[Bug c/48717] New: likely integer wrong code bug

[regehr at cs dot utah.edu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48717

           Summary: likely integer wrong code bug
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: regehr@cs.utah.edu


[regehr@gamow tmp012]$ current-gcc -O1 small.c -o small
[regehr@gamow tmp012]$ ./small
65535
[regehr@gamow tmp012]$ current-gcc -O2 small.c -o small
[regehr@gamow tmp012]$ ./small
-1
[regehr@gamow tmp012]$ current-gcc -v

Using built-in specs.
COLLECT_GCC=current-gcc
COLLECT_LTO_WRAPPER=/uusoc/exports/scratch/regehr/z/compiler-install/gcc-r172845-install/bin/../libexec/gcc/x86_64-unknown-linux-gnu/4.7.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../configure --with-libelf=/usr/local --enable-lto
--prefix=/home/regehr/z/compiler-install/gcc-r172845-install
--program-prefix=r172845- --enable-languages=c,c++
Thread model: posix
gcc version 4.7.0 20110421 (experimental) (GCC) 

[regehr@gamow tmp012]$ cat small.c


unsigned short safe_52 (unsigned short ui1, unsigned short ui2)
{
  return ui1 + ui2;
}

extern int printf (const char *, ...);

int g_7 = 1;

int g_8;

void func_1 (void)
{
  g_7 = safe_52 (~g_8, g_8);
}

int main (void)
{
  func_1 ();
  printf ("%d\n", g_7);
  return 0;
}