[Bug c/46460] New: shifting producing incorrect result

[keefeg at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46460

           Summary: shifting producing incorrect result
           Product: gcc
           Version: 4.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: keefeg@gmail.com


% cat bug.c
#include <stdio.h>

int main(void) {
  unsigned int ShouldBeZero;
  int cnt = 32;

  ShouldBeZero = 0xFFFFFFFF >> cnt;

  printf("Should print 0 here: %u\n", ShouldBeZero);

  return 0;
}

% cc -o bug bug.c
% ./bug
Should print 0 here: 4294967295

% cc -o bug -O3 bug.c
% ./bug
Should print 0 here: 0

% gcc -v
Using built-in specs.
Target: amd64-undermydesk-freebsd
Configured with: FreeBSD/amd64 system compiler
Thread model: posix
gcc version 4.2.1 20070719  [FreeBSD]

% sysctl -a | grep 'hw\.model'
hw.model: AMD Phenom(tm) II X4 955 Processor