gcc/testsuite/gcc.dg/tree-ssa/pr79376.c

   1 /* PR tree-optimization/79376 - wrong lower bound with %s and non-constant
   2    strings in -Wformat-overflow
   3    { dg-do compile }
   4    { dg-options "-O2 -fdump-tree-optimized" } */
   5
   6 #define CAT(s, n)   s ## n
   7 #define FAIL(line)  CAT (failure_on_line_, line)
   8
   9 /* Emit a call to a function named failure_on_line_NNN when EXPR is false.  */
  10 #define ASSERT(expr)                            \
  11   do {                                          \
  12     extern void FAIL (__LINE__)(void);          \
  13     if (!(expr)) FAIL (__LINE__)();             \
  14   } while (0)
  15
  16 #define KEEP(line)  CAT (keep_call_on_line_, line)
  17
  18 /* Emit a call to a function named keep_call_on_line_NNN when EXPR is true.
  19    Used to verify that the expression need not be the only one that holds.  */
  20 #define ASSERT_MAYBE(expr)                      \
  21   do {                                          \
  22     extern void KEEP (__LINE__)(void);          \
  23     if (expr) KEEP (__LINE__)();                \
  24   } while (0)
  25
  26 struct Arrays
  27 {
  28   char a1[1];
  29   char a2[2];
  30   char a3[3];
  31   char a4[4];
  32   char a5[5];
  33   char ax[];
  34 };
  35
  36 void test_arrays (int i, struct Arrays *a)
  37 {
  38   {
  39     const char *s = i < 0 ? a->a3 : a->a1;
  40
  41     int n = __builtin_snprintf (0, 0, "%-s", s);
  42
  43     /* Since it's undefined to pass an unterminated array to a %s
  44        directive it would be valid to assume that S above is not
  45        longer than sizeof (A->A3) but the optimization isn't done
  46        because the GIMPLE representation of the %s argument isn't
  47        suffficiently reliable not to confuse it for some other
  48        array.  The argument length is therefore assumed to be in
  49        the range [0, PTRDIFF_MAX - 2] and the sprintf result to be
  50        as big as INT_MAX and possibly even negative if the function
  51        were to fail due to a single directive resulting in more than
  52        the 4,095 byte maximum required to be supported.
  53        ASSERT (0 <= n && n < 3);
  54     */
  55
  56     ASSERT_MAYBE (0 == n);
  57     ASSERT_MAYBE (1 == n);
  58     ASSERT_MAYBE (2 == n);
  59   }
  60
  61   {
  62     const char *s = i < 0 ? a->a3 : a->a5;
  63
  64     int n = __builtin_snprintf (0, 0, "%-s", s);
  65
  66     /* ASSERT (0 <= n && n < 5); */
  67
  68     ASSERT_MAYBE (0 == n);
  69     ASSERT_MAYBE (1 == n);
  70     ASSERT_MAYBE (2 == n);
  71     ASSERT_MAYBE (3 == n);
  72     ASSERT_MAYBE (4 == n);
  73   }
  74 }
  75
  76 void test_string_and_array (int i, struct Arrays *a)
  77 {
  78   {
  79     const char *s = i < 0 ? a->a3 : "1";
  80
  81     int n = __builtin_snprintf (0, 0, "%-s", s);
  82
  83     /* ASSERT (0 <= n && n < 3); */
  84
  85     ASSERT_MAYBE (0 == n);
  86     ASSERT_MAYBE (1 == n);
  87     ASSERT_MAYBE (2 == n);
  88   }
  89
  90   {
  91     const char *s = i < 0 ? "12" : a->a5;
  92
  93     int n = __builtin_snprintf (0, 0, "%-s", s);
  94
  95     /* ASSERT (0 <= n && n < 5); */
  96
  97     ASSERT_MAYBE (0 == n);
  98     ASSERT_MAYBE (1 == n);
  99     ASSERT_MAYBE (2 == n);
 100     ASSERT_MAYBE (3 == n);
 101     ASSERT_MAYBE (4 == n);
 102   }
 103
 104   {
 105     const char *s = i < 0 ? a->a4 : 0 < i ? "12" : a->a5;
 106
 107     int n = __builtin_snprintf (0, 0, "%-s", s);
 108
 109     /* ASSERT (0 <= n && n < 5); */
 110
 111     ASSERT_MAYBE (0 == n);
 112     ASSERT_MAYBE (1 == n);
 113     ASSERT_MAYBE (2 == n);
 114     ASSERT_MAYBE (3 == n);
 115     ASSERT_MAYBE (4 == n);
 116   }
 117 }
 118
 119 /* { dg-final { scan-tree-dump-not "failure_on_line" "optimized"} }
 120    { dg-final { scan-tree-dump-times "keep_call_on_line" 21 "optimized"} } */