glibc/string/tst-endian.c
Stefan Liebler f69f887092 S390: Fix build failure in test string/tst-endian.c with gcc 6.
Building string/tst-endian.c with gcc 6 produces an build warning/error on s390 (big endian machine):
gcc tst-endian.c -c -std=gnu11 -fgnu89-inline  -O2 or -O3 ...
tst-endian.c: In function ‘do_test’:
tst-endian.c:16:30: error: self-comparison always evaluates to false [-Werror=tautological-compare]
    if (htobe16 (be16toh (i)) != i)
                              ^~
...

See definitions of htobexx, bexxtoh in string/endian.h:
...

This patch silences these warnings with DIAG_* macros if build with gcc 6
and newer.

The same warnings occur on little endian machines with the
"htoleXX (leXXtoh (i)) != i" if-statements.

ChangeLog:

	* string/tst-endian.c: Include <libc-internal.h>.
	(do_test): Ignore tautological-compare warnings around
	"htobeXX (beXXtoh (i)) != i" and
	"htoleXX (leXXtoh (i)) != i" if-statements.
2016-01-25 12:44:46 +01:00

136 lines
3.6 KiB
C

#include <byteswap.h>
#include <endian.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdint.h>
#include <libc-internal.h>
#if __GNUC_PREREQ (6, 0)
/* GCC 6.0 warns on big endian systems about:
htobeXX (beXXtoh (i)) != i
warning: self-comparison always evaluates to false [-Wtautological-compare]
because htobeXX(x) and beXXtoh(x) is defined to (x)
in string/endian.h on big endian systems.
The same applies to htoleXX/leXXtoh on little endian systems. */
# define DIAG_IGNORE_NEEDS_COMMENT_TAUTOLOGICAL_COMPARE() \
DIAG_IGNORE_NEEDS_COMMENT (6, "-Wtautological-compare")
#else
# define DIAG_IGNORE_NEEDS_COMMENT_TAUTOLOGICAL_COMPARE()
#endif
static int
do_test (void)
{
int result = 0;
for (uint64_t i = 0; i < (~UINT64_C (0)) >> 2; i = (i << 1) + 3)
{
if (i < UINT64_C (65536))
{
DIAG_PUSH_NEEDS_COMMENT;
DIAG_IGNORE_NEEDS_COMMENT_TAUTOLOGICAL_COMPARE ();
if (htobe16 (be16toh (i)) != i)
{
printf ("htobe16 (be16toh (%" PRIx64 ")) == %" PRIx16 "\n",
i, (uint16_t) htobe16 (be16toh (i)));
result = 1;
}
if (htole16 (le16toh (i)) != i)
{
printf ("htole16 (le16toh (%" PRIx64 ")) == %" PRIx16 "\n",
i, (uint16_t) htole16 (le16toh (i)));
result = 1;
}
DIAG_POP_NEEDS_COMMENT;
uint16_t n[2];
n[__BYTE_ORDER == __LITTLE_ENDIAN] = bswap_16 (i);
n[__BYTE_ORDER == __BIG_ENDIAN] = i;
if (htole16 (i) != n[0])
{
printf ("htole16 (%" PRIx64 ") == %" PRIx16 " != %" PRIx16 "\n",
i, (uint16_t) htole16 (i), n[0]);
result = 1;
}
if (htobe16 (i) != n[1])
{
printf ("htobe16 (%" PRIx64 ") == %" PRIx16 " != %" PRIx16 "\n",
i, (uint16_t) htobe16 (i), n[1]);
result = 1;
}
}
if (i < UINT64_C (4294967296))
{
DIAG_PUSH_NEEDS_COMMENT;
DIAG_IGNORE_NEEDS_COMMENT_TAUTOLOGICAL_COMPARE ();
if (htobe32 (be32toh (i)) != i)
{
printf ("htobe32 (be32toh (%" PRIx64 ")) == %" PRIx32 "\n",
i, (uint32_t) htobe32 (be32toh (i)));
result = 1;
}
if (htole32 (le32toh (i)) != i)
{
printf ("htole32 (le32toh (%" PRIx64 ")) == %" PRIx32 "\n",
i, (uint32_t) htole32 (le32toh (i)));
result = 1;
}
DIAG_POP_NEEDS_COMMENT;
uint32_t n[2];
n[__BYTE_ORDER == __LITTLE_ENDIAN] = bswap_32 (i);
n[__BYTE_ORDER == __BIG_ENDIAN] = i;
if (htole32 (i) != n[0])
{
printf ("htole32 (%" PRIx64 ") == %" PRIx32 " != %" PRIx32 "\n",
i, (uint32_t) htole32 (i), n[0]);
result = 1;
}
if (htobe32 (i) != n[1])
{
printf ("htobe32 (%" PRIx64 ") == %" PRIx32 " != %" PRIx32 "\n",
i, (uint32_t) htobe32 (i), n[1]);
result = 1;
}
}
DIAG_PUSH_NEEDS_COMMENT;
DIAG_IGNORE_NEEDS_COMMENT_TAUTOLOGICAL_COMPARE ();
if (htobe64 (be64toh (i)) != i)
{
printf ("htobe64 (be64toh (%" PRIx64 ")) == %" PRIx64 "\n",
i, htobe64 (be64toh (i)));
result = 1;
}
if (htole64 (le64toh (i)) != i)
{
printf ("htole64 (le64toh (%" PRIx64 ")) == %" PRIx64 "\n",
i, htole64 (le64toh (i)));
result = 1;
}
DIAG_POP_NEEDS_COMMENT;
uint64_t n[2];
n[__BYTE_ORDER == __LITTLE_ENDIAN] = bswap_64 (i);
n[__BYTE_ORDER == __BIG_ENDIAN] = i;
if (htole64 (i) != n[0])
{
printf ("htole64 (%" PRIx64 ") == %" PRIx64 " != %" PRIx64 "\n",
i, htole64 (i), n[0]);
result = 1;
}
if (htobe64 (i) != n[1])
{
printf ("htobe64 (%" PRIx64 ") == %" PRIx64 " != %" PRIx64 "\n",
i, htobe64 (i), n[1]);
result = 1;
}
}
return result;
}
#define TEST_FUNCTION do_test ()
#include "../test-skeleton.c"