst_dst, src } = inst {
-                if trace {
-                    eprintln!("[loop/copy-trace]   inst#{}: %{} = copy %{}", idx, inst_dst.0, src.0);
-                }
-                if *inst_dst == dst {
-                    if trace {
-                        eprintln!("[loop/copy-trace]   FOUND! dst={:?} src={:?}", dst, src);
-                    }
-                    return Some(*src);
-                }
-            }
-        }
-        if trace {
-            eprintln!("[loop/copy-trace]   NOT FOUND for dst={:?}", dst);
-        }
-        None
-    }
 
     // =============================================================
     // Control Helpers — break/continue/jumps/unreachable handling
@@ -415,57 +387,6 @@ impl<'a> LoopBuilder<'a> {
     /// - ループキャリア（ループ本体で再代入される変数）と pinned 変数のみを PHI 対象とする。
     /// - ループ不変のローカル（text_len / pattern_len など）は preheader 値をそのまま使い、
     ///   不要な PHI を張らないことで SSA 破綻（同一 ValueId の二重定義）を防ぐ。
-    fn prepare_loop_variables(
-        &mut self,
-        header_id: BasicBlockId,
-        preheader_id: BasicBlockId,
-        pre_vars_snapshot: &std::collections::HashMap<String, ValueId>,
-        assigned_vars: &[String],
-    ) -> Result<Vec<crate::mir::phi_core::loop_phi::IncompletePhi>, String> {
-        use std::sync::atomic::{AtomicUsize, Ordering};
-        static CALL_COUNT: AtomicUsize = AtomicUsize::new(0);
-        let count = CALL_COUNT.fetch_add(1, Ordering::SeqCst);
-
-        // Use the variable map captured at preheader (before switching to header),
-        // but filter to:
-        // - ループキャリア（assigned_vars に含まれる変数）
-        // - pinned 変数（__pin$*）: 受信箱など、ループをまたいで値を運ぶ必要があるもの
-        let mut current_vars = std::collections::HashMap::new();
-        for (name, &val) in pre_vars_snapshot.iter() {
-            if name.starts_with("__pin$") {
-                current_vars.insert(name.clone(), val);
-                continue;
-            }
-            if assigned_vars.iter().any(|v| v == name) {
-                current_vars.insert(name.clone(), val);
-            }
-        }
-        // Debug: print current_vars before prepare (guarded by env)
-        let dbg = std::env::var("NYASH_BUILDER_DEBUG").ok().as_deref() == Some("1");
-        if dbg {
-            eprintln!("[DEBUG] prepare_loop_variables call #{}", count);
-            eprintln!("[DEBUG]   current_vars = {:?}", current_vars);
-            eprintln!(
-                "[DEBUG]   preheader_id = {:?}, header_id = {:?}",
-                preheader_id, header_id
-            );
-        }
-        crate::mir::phi_core::loop_phi::save_block_snapshot(
-            &mut self.block_var_maps,
-            preheader_id,
-            &current_vars,
-        );
-        let incs = crate::mir::phi_core::loop_phi::prepare_loop_variables_with(
-            self,
-            header_id,
-            preheader_id,
-            &current_vars,
-        )?;
-        // Defer variable rebinding to PHI IDs until after the loop condition is emitted.
-        // Store incomplete PHIs for later sealing and for rebinding after branch emission.
-        self.incomplete_phis.insert(header_id, incs.clone());
-        Ok(incs)
-    }
 
     /// ブロックをシールし、不完全なPhi nodeを完成させる