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[PATCHv3] S390: Fix build failure in test string/tst-endian.c with gcc 6.
- From: Stefan Liebler <stli at linux dot vnet dot ibm dot com>
- To: libc-alpha at sourceware dot org
- Date: Fri, 22 Jan 2016 13:28:53 +0100
- Subject: [PATCHv3] S390: Fix build failure in test string/tst-endian.c with gcc 6.
- Authentication-results: sourceware.org; auth=none
- References: <n7qj1p$1em$1 at ger dot gmane dot org> <alpine dot DEB dot 2 dot 10 dot 1601211402380 dot 21113 at digraph dot polyomino dot org dot uk> <n7r1iu$tdi$1 at ger dot gmane dot org> <20160121164415 dot GI14840 at vapier dot lan>
On 01/21/2016 05:44 PM, Mike Frysinger wrote:
On 21 Jan 2016 17:38, Stefan Liebler wrote:
This patch suppresses these warnings with DIAG_* macros.
The conditional #if __GNUC_PREREQ (6, 0) is needed, because an older gcc
would warn about:
tst-endian.c: In function âdo_testâ:
tst-endian.c:18:4: warning: unknown option after â#pragma GCC
diagnosticâ kind [-Wpragmas]
DIAG_IGNORE_NEEDS_COMMENT (6, "-Wtautological-compare");
^
you can at least do it once at the top via a local define:
/* big comment block */
#if __GNUC_PREREQ (6, 0)
# define DIAG_IGNORE_NEEDS_COMMENT_AUTOLOGICAL_COMPARE() \
DIAG_IGNORE_NEEDS_COMMENT (6, "-Wtautological-compare");
#else
# define DIAG_IGNORE_NEEDS_COMMENT_AUTOLOGICAL_COMPARE()
#endif
then the inline usage is simple
-mike
That's a good point.
Here is the updated patch.
Ok to commit?
Bye Stefan
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.
diff --git a/string/tst-endian.c b/string/tst-endian.c
index 8684bb2..7d39131 100644
--- a/string/tst-endian.c
+++ b/string/tst-endian.c
@@ -3,6 +3,20 @@
#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)
@@ -13,6 +27,8 @@ do_test (void)
{
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",
@@ -25,6 +41,7 @@ do_test (void)
i, (uint16_t) htole16 (le16toh (i)));
result = 1;
}
+ DIAG_POP_NEEDS_COMMENT;
uint16_t n[2];
n[__BYTE_ORDER == __LITTLE_ENDIAN] = bswap_16 (i);
@@ -45,6 +62,8 @@ do_test (void)
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",
@@ -57,6 +76,7 @@ do_test (void)
i, (uint32_t) htole32 (le32toh (i)));
result = 1;
}
+ DIAG_POP_NEEDS_COMMENT;
uint32_t n[2];
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)
{
printf ("htobe64 (be64toh (%" PRIx64 ")) == %" PRIx64 "\n",
@@ -87,6 +109,7 @@ do_test (void)
i, htole64 (le64toh (i)));
result = 1;
}
+ DIAG_POP_NEEDS_COMMENT;
uint64_t n[2];
n[__BYTE_ORDER == __LITTLE_ENDIAN] = bswap_64 (i);