gcc/testsuite/gcc.dg/Wstringop-overflow-76-novec.c

   1 /* Verify warnings and notes for MAX_EXPRs involving either pointers
   2    to distinct objects or one to a known object and the other to
   3    an unknown one.  Unlike for the same object, for unrelated objects
   4    the expected warnings and notes are the same as for MIN_EXPR: when
   5    the order of the objects in the address space cannot be determined
   6    the larger of them is assumed to be used.  (This is different for
   7    distinct struct members where the order is given.)
   8    The relational expressions are strictly invalid but that should be
   9    diagnosed by a separate warning.
  10    { dg-do compile }
  11    { dg-options "-O2 -Wno-array-bounds -fno-tree-vectorize" } */
  12
  13 #define MAX(p, q) ((p) > (q) ? (p) : (q))
  14
  15 /* Verify that even for MAX_EXPR and like for MIN_EXPR, the note points
  16    to the larger of the two objects and mentions the offset into it
  17    (although the offset might be better included in the warning).  */
  18 extern char a3[3];
  19 extern char a5[5];  // { dg-message "at offset 5 into destination object 'a5' of size 5" "note" }
  20
  21 void max_a3_a5 (int i)
  22 {
  23   char *p = a3 + i;
  24   char *q = a5 + i;
  25
  26   /* The relational expression below is invalid and should be diagnosed
  27      by its own warning independently of -Wstringop-overflow.  */
  28   char *d = MAX (p, q);
  29
  30   d[2] = 0;
  31   d[3] = 0;
  32   d[4] = 0;
  33   d[5] = 0;         // { dg-warning "writing 1 byte into a region of size 0" }
  34 }
  35
  36
  37 // Same as above but with the larger array as the first MAX_EXPR operand.
  38 extern char b4[4];
  39 extern char b6[6];  // { dg-message "at offset 6 into destination object 'b6' of size 6" "note" }
  40
  41 void max_b6_b4 (int i)
  42 {
  43   char *p = b6 + i;
  44   char *q = b4 + i;
  45   char *d = MAX (p, q);
  46
  47   d[3] = 0;
  48   d[4] = 0;
  49   d[5] = 0;
  50   d[6] = 0;         // { dg-warning "writing 1 byte into a region of size 0" }
  51 }
  52
  53 struct A3_5
  54 {
  55   char a3[3];  // { dg-message "at offset 3 into destination object 'a3' of size 3" "pr??????" { xfail *-*-* } }
  56   char a5[5];  // { dg-message "at offset 5 into destination object 'a5' of size 5" "note" }
  57 };
  58
  59 void max_A3_A5 (int i, struct A3_5 *pa3_5)
  60 {
  61   char *p = pa3_5->a3 + i;
  62   char *q = pa3_5->a5 + i;
  63
  64   char *d = MAX (p, q);
  65   d[2] = 0;
  66   d[3] = 0;         // { dg-warning "writing 1 byte into a region of size 0" "pr??????" { xfail *-*-* } }
  67   d[4] = 0;
  68   d[5] = 0;         // { dg-warning "writing 1 byte into a region of size 0" }
  69 }
  70
  71
  72 struct B4_B6
  73 {
  74   char b4[4];
  75   char b6[6];       // { dg-message "at offset 6 into destination object 'b6' of size 6" "note" }
  76 };
  77
  78 void max_B6_B4 (int i, struct B4_B6 *pb4_b6)
  79 {
  80   char *p = pb4_b6->b6 + i;
  81   char *q = pb4_b6->b4 + i;
  82   char *d = MAX (p, q);
  83
  84   d[3] = 0;
  85   d[4] = 0;
  86   d[5] = 0;
  87   d[6] = 0;         // { dg-warning "writing 1 byte into a region of size 0" }
  88 }