gcc/testsuite/gcc.dg/strlenopt-7.c

   1 /* { dg-do run } */
   2 /* { dg-options "-O2 -fdump-tree-strlen -fdump-tree-optimized" } */
   3
   4 #include "strlenopt.h"
   5
   6 char buf[64];
   7
   8 __attribute__((noinline, noclone)) size_t
   9 foo (void)
  10 {
  11   char *p = memcpy (buf, "abcdefgh", 9);
  12   /* This store can be optimized away as... */
  13   *p = '\0';
  14   /* ... the following strcat can be optimized into memcpy,
  15      which overwrites that '\0'.  */
  16   strcat (p, "ijk");
  17   /* This should be optimized into return 3.  */
  18   return strlen (p);
  19 }
  20
  21 __attribute__((noinline, noclone)) size_t
  22 bar (char *p)
  23 {
  24   char *r = strchr (p, '\0');
  25   /* This store shouldn't be optimized away, because we
  26      want to crash if p is e.g. a string literal.  */
  27   *r = '\0';
  28   /* This strlen can be optimized into 0.  */
  29   return strlen (r);
  30 }
  31
  32 int
  33 main ()
  34 {
  35   char *volatile p = buf;
  36   if (foo () != 3 || memcmp (buf, "ijk\0efgh\0", 10) != 0)
  37     abort ();
  38   if (bar (p) != 0 || memcmp (buf, "ijk\0efgh\0", 10) != 0)
  39     abort ();
  40   return 0;
  41 }
  42
  43 /* { dg-final { scan-tree-dump-times "strlen \\(" 1 "strlen" } } */
  44 /* { dg-final { scan-tree-dump-times "memcpy \\(" 2 "strlen" } } */
  45 /* { dg-final { scan-tree-dump-times "strcpy \\(" 0 "strlen" } } */
  46 /* { dg-final { scan-tree-dump-times "strcat \\(" 0 "strlen" } } */
  47 /* { dg-final { scan-tree-dump-times "strchr \\(" 0 "strlen" } } */
  48 /* { dg-final { scan-tree-dump-times "stpcpy \\(" 0 "strlen" } } */
  49 /* { dg-final { scan-tree-dump-times "\\*r_\[0-9\]* = 0;" 1 "strlen" } } */
  50 /* { dg-final { scan-tree-dump-times "return 3;" 1 "optimized" } } */
  51 /* { dg-final { scan-tree-dump-times "return 0;" 2 "optimized" } } */