Re: C++ PATCH to fix missing warning (PR c++/70194)

[Martin Sebor <msebor@gmail.com>]

>> While I would find the warning less misleading if it simply said
>> in all three cases: "the address of 'x' will always evaluate as
>> ‘true’" I think it would be even more accurate if it said
>> "the address of 'x' may be assumed to evaluate to ‘true’"  That
>> avoids making claims about whether or not it actually is null,
>> doesn't talk about the NULL macro when one isn't used in the
>> code, and by saying "may assume" it allows for both making
>> the assumption as well as not making one.
>
> That sounds good except that talking about 'true' is wrong when there is
> an explicit comparison to a null pointer constant.  I'd be fine with
> changing "NULL" to "null" or similar.

Sounds good.  I will use bug 47931 - missing -Waddress warning
for comparison with NULL, to take care of the outstanding cases
where a warning still isn't issued (in either C++ or C) and also
adjust the text of the warning.

Martin

PS It seems that just adding STRIP_NOPS (op) to Marek's patch
significantly increases the number of successfully diagnosed
cases.  (The small patch I attached to 47931 covers nearly all
the remaining cases I could think of.)