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Re: __int256
On Jul 13, 2012, at 12:33 AM, Richard Guenther wrote:
> On Fri, Jul 13, 2012 at 3:59 AM, Mike Stump <mikestump@comcast.net> wrote:
>> This patch adds __int256 to the front-ends.
>> We have another patch underway to do N-bit constant ints, where N is defined by the port. This patch is in the process of being reviewed now, and Kenny should be able to submit it shortly.
>
> How do you handle the fact that we cannot represent all constants of __int256
> or larger with an INTEGER_CST? I think this introduces latent wrong-code
> bugs almost everywhere in the compiler.
As I said, in Kenny's next patch, we add support for all constants of any size the port needs. I don't know if you've ever tried to use the compiler with OImode, but, what I can say is the bugs are not terribly latent at times and they are not hidden very well at all, today. The goal of course, is to improve that and make it work better. These issues that I know about existed, prior to my patch, and we are in the process of fixing them. Some have been fixed, others remain to be fixed. The issues I'm thinking about exist with or without my patch to the frontend to support __int256. Merely adding __int256 doesn't make any of the issues I'm aware of appear, and the issues I'm aware of don't appear with sizes less than 256.
I have put the patch through the C test suite, and it doesn't show any failures.
Do you have any examples of bugs that are _introduced_ by my patch? I'd be happy to fix any that arise.