[PATCH] Remove seemingly dead InstCombine compare code

[Matt Arsenault]

On 08/12/2013 04:16 PM, Eli Friedman wrote:
> On Mon, Aug 5, 2013 at 3:11 PM, Matt Arsenault
> <Matthew.Arsenault at amd.com> wrote:
>>    Add missing check lines
>>
>>    test1_noinbounds shows the current behavior. Why wouldn't it be valid?
> Because you don't know how X was computed, it could be anything.  For
> example, it could be "@some_other_zero_int - @G16", an arbitrarily
> large number which is not 9, but the address would point at a 0.
>
> If that's the current behavior, it's a bug.
>
> -Eli
>
I still don't really understand. If you're subtracting the addresses of 
2 different objects, that's undefined. If you're accessing somewhere 
outside of the global, that is also undefined, so how is there another 
legal way to access the same item?