Function prototype with K&R definition and resulting call.

I'm noticing some behavior I don't understand. There is a function prototype in scope but the function definition is K&R style. My understanding is the actual call to the function should be non-varargs since the prototype is present. What I'm seeing is the call is being made as a varargs call. What is the correct behavior in this case?

This code was derived from a test in the gcc test suite. This happens when using clang with the -O0 option.

If the definition of the function is:
static void
attr_eq (name)
     char * name;
{...}

The call generated is:
call void (...)* bitcast (void (i8*)* @attr_eq to void (...)*)(i8* getelementptr inbounds ([5 x i8]* @arg0, i32 0, i32 0))

Here's the complete code:
extern void abort (void);

static char arg0[] = "arg0";

static void attr_eq (char *);

void attr_rtx (char *);
char *attr_string (char *);

static void
attr_eq (name)
     char * name;
/*
attr_eq (char * name)
*/
{
   attr_rtx (attr_string (name));
  
}

int main()
{
   attr_eq (arg0);
   exit (0);
}

If a prototype is visible, the fact that there's also a definition
shouldn't have any effect; sounds like a bug.

See also the discussion in http://llvm.org/bugs/show_bug.cgi?id=10713 .

-Eli