http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53001

             Bug #: 53001
           Summary: -Wfloat-conversion should be available to warn about
                    floating point errors
    Classification: Unclassified
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: c
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: jjcogliati...@yahoo.com


This is a request to add a new warning that warns on the subset of -Wconversion
warnings that involve floating point numbers.  For example, with
-Wfloat-conversion this would cause a warning:

int main(int argc, char ** argv) {
  int i = 3.14;
  return i;
}

I think this could mostly be done by modifying gcc/c-family/c-common.c
unsafe_conversion_p to add the ability to only warn on conversions where
REAL_TYPE or REAL_CST are involved.  

The reason -Wconversion is not sufficient is that using it can cause hundreds
of warnings, almost all of which are integer size warnings (many of which are
in libraries (such as libMesh)).  I would like to be able to enable something
like -Wfloat-conversion that would catch errors involving floating point number
conversions, while ignoring the integer size conversions.

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