[llvm-dev] Unsigned int displaying as negative

Ryan Taylor via llvm-dev llvm-dev at lists.llvm.org
Thu Feb 16 10:15:04 PST 2017


  The issue is saturation is treated differently for signed than it is for


On Thu, Feb 16, 2017 at 9:49 AM, Tim Northover <t.p.northover at gmail.com>

> On 15 February 2017 at 17:02, Ryan Taylor <ryta1203 at gmail.com> wrote:
> > Tim, yes, I am on a very unique architecture, just about every
> instruction
> > has a signed and unsigned operation (ie, adds, addu, subs, subu, etc...)
> and
> > we handle signed and unsigned somewhat differently.
> What's special about them? Flag setting? Trapping? Not a 2s-complement
> representation? Something else entirely?
> Roughly, to provide decent advice I think we need to know what goes
> wrong if you map everything to unsigned operations. Both C and LLVM IR
> view that as an acceptable choice so fixing the issue is likely to be
> intricate.
> Cheers.
> Tim.
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