Re: Schedule for GNU make 3.81

[Eli Zaretskii]

> Date: Wed, 16 Feb 2005 01:45:41 -0500
> From: address@hidden
> 
>     http://make.paulandlesley.org/make-3.81beta2.tar.bz2
>     http://make.paulandlesley.org/make-3.81beta2.tar.gz

Here's an annoyance with this beta version when I build it with DJGPP
and GCC 3.3.3 or 3.4.3:

  gcc -I. -I. -I. -I./glob -DLIBDIR=\"c:/djgpp/lib\" 
-DINCLUDEDIR=\"c:/djgpp/include\" -DLOCALEDIR=\"/share/locale\" -DHAVE_CONFIG_H 
-O2 -g -c file.c
  file.c: In function `file_timestamp_cons':
  file.c:554: warning: comparison is always true due to limited range of data 
type

The macro-expanded version of the function file_timestamp_cons is
below.  The expression that triggers the warning seems to be the first
line of the `if' clause, viz.:

  if (! (s <= (((((((((~ (unsigned long long) 0 - (! ((unsigned long long) -1 < 
0) ? (unsigned long long) 0 : ~ (unsigned long long) 0 << (sizeof (unsigned 
long long) * 8 - 1)))) - (2 + 1)) >> (0 ? 30 : 0)) << (0 ? 30 : 0)) + (2 + 1) + 
(0 ? 1000000000 : 1) - 1)) - (2 + 1)) >> (0 ? 30 : 0))

I might be wrong, but I think that the offending comparison is this:

  (unsigned long long) -1 < 0

which comes from this line in make.h:

  #define INTEGER_TYPE_SIGNED(t) ((t) -1 < 0)

I tried a few tricks to avoid the warning, but was unable to shut it
up.  Can someone see what's wrong and how to fix that?

----------------------------------------------------------------------
unsigned long long
file_timestamp_cons (const char *fname, time_t s, int ns)
{
  int offset = (2 + 1) + (0 ? ns : 0);
  unsigned long long product = (unsigned long long) s << (0 ? 30 : 0);
  unsigned long long ts = product + offset;

  if (! (s <= (((((((((~ (unsigned long long) 0 - (! ((unsigned long long) -1 < 
0) ? (unsigned long long) 0 : ~ (unsigned long long) 0 << (sizeof (unsigned 
long long) * 8 - 1)))) - (2 + 1)) >> (0 ? 30 : 0)) << (0 ? 30 : 0)) + (2 + 1) + 
(0 ? 1000000000 : 1) - 1)) - (2 + 1)) >> (0 ? 30 : 0))
         && product <= ts && ts <= ((((((~ (unsigned long long) 0 - (! 
((unsigned long long) -1 < 0) ? (unsigned long long) 0 : ~ (unsigned long long) 
0 << (sizeof (unsigned long long) * 8 - 1)))) - (2 + 1)) >> (0 ? 30 : 0)) << (0 
? 30 : 0)) + (2 + 1) + (0 ? 1000000000 : 1) - 1)))
    {
      char buf[(((sizeof (unsigned long long) * 8 - 1 - 24) * 302 / 1000) + 1 + 
1 + 4 + 25) + 1];
      ts = s <= 2 ? (2 + 1) : ((((((~ (unsigned long long) 0 - (! ((unsigned 
long long) -1 < 0) ? (unsigned long long) 0 : ~ (unsigned long long) 0 << 
(sizeof (unsigned long long) * 8 - 1)))) - (2 + 1)) >> (0 ? 30 : 0)) << (0 ? 30 
: 0)) + (2 + 1) + (0 ? 1000000000 : 1) - 1);
      file_timestamp_sprintf (buf, ts);
      error (((struct floc *)0), ((const char *) ("%s: Timestamp out of range; 
substituting %s")),
             fname ? fname : ((const char *) ("Current time")), buf);
    }

  return ts;
}