[LLVMdev] Handling of pointer difference in llvm-gcc and clang

[Richard Guenther]

On Thu, Aug 11, 2011 at 10:36 PM, Joe Buck <Joe.Buck@synopsys.com> wrote:
> On Thu, Aug 11, 2011 at 1:58 PM, Joseph S. Myers
> <joseph@codesourcery.com> wrote:
>>  -ftrapv and -fwrapv should have no effect on pointer subtraction.
>
> Gaby writes:
>
>> Yes!
>
> Wouldn't it suffice to convert the pointers to unsigned, do an unsigned subtraction, and then convert the result to signed? This would then guarantee that gcc uses two's complement semantics, independent of -ftrapv.

Of course, I think that is what is being proposed.

Richard.