[cfe-dev] Feature request: C intrinsics for overflow detection

[Richard Smith]

On Fri, May 9, 2014 at 10:55 AM, Reid Kleckner <rnk at google.com> wrote:

> They are exposed:
>
> http://clang.llvm.org/docs/LanguageExtensions.html#checked-arithmetic-builtins
>
> ... but that's not indexed by Google.  Maybe this is the problem?
> http://clang.llvm.org/robots.txt:
> User-agent: *
> Disallow:
>

That's an 'allow everything' robots.txt. The results are there; try
searching for: "__builtin_uadd_overflow" clang


> On Fri, May 9, 2014 at 10:27 AM, Andy Lutomirski <luto at amacapital.net>wrote:
>
>> LLVM has the llvm.*.with.overflow.* intrinsics.  Can these be exposed
>> to C code?  I imagine this would be straightforward, aside from the
>> obligatory bikeshedding about exactly what the interface should be.
>>
>> This would eliminate a lot of nasty hacks used to check for overflow,
>> especially for multiplication overflow.  I currently write this stuff
>> in inline x86 assembler -- ugh!  And maybe gcc would go along if clang
>> paved the way :)
>>
>> --Andy
>> _______________________________________________
>> cfe-dev mailing list
>> cfe-dev at cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
>>
>
>
> _______________________________________________
> cfe-dev mailing list
> cfe-dev at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-dev/attachments/20140509/d7b4b5cf/attachment.html>