Suppress (verbose) may-be-used-uninitialized errors.

Cython/Compiler/ModuleNode.py

@@ -702,6 +702,7 @@ class ModuleNode(Nodes.Node, Nodes.BlockNode):
         PyrexTypes.c_int_type.create_from_py_utility_code(env)
 
         code.put(Nodes.branch_prediction_macros)
+        code.putln('static CYTHON_INLINE void __Pyx_pretend_to_initialize(void* ptr) {}')
         code.putln('')
         code.putln('static PyObject *%s;' % env.module_cname)
         code.putln('static PyObject *%s;' % env.module_dict_cname)

Cython/Compiler/Nodes.py

@@ -1938,6 +1938,8 @@ class FuncDefNode(StatNode, BlockNode):
                 val = self.return_type.default_value
                 if val:
                     code.putln("%s = %s;" % (Naming.retval_cname, val))
+                elif not self.return_type.is_void:
+                    code.putln("__Pyx_pretend_to_initialize(&%s);" % Naming.retval_cname)
         # ----- Error cleanup
         if code.error_label in code.labels_used:
             if not self.body.is_terminator:
@@ -1992,6 +1994,8 @@ class FuncDefNode(StatNode, BlockNode):
                 err_val = default_retval
             if err_val is not None:
                 code.putln("%s = %s;" % (Naming.retval_cname, err_val))
+            elif not self.return_type.is_void:
+                code.putln("__Pyx_pretend_to_initialize(&%s);" % Naming.retval_cname)
 
             if is_getbuffer_slot:
                 self.getbuffer_error_cleanup(code)