[Bug c/38696] New: gcc.dg/torture/pr37868.c wrong code at -O2 and above for 4.3 and trunk / bit packing

[laurent at guerby dot net]

GCC 4.3.2-1 debian gnueabi and trunk at rev 142984 generate wrong code at -O2
and above for pr37868.c

gue...@gcc50:~$ /home/guerby/build-142984/gcc/xgcc
-B/home/guerby/build-142984/gcc/
/home/guerby/trunk/gcc/testsuite/gcc.dg/torture/pr37868.c   -O2 -lm   -o
./pr37868.exegue...@gcc50:~$ ./pr37868.exe 
Aborted

gue...@gcc50:~$ cat /home/guerby/trunk/gcc/testsuite/gcc.dg/torture/pr37868.c 
/* { dg-do run } */
/* { dg-options "-fno-strict-aliasing" } */
/* { dg-skip-if "unaligned access" { sparc*-*-* } "*" "" } */

extern void abort (void);

struct X {
  unsigned char pad : 4;
  unsigned int a : 32;
  unsigned int b : 24;
  unsigned int c : 6;
} __attribute__((packed));

int main (void)
{
  struct X x;
  unsigned int bad_bits;

  x.pad = -1;
  x.a = -1;
  x.b = -1;
  x.c = -1;

  bad_bits = ((unsigned int)-1) ^ *(1+(unsigned int *) &x);
  if (bad_bits != 0)
    abort ();
  return 0;
}


-- 
           Summary: gcc.dg/torture/pr37868.c wrong code at -O2 and above for
                    4.3 and trunk / bit packing
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: laurent at guerby dot net
 GCC build triplet: arm-linux-gnueabi
  GCC host triplet: arm-linux-gnueabi
GCC target triplet: arm-linux-gnueabi


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38696