add pop_top

Author: savannahostrowski

Tools/cases_generator/optimizer_generator.py

@@ -233,6 +233,18 @@ def replace_opcode_if_evaluates_pure(
             else:
                 emitter.emit(f"{outp.name} = sym_new_const(ctx, PyStackRef_AsPyObjectBorrow({outp.name}_stackref));\n")
 
+        if len(used_stack_inputs) == 1 and len(self.original_uop.stack.outputs) == 1:
+            outp = self.original_uop.stack.outputs[0]
+            if not outp.peek:
+                emitter.emit(f"""
+            if (sym_is_const(ctx, {used_stack_inputs[0].name})) {{
+                PyObject *result = sym_get_const(ctx, {used_stack_inputs[0].name});
+                if (_Py_IsImmortal(result)) {{
+                    // Replace with _POP_LOAD_CONST_INLINE_BORROW since we have one input and an immortal result
+                    REPLACE_OP(this_instr, _POP_LOAD_CONST_INLINE_BORROW, 0, (uintptr_t)result);
+                }}
+            }}""")
+
         if len(used_stack_inputs) == 2 and len(self.original_uop.stack.outputs) == 1:
                 outp = self.original_uop.stack.outputs[0]
                 if not outp.peek: