[PATCH 1/2] PR77822

[Segher Boessenkool]

On Fri, Nov 18, 2016 at 01:09:24PM +0100, Dominik Vogt wrote:
> How about this:
> 
> --
> /* A convenience macro to determine whether a SIZE lies inclusively
>    within [1, UPPER], POS lies inclusively within between
>    [0, UPPER - 1] and the sum lies inclusively within [1, UPPER].
>    UPPER must be >= 1.  */
> #define SIZE_POS_IN_RANGE(SIZE, POS, UPPER) \
>   (IN_RANGE ((POS), 0, (unsigned HOST_WIDE_INT) (UPPER) - 1) \
>    && IN_RANGE ((SIZE), 1, (unsigned HOST_WIDE_INT) (UPPER) \
>                            - (unsigned HOST_WIDE_INT)(POS)))
                                                       ^ missing space here

> IN_RANGE(POS...) makes sure that POS is a non-negative number
> smaller than UPPER, so (UPPER) - (POS) does not wrap.  Or is there
> some case that the new macro does not handle?

I think it works fine.

With a name like UPPER, you may want to have SIZE_POS_IN_RANGE work like
IN_RANGE, i.e. UPPER is inclusive then.  Dunno.


Segher