The following code causes gcc to emit a warning that does not seem to have a diagnostic name, which makes it hard (impossible?) to disable:

=========================================
#include <stddef.h>
#include <stdbool.h>

bool foo(unsigned long not_a_pointer) {
  return not_a_pointer == NULL;
}
=========================================
<source>: In function 'foo':
<source>:5:24: warning: comparison between pointer and integer
    5 |   return not_a_pointer == NULL;
      |                        ^~
=========================================
Godbolt link: https://gcc.godbolt.org/z/chcxYevvf

I don't think anyone would argue that this is "good" (portable, defined, etc) C code; it is vendor code that I'm stuck with. Additionally, on the architecture I'm targeting, the implementation does the right thing: the unsigned long is pointer-sized, and is compared against the NULL literal 0, which is used in this context as a sentinel value. The code should use the literal 0 instead of NULL, but it does not.

I have 3 suggestions, if they're helpful:

1. If this warning can be disabled, update the diagnostic message to include the name as a hint on how to disable it.

2. If this warning can not be disabled, consider giving it a formal diagnostic name and making it controllable via the standard methods (-Wno-, pragma, etc)

3. If this is truly heinous / unsafe enough, promote it to an error.

Thanks for all of your efforts on gcc!

Best,
Charles