[LLVMdev] Checked arithmetic

Chris Lattner sabre at nondot.org
Wed Mar 26 11:02:16 PDT 2008


On Wed, 26 Mar 2008, Jonathan S. Shapiro wrote:
> I want to background process this for a bit, but it would be helpful to
> discuss some approaches first.
>
> There would appear to be three approaches:
>
>  1. Introduce a CC register class into the IR. This seems to be a
>     fairly major overhaul.
>
>  2. Introduce a set of scalar and fp computation quasi-instructions
>     that accept the same arguments as their computational counterparts,
>     but produce *only* the condition code. For example:

Why not define an "add with overflow" intrinsic that returns its value and 
overflow bit as an i1?

-Chris

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