[Bug c++/81642] New: -Wtype-limits should not trigger for defined numbers

[seikusaro at web dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81642

            Bug ID: 81642
           Summary: -Wtype-limits should not trigger for defined numbers
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: seikusaro at web dot de
  Target Milestone: ---

Hi,
My Problem is similar to https://gcc.gnu.org/bugzilla/show_bug.cgi?id=51712

bool foo(const unsigned port)
{
  if(port<NUM_IFC) return false;
  return true;
}

Our Make will parse a file for every project to get the specific values that
are defines like NUM_IFC.
So if a project has NUM_IFC equal 0 we will get a warning:
warning: comparison of unsigned expression < 0 is always false [-Wtype-limits]
But with some projects the number is greater then 0 on those we obviously get
no warning.
I can understand why the compiler gives out a warning and I can suppress it
with a cast to signed.
Yet do you see any way to make gcc see it as intended since it comes from
define.
Best Regards