Make a few common cases not use temporary for buffer acquisition

Cython/Compiler/ExprNodes.py

@@ -1227,15 +1227,21 @@ class NameNode(AtomicExprNode):
         # rhstmp is only used in case the rhs is a complicated expression leading to
         # the object, to avoid repeating the same C expression for every reference
         # to the rhs. It does NOT hold a reference.
+        pretty_rhs = isinstance(rhs, NameNode) or rhs.is_temp
+        if pretty_rhs:
+            rhstmp = rhs.result_as(self.ctype())
+        else:
             rhstmp = code.funcstate.allocate_temp(self.entry.type, manage_ref=False)
-        buffer_aux = self.entry.buffer_aux
-        bufstruct = buffer_aux.buffer_info_var.cname
             code.putln('%s = %s;' % (rhstmp, rhs.result_as(self.ctype())))
 
+        buffer_aux = self.entry.buffer_aux
+        bufstruct = buffer_aux.buffer_info_var.cname
         import Buffer
         Buffer.put_assign_to_buffer(self.result(), rhstmp, buffer_aux, self.entry.type,
                                     is_initialized=not self.lhs_of_first_assignment,
                                     pos=self.pos, code=code)
+        
+        if not pretty_rhs:
             code.putln("%s = 0;" % rhstmp)
             code.funcstate.release_temp(rhstmp)