[Bug c/30916] New: Wrong ‘float’ rather than ‘double’ due to prototype warning

["hermantenbrugge at home dot nl" <gcc-bugzilla at gcc dot gnu dot org>]

The following code:

void func (float a);
void
func (float a)
{
}

int
main (void)
{
  func (3.0f);
  return 0;
}

Compiled with: gcc -Wconversion bug.c
produces:
bug.c: In function ?main?:
bug.c:10: warning: passing argument 1 of ?func? as ?float? rather than ?double?
due to prototype

I was not expecting this.

When looking at the code in c-typeck.c at line 2473.
I see:
                      /* Warn if any argument is passed as `float',
                         since without a prototype it would be `double'.  */
                      if (formal_prec == TYPE_PRECISION (float_type_node)
                          && type != dfloat32_type_node)

Should the dfloat32_type_node be changed into float_type_node?
When I change this no warning is produced anymore.


-- 
           Summary: Wrong ?float? rather than ?double? due to prototype
                    warning
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: hermantenbrugge at home dot nl
 GCC build triplet: x86_64-unknown-linux-gnu
  GCC host triplet: x86_64-unknown-linux-gnu
GCC target triplet: x86_64-unknown-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30916