Viewing file:  strlenopt-69.c (3.09 KB) -rw-r--r--
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/* PR tree-optimization/90879 - fold zero-equality of strcmp between
a longer string and a smaller array
{ dg-do compile }
{ dg-options "-O2 -Wall -Wno-string-compare -fdump-tree-optimized -ftrack-macro-expansion=0" } */
#include "strlenopt.h"
#define A(expr) \
((expr) \
? (void)0 \
: (__builtin_printf ("assertion failed on line %i: %s\n", \
__LINE__, #expr), \
__builtin_abort ()))
void clobber (void*, ...);
struct S { char a4[4], c; };
extern char a4[4];
extern char b4[4];
/* Verify that comparison of string literals with arrays with unknown
content but size that prevents them from comparing equal is folded
to a constant. */
void test_array_lit (void)
{
A (strcmp (a4, "1234")); clobber (a4);
A (strcmp (a4, "12345")); clobber (a4);
A (strcmp (a4, "123456")); clobber (a4);
A (strcmp ("1234", a4)); clobber (a4);
A (strcmp ("12345", a4)); clobber (a4);
A (strcmp ("123456", a4)); clobber (a4);
}
void test_memarray_lit (struct S *p)
{
#if 0
/* Member arrays not handled due to the fix for PR 92765. */
A (strcmp (p->a4, "1234"));
A (strcmp (p->a4, "12345"));
A (strcmp (p->a4, "123456"));
A (strcmp ("1234", p->a4));
A (strcmp ("12345", p->a4));
A (strcmp ("123456", p->a4));
#endif
}
/* Verify that the equality of empty strings is folded. */
void test_empty_string (void)
{
A (0 == strcmp ("", ""));
*a4 = '\0';
A (0 == strcmp (a4, ""));
A (0 == strcmp ("", a4));
A (0 == strcmp (a4, a4));
char s[8] = "";
A (0 == strcmp (a4, s));
a4[1] = '\0';
b4[1] = '\0';
A (0 == strcmp (a4 + 1, b4 + 1));
a4[2] = '\0';
b4[2] = '\0';
A (0 == strcmp (&a4[2], &b4[2]));
#if 0
/* The following isn't handled yet due to PR 92155. */
clobber (a4, b4);
memset (a4, 0, sizeof a4);
memset (b4, 0, sizeof b4);
A (0 == strcmp (a4, b4));
#endif
}
/* Verify that comparison of dynamically created strings with unknown
arrays is folded. */
void test_array_copy (void)
{
char s[8];
strcpy (s, "1234");
A (strcmp (a4, s));
strcpy (s, "12345");
A (strlen (s) == 5);
A (strcmp (a4, s)); clobber (a4);
strcpy (s, "123456");
A (strcmp (a4, s)); clobber (a4);
strcpy (s, "1234");
A (strcmp (s, a4)); clobber (a4);
strcpy (s, "12345");
A (strcmp (s, a4)); clobber (a4);
strcpy (s, "123456");
A (strcmp (s, a4)); clobber (a4);
}
void test_array_bounded (void)
{
A (strncmp (a4, "12345", 5)); clobber (a4);
A (strncmp ("54321", a4, 5)); clobber (a4);
A (strncmp (a4, "123456", 5)); clobber (a4);
A (strncmp ("654321", a4, 5)); clobber (a4);
}
void test_array_copy_bounded (void)
{
char s[8];
strcpy (s, "12345");
A (strncmp (a4, s, 5)); clobber (a4);
strcpy (s, "54321");
A (strncmp (s, a4, 5)); clobber (a4);
strcpy (s, "123456");
A (strncmp (a4, s, 5)); clobber (a4);
strcpy (s, "654321");
A (strncmp (s, a4, 5)); clobber (a4);
}
/* { dg-final { scan-tree-dump-not "abort|strcmp|strncmp" "optimized" } } */
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