[PATCH] d3dx9: Don't check for negative enum value.

Jacek Caban jacek at codeweavers.com
Tue Mar 24 09:50:31 CDT 2020

On 24.03.2020 15:39, Matteo Bruni wrote:
> On Tue, Mar 24, 2020 at 3:29 PM Jacek Caban <jacek at codeweavers.com> wrote:
>> On 24.03.2020 14:59, Henri Verbeet wrote:
>>> On Tue, 24 Mar 2020 at 17:45, Matteo Bruni <matteo.mystral at gmail.com> wrote:
>>>> I assume replacing "op < 0" with an explicit "op < SCT_VSFLOAT"
>>>> doesn't avoid the warning. Does replacing the if with an assert do the
>>>> trick, by any chance?
>>> It's perhaps a little subtle, but if you compare "op" against
>>> "ARRAY_SIZE(const_tbl)" (which is what you really care about here
>>> anyway, right?) instead of SCT_PSINT, you can drop the check against
>>> 0, regardless of whether the enum ends up being a signed or unsigned
>>> type.
>> Strictly speaking, if enum would be signed the check wouldn't catch some
>> invalid values, but I don't think that's worrying about. If we want it
>> fully strict, we could change argument type from enum to unsigned int.
>> Thanks,
>> Jacek
> I think sizeof() (and thus ARRAY_SIZE()) always returns an unsigned
> integer, op is promoted to unsigned if necessary and the comparison is
> guaranteed to be unsigned.

Sure, but theoretically if underlying type of enum is signed char 
(actually, signed part is not important), then it will be truncated 
before being promoted.


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