On Wed, 15 Jul 2015 03:29 am, Marko Rauhamaa wrote: > Chris Angelico <ros...@gmail.com>: > >> On Tue, Jul 14, 2015 at 11:38 PM, Marko Rauhamaa <ma...@pacujo.net> >> wrote: >>> No, tail call optimization doesn't change the behavior of the >>> program, for the worse anyway. >> >> It does, because you lose traceback records. That's pretty significant >> when you come to try to debug something. > > Doesn't count.
Says you. > Optimization can do weird things to code and make > debugging challenging. That's why you usually tell the compiler not to > optimize the debug builds. Here's a real scenario for you to chew on: testing. Test suites should be considered an application where the developer is the end user, and the point of the application is to verify that the code passes tests, and if they don't, present the user (i.e. the developer) with sufficient information to debug the problem (i.e. full stack traces). So how do you test your optimized code? If you turn optimizations on globally, you're testing something which may or may not have the same behaviour as the code you wrote. Compiler bugs exist, so it is more important than ever to ensure that the post-optimization code passes the test suite. But if it fails, you no longer get the stack traces you need to debug the problem. But if you turn optimizations off globally, you're not testing the optimized code any longer. -- Steven -- https://mail.python.org/mailman/listinfo/python-list
