[Bug middle-end/29695] New: [4.1/4.2/4.3 Regression] Folding breaks (a & 0x80) ? 0x80 : 0 for unsigned char or unsigned short a

[jakub at gcc dot gnu dot org]

extern void abort (void);

int
f1 (void)
{
  int a = 128;
  return (a & 0x80) ? 0x80 : 0;
}

int
f2 (void)
{
  unsigned char a = 128;
  return (a & 0x80) ? 0x80 : 0;
}

int
main (void)
{
  if (f1 () != 128)
    abort ();
  if (f2 () != 128)
    abort ();
  return 0;
}

f2 () is miscompiled with -O2 (on x86-64 and ppc at least), returns -128 rather
than 128.


-- 
           Summary: [4.1/4.2/4.3 Regression] Folding breaks (a & 0x80) ?
                    0x80 : 0 for unsigned char or unsigned short a
           Product: gcc
           Version: 4.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: jakub at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29695