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

[Joe Buck]

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.