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S390: Fix build failure in test string/tst-endian.c with gcc 6.

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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.
This commit is contained in:
Stefan Liebler 2016-01-25 12:44:46 +01:00
parent c34ae92056
commit f69f887092
2 changed files with 30 additions and 0 deletions
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7
ChangeLog
View File

@ -1,3 +1,10 @@
2016-01-22 Stefan Liebler <stli@linux.vnet.ibm.com>
* 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.
2016-01-24 David S. Miller <davem@davemloft.net> 2016-01-24 David S. Miller <davem@davemloft.net>
* sysdeps/sparc/sparc32/fpu/e_sqrtl.c: New file. * sysdeps/sparc/sparc32/fpu/e_sqrtl.c: New file.

23
string/tst-endian.c
View File

@ -3,6 +3,20 @@
#include <inttypes.h> #include <inttypes.h>
#include <stdio.h> #include <stdio.h>
#include <stdint.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 static int
do_test (void) do_test (void)
@ -13,6 +27,8 @@ do_test (void)
{ {
if (i < UINT64_C (65536)) if (i < UINT64_C (65536))
{ {
DIAG_PUSH_NEEDS_COMMENT;
DIAG_IGNORE_NEEDS_COMMENT_TAUTOLOGICAL_COMPARE ();
if (htobe16 (be16toh (i)) != i) if (htobe16 (be16toh (i)) != i)
{ {
printf ("htobe16 (be16toh (%" PRIx64 ")) == %" PRIx16 "\n", printf ("htobe16 (be16toh (%" PRIx64 ")) == %" PRIx16 "\n",
@ -25,6 +41,7 @@ do_test (void)
i, (uint16_t) htole16 (le16toh (i))); i, (uint16_t) htole16 (le16toh (i)));
result = 1; result = 1;
} }
DIAG_POP_NEEDS_COMMENT;
uint16_t n[2]; uint16_t n[2];
n[__BYTE_ORDER == __LITTLE_ENDIAN] = bswap_16 (i); n[__BYTE_ORDER == __LITTLE_ENDIAN] = bswap_16 (i);
@ -45,6 +62,8 @@ do_test (void)
if (i < UINT64_C (4294967296)) if (i < UINT64_C (4294967296))
{ {
DIAG_PUSH_NEEDS_COMMENT;
DIAG_IGNORE_NEEDS_COMMENT_TAUTOLOGICAL_COMPARE ();
if (htobe32 (be32toh (i)) != i) if (htobe32 (be32toh (i)) != i)
{ {
printf ("htobe32 (be32toh (%" PRIx64 ")) == %" PRIx32 "\n", printf ("htobe32 (be32toh (%" PRIx64 ")) == %" PRIx32 "\n",
@ -57,6 +76,7 @@ do_test (void)
i, (uint32_t) htole32 (le32toh (i))); i, (uint32_t) htole32 (le32toh (i)));
result = 1; result = 1;
} }
DIAG_POP_NEEDS_COMMENT;
uint32_t n[2]; uint32_t n[2];
n[__BYTE_ORDER == __LITTLE_ENDIAN] = bswap_32 (i); n[__BYTE_ORDER == __LITTLE_ENDIAN] = bswap_32 (i);
@ -75,6 +95,8 @@ do_test (void)
} }
} }
DIAG_PUSH_NEEDS_COMMENT;
DIAG_IGNORE_NEEDS_COMMENT_TAUTOLOGICAL_COMPARE ();
if (htobe64 (be64toh (i)) != i) if (htobe64 (be64toh (i)) != i)
{ {
printf ("htobe64 (be64toh (%" PRIx64 ")) == %" PRIx64 "\n", printf ("htobe64 (be64toh (%" PRIx64 ")) == %" PRIx64 "\n",
@ -87,6 +109,7 @@ do_test (void)
i, htole64 (le64toh (i))); i, htole64 (le64toh (i)));
result = 1; result = 1;
} }
DIAG_POP_NEEDS_COMMENT;
uint64_t n[2]; uint64_t n[2];
n[__BYTE_ORDER == __LITTLE_ENDIAN] = bswap_64 (i); n[__BYTE_ORDER == __LITTLE_ENDIAN] = bswap_64 (i);