|
| 1 | +/* { dg-do run } */ |
| 2 | + |
| 3 | +/* Testcase distilled from glibc's nss_parse_service_list in nss/nsswitch.c |
| 4 | + It can't be distilled further. Fails with `-O2' for i[3456]86. */ |
| 5 | + |
| 6 | +/* this simulates a bounded-pointer type. */ |
| 7 | +struct ucharp { unsigned char *v, *l, *h; }; |
| 8 | + |
| 9 | +/* this simulates bounded-pointer check prior to pointer dereference. */ |
| 10 | +#define AREF(var, idx) ((((((((var).v+(idx)) < (var).l) \ |
| 11 | + || (((var).v+(idx)+1) > (var).h))) \ |
| 12 | + && (__builtin_trap (), 0)), \ |
| 13 | + (var).v)[(idx)]) |
| 14 | + |
| 15 | +struct list |
| 16 | +{ |
| 17 | + struct list *next; |
| 18 | +}; |
| 19 | + |
| 20 | +struct list * |
| 21 | +alloc_list (void) |
| 22 | +{ |
| 23 | + static struct list l; |
| 24 | + return &l; |
| 25 | +} |
| 26 | + |
| 27 | +int one = 1; |
| 28 | + |
| 29 | +void |
| 30 | +foo (struct ucharp cp, struct ucharp lp, struct list **nextp) |
| 31 | +{ |
| 32 | + while (1) |
| 33 | + { |
| 34 | + struct list *list; |
| 35 | + while (AREF (lp, 0) && AREF (cp, AREF (lp, 0))) |
| 36 | + ++lp.v; |
| 37 | + list = alloc_list (); |
| 38 | + while (AREF (cp, AREF (lp, 0))) |
| 39 | + ++lp.v; |
| 40 | + if (AREF (lp, 0) == one) |
| 41 | + do |
| 42 | + ++lp.v; |
| 43 | + while (AREF (lp, 0) && AREF (cp, AREF (lp, 0))); |
| 44 | + /* The above AREF (cp, ...) fails because the pseudo created to |
| 45 | + hold cp.v holds garbage, having never been set. |
| 46 | + The easiest way to see the problem is to compile wiht `-O2 -da' |
| 47 | + then look at *.09.loop. Search for something like this: |
| 48 | +
|
| 49 | + Hoisted regno 183 r/o from (mem/s:SI (reg:SI 16 argp) 10) |
| 50 | + Replaced reg 91, deleting init_insn (213). |
| 51 | +
|
| 52 | + Now, look for the use of reg 91, which has no set. */ |
| 53 | + |
| 54 | + *nextp = list; |
| 55 | + nextp = &list->next; |
| 56 | + if (!*lp.v) |
| 57 | + break; |
| 58 | + } |
| 59 | +} |
| 60 | + |
| 61 | +extern void exit (int); |
| 62 | + |
| 63 | +int |
| 64 | +main (void) |
| 65 | +{ |
| 66 | + static unsigned char cp0[] = "\0\0\0\0"; |
| 67 | + struct ucharp cp = { cp0, cp0, cp0 + sizeof (cp0) }; |
| 68 | + |
| 69 | + static unsigned char lp0[] = "\1\1\0\0"; |
| 70 | + struct ucharp lp = { lp0, lp0, lp0 + sizeof (lp0) }; |
| 71 | + |
| 72 | + struct list list; |
| 73 | + struct list *nextp = &list; |
| 74 | + |
| 75 | + foo (cp, lp, &nextp); |
| 76 | + |
| 77 | + exit (0); |
| 78 | +} |
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