[Bug target/20126] [3.3/3.4/4.0 Regression] Inlined memcmp makes one argument null on entry

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-02-21 22:15 -------
Reduced testcase (and shows that this is also a 3.3/3.4/4.0 Regression too):
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
typedef struct {
    struct _object *_ob_next;
    struct _object *_ob_prev;
    int ob_refcnt;
    struct _typeobject *ob_type;
    int ob_size;
    long ob_shash;
    int ob_sstate;
    char ob_sval[1];
} strobject;
static int
string_contains(strobject *a, strobject *el)
{
 const char *lhs, *rhs, *end;
 int size;

 size = (((el))->ob_size);
 rhs = (((el))->ob_sval);
 lhs = (((a))->ob_sval);

 if (size == 1)
  return memchr(lhs, *rhs, (((a))->ob_size)) != ((void *)0);

 end = lhs + ((((a))->ob_size) - size);
 while (lhs <= end) {
  const char *t = lhs+1;
  if (memcmp(lhs, rhs, size) == 0)
   return 1;
  lhs = t;
 }
 return 0;
}
int
main(void)
{
 char* s1 = "aa";
 char* s2 = "aa";
 strobject *obj1;
 strobject *obj2;
 obj1 = calloc(1, sizeof (*obj1) + 64);
 obj2 = calloc(1, sizeof (*obj2) + 64);
 obj1->ob_size = strlen(s1);
 obj2->ob_size = strlen(s2);
 memcpy(&obj1->ob_sval[0], s1, obj1->ob_size);
 memcpy(&obj2->ob_sval[0], s2, obj2->ob_size);
 printf("'%*s' in '%*s' = %d\n",
        obj2->ob_size, obj2->ob_sval,
        obj1->ob_size, obj1->ob_sval,
        string_contains(obj1, obj2));
 return 0;
}


-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
      Known to fail|                            |3.3.3 3.4.0 4.0.0
      Known to work|                            |3.2.3
   Last reconfirmed|0000-00-00 00:00:00         |2005-02-21 22:15:27
               date|                            |
            Summary|Inlined memcmp makes one    |[3.3/3.4/4.0 Regression]
                   |argument null on entry      |Inlined memcmp makes one
                   |                            |argument null on entry
   Target Milestone|---                         |3.4.4


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20126