On 5/22/14 4:25 AM, Nick Coghlan wrote:

On 22 May 2014 12:00, "Ned Batchelder" <ned@nedbatchelder.com> wrote:
>
> I'm surprised at the amount of invention and mystery code people will propose to avoid having an off-switch for the code we already have.

It's not the off switch per se, it's the documentation and testing consequences. Better to figure out a way to let the code generator and analysis tools collaborate more effectively than to complicate the execution model further.

The problem with "letting them collaborate more effectively" is that we don't know how to do that. If we can come up with a way to do it, it will involve much more complex code than I am proposing.

As far as documentation, we have three possibilities for optimization level now. This will add a fourth. I don't see that as a burden.

On the testing front, if I were the developer of an optimizer, I would welcome a switch to disable it, as a way to test that optimizations don't change semantics. I understand that this is a different mode of execution. I guess we have different opinions about the tradeoff of risk and benefit of that new mode.

Cheers,
Nick.