Change CompoundInstruction semantics

kernel/modelverse_jit/tree_ir.py

@@ -455,13 +455,13 @@ class CompoundInstruction(Instruction):
 
     def has_result(self):
         """Tells if this instruction has a result."""
-        return self.second.has_result()
+        return self.second.has_result() or self.first.has_result()
 
     def simplify(self):
         """Applies basic simplification to this instruction and its children."""
-
         simple_fst, simple_snd = self.first.simplify(), self.second.simplify()
-        if not simple_fst.has_definition():
+        if not simple_fst.has_definition() and (
+                not simple_fst.has_result() or simple_snd.has_result()):
             return simple_snd
         elif (not simple_snd.has_definition()) and (not simple_snd.has_result()):
             return simple_fst
@@ -470,8 +470,15 @@ class CompoundInstruction(Instruction):
 
     def generate_python_def(self, code_generator):
         """Generates Python code for this instruction."""
-        self.first.generate_python_def(code_generator)
-        code_generator.append_move_definition(self, self.second)
+        if self.second.has_result():
+            self.first.generate_python_def(code_generator)
+            code_generator.append_move_definition(self, self.second)
+        elif self.first.has_result():
+            code_generator.append_move_definition(self, self.first)
+            self.second.generate_python_def(code_generator)
+        else:
+            self.first.generate_python_def(code_generator)
+            self.second.generate_python_def(code_generator)
 
 class LiteralInstruction(Instruction):
     """Represents an integer, floating-point, string or Boolean literal."""