gcc/testsuite/gcc.dg/strlenopt-20.c

   1 /* { dg-do run } */
   2 /* { dg-options "-O2 -fdump-tree-strlen" } */
   3
   4 #include "strlenopt.h"
   5
   6 __attribute__((noinline, noclone)) const char *
   7 fn1 (int x, int y)
   8 {
   9   const char *p;
  10   switch (x)
  11     {
  12     case 0:
  13       p = "abcd";
  14       /* Prevent cswitch optimization.  */
  15       asm volatile ("" : : : "memory");
  16       break;
  17     case 1:
  18       p = "efgh";
  19       break;
  20     case 2:
  21       p = "ijkl";
  22       break;
  23     default:
  24       p = "mnop";
  25       break;
  26     }
  27   if (y)
  28     /* strchr should be optimized into p + 4 here.  */
  29     return strchr (p, '\0');
  30   else
  31     /* and strlen into 3.  */
  32     return p + strlen (p + 1);
  33 }
  34
  35 __attribute__((noinline, noclone)) size_t
  36 fn2 (char *p, char *q)
  37 {
  38   size_t l;
  39   /* Both strcpy calls can be optimized into memcpy, strlen needs to stay.  */
  40   strcpy (p, "abc");
  41   p[3] = 'd';
  42   l = strlen (p);
  43   strcpy (q, p);
  44   return l;
  45 }
  46
  47 __attribute__((noinline, noclone)) char *
  48 fn3 (char *p)
  49 {
  50   char *c;
  51   /* The strcpy call can be optimized into memcpy, strchr needs to stay,
  52      strcat is optimized into memcpy.  */
  53   strcpy (p, "abc");
  54   p[3] = 'd';
  55   c = strchr (p, '\0');
  56   strcat (p, "efgh");
  57   return c;
  58 }
  59
  60 int
  61 main ()
  62 {
  63   int i;
  64   char buf[64], buf2[64];
  65   for (i = 0; i < 5; i++)
  66     {
  67       const char *p = "abcdefghijklmnop" + (i < 3 ? i : 3) * 4;
  68       const char *q;
  69       q = fn1 (i, 1);
  70       if (memcmp (q - 4, p, 4) != 0 || q[0] != '\0')
  71         abort ();
  72       q = fn1 (i, 0);
  73       if (memcmp (q - 3, p, 4) != 0 || q[1] != '\0')
  74         abort ();
  75     }
  76   memset (buf, '\0', sizeof buf);
  77   memset (buf + 4, 'z', 2);
  78   if (fn2 (buf, buf2) != 6
  79       || memcmp (buf, "abcdzz", 7) != 0
  80       || memcmp (buf2, "abcdzz", 7) != 0)
  81     abort ();
  82   memset (buf, '\0', sizeof buf);
  83   memset (buf + 4, 'z', 2);
  84   if (fn3 (buf) != buf + 6 || memcmp (buf, "abcdzzefgh", 11) != 0)
  85     abort ();
  86   return 0;
  87 }
  88
  89 /* { dg-final { scan-tree-dump-times "strlen \\(" 2 "strlen" } } */
  90 /* { dg-final { scan-tree-dump-times "memcpy \\(" 4 "strlen" } } */
  91 /* { dg-final { scan-tree-dump-times "strcpy \\(" 0 "strlen" } } */
  92 /* { dg-final { scan-tree-dump-times "strcat \\(" 0 "strlen" } } */
  93 /* { dg-final { scan-tree-dump-times "strchr \\(" 0 "strlen" } } */
  94 /* { dg-final { scan-tree-dump-times "stpcpy \\(" 0 "strlen" } } */