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authorJoseph Myers <joseph@codesourcery.com>2015-05-21 23:44:33 +0000
committerJoseph Myers <joseph@codesourcery.com>2015-05-21 23:44:33 +0000
commit9124ccf76abc5a2ffe4603e6424b1dc2b5a5db44 (patch)
treedf43bd150365d7da6bee80df86d59f7bb57c7da3 /sysdeps
parent89f3b6e18c6e7833438789746fcfc2e7189f7cac (diff)
downloadglibc-9124ccf76abc5a2ffe4603e6424b1dc2b5a5db44.tar.gz
Fix lgamma implementations for -Wuninitialized.
If you remove the "override CFLAGS += -Wno-uninitialized" in math/Makefile, you get errors from lgamma implementations of the form: ../sysdeps/ieee754/dbl-64/e_lgamma_r.c: In function '__ieee754_lgamma_r': ../sysdeps/ieee754/dbl-64/e_lgamma_r.c:297:13: error: 'nadj' may be used uninitialized in this function [-Werror=maybe-uninitialized] if(hx<0) r = nadj - r; This is one of the standard kinds of false positive uninitialized warnings: nadj is set under a certain condition, and then later used under the same condition. This patch uses DIAG_* macros to suppress the warning on the use of nadj. The ldbl-128 / ldbl-128ibm implementation has a substantially different structure that avoids this issue. Tested for x86_64. (In fact this patch eliminates the need for that -Wno-uninitialized on x86_64, but I want to test on more architectures before removing it.) * sysdeps/ieee754/dbl-64/e_lgamma_r.c: Include <libc-internal.h>. (__ieee754_lgamma_r): Ignore uninitialized warnings around use of NADJ. * sysdeps/ieee754/flt-32/e_lgammaf_r.c: Include <libc-internal.h>. (__ieee754_lgammaf_r): Ignore uninitialized warnings around use of NADJ. * sysdeps/ieee754/ldbl-96/e_lgammal_r.c: Include <libc-internal.h>. (__ieee754_lgammal_r): Ignore uninitialized warnings around use of NADJ.
Diffstat (limited to 'sysdeps')
-rw-r--r--sysdeps/ieee754/dbl-64/e_lgamma_r.c12
-rw-r--r--sysdeps/ieee754/flt-32/e_lgammaf_r.c12
-rw-r--r--sysdeps/ieee754/ldbl-96/e_lgammal_r.c11
3 files changed, 35 insertions, 0 deletions
diff --git a/sysdeps/ieee754/dbl-64/e_lgamma_r.c b/sysdeps/ieee754/dbl-64/e_lgamma_r.c
index af7d06c82f..fc6f594d62 100644
--- a/sysdeps/ieee754/dbl-64/e_lgamma_r.c
+++ b/sysdeps/ieee754/dbl-64/e_lgamma_r.c
@@ -77,6 +77,7 @@
*
*/
+#include <libc-internal.h>
#include <math.h>
#include <math_private.h>
@@ -294,7 +295,18 @@ __ieee754_lgamma_r(double x, int *signgamp)
} else
/* 2**58 <= x <= inf */
r = x*(__ieee754_log(x)-one);
+ /* NADJ is set for negative arguments but not otherwise,
+ resulting in warnings that it may be used uninitialized
+ although in the cases where it is used it has always been
+ set. */
+ DIAG_PUSH_NEEDS_COMMENT;
+#if __GNUC_PREREQ (4, 7)
+ DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wmaybe-uninitialized");
+#else
+ DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wuninitialized");
+#endif
if(hx<0) r = nadj - r;
+ DIAG_POP_NEEDS_COMMENT;
return r;
}
strong_alias (__ieee754_lgamma_r, __lgamma_r_finite)
diff --git a/sysdeps/ieee754/flt-32/e_lgammaf_r.c b/sysdeps/ieee754/flt-32/e_lgammaf_r.c
index 4743bee438..c0bf4156ff 100644
--- a/sysdeps/ieee754/flt-32/e_lgammaf_r.c
+++ b/sysdeps/ieee754/flt-32/e_lgammaf_r.c
@@ -13,6 +13,7 @@
* ====================================================
*/
+#include <libc-internal.h>
#include <math.h>
#include <math_private.h>
@@ -229,7 +230,18 @@ __ieee754_lgammaf_r(float x, int *signgamp)
} else
/* 2**26 <= x <= inf */
r = x*(__ieee754_logf(x)-one);
+ /* NADJ is set for negative arguments but not otherwise,
+ resulting in warnings that it may be used uninitialized
+ although in the cases where it is used it has always been
+ set. */
+ DIAG_PUSH_NEEDS_COMMENT;
+#if __GNUC_PREREQ (4, 7)
+ DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wmaybe-uninitialized");
+#else
+ DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wuninitialized");
+#endif
if(hx<0) r = nadj - r;
+ DIAG_POP_NEEDS_COMMENT;
return r;
}
strong_alias (__ieee754_lgammaf_r, __lgammaf_r_finite)
diff --git a/sysdeps/ieee754/ldbl-96/e_lgammal_r.c b/sysdeps/ieee754/ldbl-96/e_lgammal_r.c
index 1a95f846ae..0cc35f9252 100644
--- a/sysdeps/ieee754/ldbl-96/e_lgammal_r.c
+++ b/sysdeps/ieee754/ldbl-96/e_lgammal_r.c
@@ -91,6 +91,7 @@
*
*/
+#include <libc-internal.h>
#include <math.h>
#include <math_private.h>
@@ -423,8 +424,18 @@ __ieee754_lgammal_r (long double x, int *signgamp)
else
/* 2**66 <= x <= inf */
r = x * (__ieee754_logl (x) - one);
+ /* NADJ is set for negative arguments but not otherwise, resulting
+ in warnings that it may be used uninitialized although in the
+ cases where it is used it has always been set. */
+ DIAG_PUSH_NEEDS_COMMENT;
+#if __GNUC_PREREQ (4, 7)
+ DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wmaybe-uninitialized");
+#else
+ DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wuninitialized");
+#endif
if (se & 0x8000)
r = nadj - r;
+ DIAG_POP_NEEDS_COMMENT;
return r;
}
strong_alias (__ieee754_lgammal_r, __lgammal_r_finite)