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