Can't find gcc bugzilla

Can't find gcc bugzilla

[Tim Wesson]

I'm a bit out of touch, having not programmed for a few years.

I have found a simple bug in gcc 3.4.3, and don't know who to report it
to, or how many others have already reported it.

I tried reporting it to Red Hat (as it appears to have been modified by
them), but it appears that I need an account so as to be able to report
a bug!

As the program is short easy to test, and likely to reflect a bug in the
pre-modified code, I thought that it would cost little, and perhaps save
time to post the test program with this request for help reporting bugs.

Thanks in advance,

Tim Wesson.


- gcc_bug.c below

/* bug in shift-left.

> gcc gcc_bug.c -o gcc_bug ./gcc_bug
shift:  1               (1ll << shift): 2
shift:  2               (1ll << shift): 4
shift:  3               (1ll << shift): 8
shift:  4               (1ll << shift): 16
shift:  5               (1ll << shift): 32
shift:  6               (1ll << shift): 64
shift:  7               (1ll << shift): 128
shift:  8               (1ll << shift): 256
shift:  9               (1ll << shift): 512
shift:  10              (1ll << shift): 1024
shift:  11              (1ll << shift): 2048
shift:  12              (1ll << shift): 4096
shift:  13              (1ll << shift): 8192
shift:  14              (1ll << shift): 16384
shift:  15              (1ll << shift): 32768
shift:  16              (1ll << shift): 65536
shift:  17              (1ll << shift): 131072
shift:  18              (1ll << shift): 262144
shift:  19              (1ll << shift): 524288
shift:  20              (1ll << shift): 1048576
shift:  21              (1ll << shift): 2097152
shift:  22              (1ll << shift): 4194304
shift:  23              (1ll << shift): 8388608
shift:  24              (1ll << shift): 16777216
shift:  25              (1ll << shift): 33554432
shift:  26              (1ll << shift): 67108864
shift:  27              (1ll << shift): 134217728
shift:  28              (1ll << shift): 268435456
shift:  29              (1ll << shift): 536870912
shift:  30              (1ll << shift): 1073741824
shift:  31              (1ll << shift): 2147483648
shift:  32              (1ll << shift): 4294967296
shift:  33              (1ll << shift): 8589934592
shift:  34              (1ll << shift): 17179869184
shift:  35              (1ll << shift): 34359738368
shift:  36              (1ll << shift): 68719476736
shift:  37              (1ll << shift): 137438953472
shift:  38              (1ll << shift): 274877906944
shift:  39              (1ll << shift): 549755813888
shift:  40              (1ll << shift): 1099511627776
shift:  41              (1ll << shift): 2199023255552
shift:  42              (1ll << shift): 4398046511104
shift:  43              (1ll << shift): 8796093022208
shift:  44              (1ll << shift): 17592186044416
shift:  45              (1ll << shift): 35184372088832
shift:  46              (1ll << shift): 70368744177664
shift:  47              (1ll << shift): 140737488355328
shift:  48              (1ll << shift): 281474976710656
shift:  49              (1ll << shift): 562949953421312
shift:  50              (1ll << shift): 1125899906842624
shift:  51              (1ll << shift): 2251799813685248
shift:  52              (1ll << shift): 4503599627370496
shift:  53              (1ll << shift): 9007199254740992
shift:  54              (1ll << shift): 18014398509481984
shift:  55              (1ll << shift): 36028797018963968
shift:  56              (1ll << shift): 72057594037927936
shift:  57              (1ll << shift): 144115188075855872
shift:  58              (1ll << shift): 288230376151711744
shift:  59              (1ll << shift): 576460752303423488
shift:  60              (1ll << shift): 1152921504606846976
shift:  61              (1ll << shift): 2305843009213693952
shift:  62              (1ll << shift): 4611686018427387904
shift:  63              (1ll << shift): -9223372036854775808
shift:  64              (1ll << shift): 1
shift:  65              (1ll << shift): 2
shift:  66              (1ll << shift): 4
[...]
> gcc --version
gcc (GCC) 3.4.3 20050227 (Red Hat 3.4.3-22.fc3)
[...]
> uname -a
Linux localhost.localdomain 2.6.11-1.14_FC3 #1 Thu Apr 7 19:23:49 EDT
2005 i686 athlon i386 GNU/Linux
*/

#include <stdio.h>

int main (void) {
  int shift;

  for (shift = 1;
       0ll != (1ll << shift); /* bug in gcc */
       shift++)
fprintf (stderr, "shift:\t%d\t\t"
	 "(1ll << shift):\t%lld\n",
	 shift, (1ll << shift));

  return (0); /* never get here */
}

Re: Can't find gcc bugzilla

[Eljay Love-Jensen]

Hi Tim,

What is the bug?

In C and C++, it is undefined what happens when you shift a data type equal-to-or-greater-than the number of bits of that data type.

Sincerely,
--Eljay