Fix two bugs in the signbit() macro, which was implemented last year:

- It was added to libc instead of libm.  Hopefully no programs rely
  on this mistake.

- It didn't work properly on large long doubles because its argument
  was converted to type double, resulting in undefined behavior.

2 files changed, 64 insertions, 1 deletions

diff --git a/lib/msun/src/math.h b/lib/msun/src/math.h
index 76598e3..b85ef96 100644
--- a/lib/msun/src/math.h
+++ b/lib/msun/src/math.h
@@ -113,7 +113,10 @@ extern const union __nan_un {
 #define	isunordered(x, y)	(isnan(x) || isnan(y))
 #endif /* __MATH_BUILTIN_RELOPS */
 
-#define	signbit(x)	__signbit(x)
+#define	signbit(x)					\
+    ((sizeof (x) == sizeof (float)) ? __signbitf(x)	\
+    : (sizeof (x) == sizeof (double)) ? __signbit(x)	\
+    : __signbitl(x))
 
 typedef	__double_t	double_t;
 typedef	__float_t	float_t;
@@ -215,6 +218,8 @@ int	__isnormalf(float) __pure2;
 int	__isnormal(double) __pure2;
 int	__isnormall(long double) __pure2;
 int	__signbit(double) __pure2;
+int	__signbitf(float) __pure2;
+int	__signbitl(long double) __pure2;
 
 double	acos(double);
 double	asin(double);
diff --git a/lib/msun/src/s_signbit.c b/lib/msun/src/s_signbit.c
new file mode 100644
index 0000000..01eb3ab
--- /dev/null
+++ b/lib/msun/src/s_signbit.c
@@ -0,0 +1,58 @@
+/*-
+ * Copyright (c) 2003 Mike Barcroft <mike@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#include <math.h>
+
+#include "fpmath.h"
+
+int
+__signbit(double d)
+{
+	union IEEEd2bits u;
+
+	u.d = d;
+	return (u.bits.sign);
+}
+
+int
+__signbitf(float f)
+{
+	union IEEEf2bits u;
+
+	u.f = f;
+	return (u.bits.sign);
+}
+
+int
+__signbitl(long double e)
+{
+	union IEEEl2bits u;
+
+	u.e = e;
+	return (u.bits.sign);
+}