fixing bug in parallel with reverse order

Author: weinbe58

src/bloqade/qasm2/rewrite/uop_to_parallel.py

@@ -58,6 +58,10 @@ class SimpleMergePolicy(MergePolicyABC):
     group_has_merged: Dict[int, bool] = field(default_factory=dict)
     """Mapping from group number to whether the group has been merged"""
 
+    def __post_init__(self):
+        for group_number in range(len(self.merge_groups)):
+            self.group_has_merged[group_number] = False
+
     @staticmethod
     def same_id_checker(ssa1: ir.SSAValue, ssa2: ir.SSAValue):
         if ssa1 is ssa2:
@@ -154,7 +158,7 @@ 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])