On Thu, Oct 24, 2013 at 7:15 PM, Lawrence Crowl <Lawrence_at_[hidden]> wrote:
> On 10/24/13, John Regehr <regehr_at_[hidden]> wrote:
>> There's no way Unisys's compiler implements non-two's-complement if they
>> run any substantial amount of C/C++ from the wild.
>
> Those machines have historically been programmed in Algol. I really have
> no idea how much C code they run.

As of 2011, Unisys appeared to be using LLVM per:

http://lists.cs.uiuc.edu/pipermail/llvmdev/2011-August/042185.html

While that's not definitive proof that they are using C or C++, it is
at least a datapoint worth considering. Perhaps it would make sense
to reach out to someone at Unisys to find out definitively.

~Aaron