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Re: [LLVMdev] Handling of pointer difference in llvm-gcc and clang
So it seems like we agreed that this is a problem that should be fixed.
Shall I create a bug report suggesting for it?
Am Friday, 12. August 2011, 09:32:11 schrieb 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.