refactor[venom]: add make_nop() helper function

vyper/venom/basicblock.py

@@ -318,6 +318,12 @@ def get_outputs(self) -> list[IROperand]:
         """
         return [self.output] if self.output else []
 
+    def make_nop(self):
+        self.annotation = str(self) # Keep original instruction as annotation for debugging
+        self.opcode = "nop" 
+        self.output = None
+        self.operands = []        
+
     def flip(self):
         """
         Flip operands for commutative or comparator opcodes
@@ -601,9 +607,7 @@ def fix_phi_instructions(self):
                 inst.opcode = "store"
                 inst.operands = [inst.operands[1]]
             elif op_len == 0:
-                inst.opcode = "nop"
-                inst.output = None
-                inst.operands = []
+                inst.make_nop()
 
         if needs_sort:
             self.instructions.sort(key=lambda inst: inst.opcode != "phi")

vyper/venom/passes/sccp/sccp.py

@@ -300,8 +300,7 @@ def _replace_constants(self, inst: IRInstruction):
 
             if isinstance(lat, IRLiteral):
                 if lat.value > 0:
-                    inst.opcode = "nop"
-                    inst.operands = []
+                    inst.make_nop()
                 else:
                     raise StaticAssertionException(
                         f"assertion found to fail at compile time ({inst.error_msg}).",