gcc/testsuite/gcc.dg/memcmp-4.c

   1 /* PR middle-end/78257 - missing memcmp optimization with constant arrays
   2    { dg-do compile }
   3    { dg-options "-O -Wall -fdump-tree-optimized" } */
   4
   5 typedef __INT8_TYPE__  int8_t;
   6 typedef __INT16_TYPE__ int16_t;
   7 typedef __INT32_TYPE__ int32_t;
   8 typedef __SIZE_TYPE__  size_t;
   9
  10 extern int memcmp (const void*, const void*, size_t);
  11
  12 /* Verify that initializers for flexible array members are handled
  13    correctly.  */
  14
  15 struct Si16_x
  16 {
  17   int16_t n, a[];
  18 };
  19
  20 const struct Si16_x si16_4 =
  21   {
  22    0x1112, { 0x2122, 0x3132, 0x4142 }
  23   };
  24
  25 const char si16_4_rep[] =
  26   {
  27    0x12, 0x11, 0x22, 0x21, 0x32, 0x31, 0x42, 0x41
  28   };
  29
  30 void eq_si16_x (void)
  31 {
  32   int n = 0, b = sizeof si16_4_rep;
  33   const char *p = (const char*)&si16_4, *q = si16_4_rep;
  34
  35   n += memcmp (p,      q,      b);
  36   n += memcmp (p + 1,  q + 1,  b - 1);
  37   n += memcmp (p + 2,  q + 2,  b - 2);
  38   n += memcmp (p + 3,  q + 3,  b - 3);
  39   n += memcmp (p + 4,  q + 4,  b - 4);
  40   n += memcmp (p + 5,  q + 5,  b - 5);
  41   n += memcmp (p + 6,  q + 6,  b - 6);
  42   n += memcmp (p + 7,  q + 7,  b - 7);
  43   n += memcmp (p + 8,  q + 8,  b - 8);
  44
  45   p = (const char*)&si16_4.n;
  46
  47   n += memcmp (p,      q,          b);
  48   n += memcmp (p + 1,  q + 1,  b - 1);
  49   n += memcmp (p + 2,  q + 2,  b - 2);
  50   n += memcmp (p + 3,  q + 3,  b - 3);
  51   n += memcmp (p + 4,  q + 4,  b - 4);
  52   n += memcmp (p + 5,  q + 5,  b - 5);
  53   n += memcmp (p + 6,  q + 6,  b - 6);
  54   n += memcmp (p + 7,  q + 7,  b - 7);
  55   n += memcmp (p + 8,  q + 8,  b - 8);
  56
  57   p = (const char*)si16_4.a;
  58   q = si16_4_rep + 2;
  59
  60   n += memcmp (p,      q,      b - 2);
  61   n += memcmp (p + 1,  q + 1,  b - 3);
  62   n += memcmp (p + 2,  q + 2,  b - 4);
  63   n += memcmp (p + 3,  q + 3,  b - 5);
  64   n += memcmp (p + 4,  q + 4,  b - 6);
  65   n += memcmp (p + 5,  q + 5,  b - 7);
  66   n += memcmp (p + 6,  q + 6,  b - 8);
  67
  68   p = (const char*)&si16_4.a[1];
  69   q = si16_4_rep + 4;
  70
  71   n += memcmp (p,      q,      b - 4);
  72   n += memcmp (p + 1,  q + 1,  b - 5);
  73   n += memcmp (p + 2,  q + 2,  b - 6);
  74   n += memcmp (p + 3,  q + 3,  b - 7);
  75   n += memcmp (p + 4,  q + 4,  b - 8);
  76
  77   if (n != 0)
  78     __builtin_abort ();
  79 }
  80
  81 /* { dg-final { scan-tree-dump-not "abort" "optimized" } } */