diff --git a/src/bloqade/qasm2/passes/noise.py b/src/bloqade/qasm2/passes/noise.py
index b91c1e51..477bd62a 100644
--- a/src/bloqade/qasm2/passes/noise.py
+++ b/src/bloqade/qasm2/passes/noise.py
@@ -1,7 +1,7 @@
 from dataclasses import field, dataclass
 
 from kirin import ir
-from kirin.passes import Pass
+from kirin.passes import Pass, HintConst
 from kirin.rewrite import (
     Walk,
     Chain,
@@ -10,11 +10,10 @@
     DeadCodeElimination,
     CommonSubexpressionElimination,
 )
-from kirin.rewrite.abc import RewriteResult
 
 from bloqade.noise import native
 from bloqade.analysis import address
-from bloqade.qasm2.rewrite.heuristic_noise import NoiseRewriteRule
+from bloqade.qasm2.rewrite.heuristic_noise import InsertGetQubit, NoiseRewriteRule
 
 
 @dataclass
@@ -38,16 +37,17 @@ def __post_init__(self):
         self.address_analysis = address.AddressAnalysis(self.dialects)
 
     def unsafe_run(self, mt: ir.Method):
-        result = RewriteResult()
-
-        frame, res = self.address_analysis.run_analysis(mt, no_raise=False)
+        result = Walk(InsertGetQubit()).rewrite(mt.code)
+        HintConst(self.dialects).unsafe_run(mt)
+        frame, _ = self.address_analysis.run_analysis(mt, no_raise=self.no_raise)
         result = (
             Walk(
                 NoiseRewriteRule(
                     address_analysis=frame.entries,
                     noise_model=self.noise_model,
                     gate_noise_params=self.gate_noise_params,
-                )
+                ),
+                reverse=True,
             )
             .rewrite(mt.code)
             .join(result)
diff --git a/src/bloqade/qasm2/rewrite/heuristic_noise.py b/src/bloqade/qasm2/rewrite/heuristic_noise.py
index 7556079f..edb06fed 100644
--- a/src/bloqade/qasm2/rewrite/heuristic_noise.py
+++ b/src/bloqade/qasm2/rewrite/heuristic_noise.py
@@ -10,6 +10,34 @@
 from bloqade.qasm2.dialects import uop, core, glob, parallel
 
 
+class InsertGetQubit(rewrite_abc.RewriteRule):
+
+    def rewrite_Statement(self, node: ir.Statement) -> rewrite_abc.RewriteResult:
+        if (
+            not isinstance(node, core.QRegNew)
+            or not isinstance(n_qubits_stmt := node.n_qubits.owner, py.Constant)
+            or not isinstance(n_qubits := n_qubits_stmt.value.unwrap(), int)
+            or (block := node.parent_block) is None
+        ):
+            return rewrite_abc.RewriteResult()
+
+        n_qubits_stmt.detach()
+        node.detach()
+        if block.first_stmt is None:
+            block.stmts.append(node)
+        else:
+            node.insert_before(block.first_stmt)
+            n_qubits_stmt.insert_before(block.first_stmt)
+
+        for idx_val in range(n_qubits):
+            idx = py.constant.Constant(value=idx_val)
+            qubit = core.QRegGet(node.result, idx=idx.result)
+            qubit.insert_after(node)
+            idx.insert_after(node)
+
+        return rewrite_abc.RewriteResult(has_done_something=True)
+
+
 @dataclass
 class NoiseRewriteRule(rewrite_abc.RewriteRule):
     """
@@ -24,12 +52,18 @@ class NoiseRewriteRule(rewrite_abc.RewriteRule):
     noise_model: native.MoveNoiseModelABC = field(
         default_factory=native.TwoRowZoneModel
     )
-    qubit_ssa_value: Dict[int, ir.SSAValue] = field(default_factory=dict, init=False)
+
+    def __post_init__(self):
+        self.qubit_ssa_value: Dict[int, ir.SSAValue] = {}
+        for ssa_value, addr in self.address_analysis.items():
+            if (
+                isinstance(addr, address.AddressQubit)
+                and ssa_value not in self.qubit_ssa_value
+            ):
+                self.qubit_ssa_value[addr.data] = ssa_value
 
     def rewrite_Statement(self, node: ir.Statement) -> rewrite_abc.RewriteResult:
-        if isinstance(node, core.QRegNew):
-            return self.rewrite_qreg_new(node)
-        elif isinstance(node, uop.SingleQubitGate):
+        if isinstance(node, uop.SingleQubitGate):
             return self.rewrite_single_qubit_gate(node)
         elif isinstance(node, uop.CZ):
             return self.rewrite_cz_gate(node)
@@ -42,24 +76,6 @@ def rewrite_Statement(self, node: ir.Statement) -> rewrite_abc.RewriteResult:
         else:
             return rewrite_abc.RewriteResult()
 
-    def rewrite_qreg_new(self, node: core.QRegNew):
-
-        addr = self.address_analysis[node.result]
-        if not isinstance(addr, address.AddressReg):
-            return rewrite_abc.RewriteResult()
-
-        has_done_something = False
-        for idx_val, qid in enumerate(addr.data):
-            if qid not in self.qubit_ssa_value:
-                has_done_something = True
-                idx = py.constant.Constant(value=idx_val)
-                qubit = core.QRegGet(node.result, idx=idx.result)
-                self.qubit_ssa_value[qid] = qubit.result
-                qubit.insert_after(node)
-                idx.insert_after(node)
-
-        return rewrite_abc.RewriteResult(has_done_something=has_done_something)
-
     def insert_single_qubit_noise(
         self,
         node: ir.Statement,
diff --git a/src/bloqade/qasm2/rewrite/uop_to_parallel.py b/src/bloqade/qasm2/rewrite/uop_to_parallel.py
index d7d1ee7e..3f546121 100644
--- a/src/bloqade/qasm2/rewrite/uop_to_parallel.py
+++ b/src/bloqade/qasm2/rewrite/uop_to_parallel.py
@@ -154,7 +154,7 @@ def __call__(self, node: ir.Statement) -> RewriteResult:
             self.group_has_merged[group_number] = result.has_done_something
             return result
 
-        if self.group_has_merged[group_number]:
+        if self.group_has_merged.setdefault(group_number, False):
             node.delete()
 
         return RewriteResult(has_done_something=self.group_has_merged[group_number])