Make nextafter, nexttoward set errno (bug 6799).

nextafter and nexttoward fail to set errno on overflow and underflow.
This patch makes them do so in cases that should include all the cases
where such errno setting is required by glibc's goals for when to set
errno (but not all cases of underflow where the result is nonzero and
so glibc's goals do not require errno setting).

Tested for x86_64, x86, mips64 and powerpc.

	[BZ #6799]
	* math/s_nextafter.c: Include <errno.h>.
	(__nextafter): Set errno on overflow and underflow.
	* math/s_nexttowardf.c: Include <errno.h>.
	(__nexttowardf): Set errno on overflow and underflow.
	* sysdeps/i386/fpu/s_nextafterl.c: Include <errno.h>.
	(__nextafterl): Set errno on overflow and underflow.
	* sysdeps/i386/fpu/s_nexttoward.c: Include <errno.h>.
	(__nexttoward): Set errno on overflow and underflow.
	* sysdeps/i386/fpu/s_nexttowardf.c: Include <errno.h>.
	(__nexttowardf): Set errno on overflow and underflow.
	* sysdeps/ieee754/flt-32/s_nextafterf.c: Include <errno.h>.
	(__nextafterf): Set errno on overflow and underflow.
	* sysdeps/ieee754/ldbl-128/s_nextafterl.c: Include <errno.h>.
	(__nextafterl): Set errno on overflow and underflow.
	* sysdeps/ieee754/ldbl-128/s_nexttoward.c: Include <errno.h>.
	(__nexttoward): Set errno on overflow and underflow.
	* sysdeps/ieee754/ldbl-128/s_nexttowardf.c: Include <errno.h>.
	(__nexttowardf): Set errno on overflow and underflow.
	* sysdeps/ieee754/ldbl-128ibm/s_nextafterl.c: Include <errno.h>.
	(__nextafterl): Set errno on overflow and underflow.
	* sysdeps/ieee754/ldbl-128ibm/s_nexttoward.c: Include <errno.h>.
	(__nexttoward): Set errno on overflow and underflow.
	* sysdeps/ieee754/ldbl-128ibm/s_nexttowardf.c: Include <errno.h>.
	(__nexttowardf): Set errno on overflow and underflow.
	* sysdeps/ieee754/ldbl-96/s_nexttoward.c: Include <errno.h>.
	(__nexttoward): Set errno on overflow and underflow.
	* sysdeps/ieee754/ldbl-96/s_nexttowardf.c: Include <errno.h>.
	(__nexttowardf): Set errno on overflow and underflow.
	* sysdeps/ieee754/ldbl-opt/s_nexttowardfd.c: Include <errno.h>.
	(__nldbl_nexttowardf): Set errno on overflow and underflow.
	* sysdeps/m68k/m680x0/fpu/s_nextafterl.c: Include <errno.h>.
	(__nextafterl): Set errno on overflow and underflow.
	* math/libm-test.inc (nextafter_test_data): Do not allow errno
	setting to be missing on overflow.  Add more tests.
	(nexttoward_test_data): Likewise.

3 files changed, 11 insertions, 0 deletions

diff --git a/sysdeps/ieee754/ldbl-128ibm/s_nextafterl.c b/sysdeps/ieee754/ldbl-128ibm/s_nextafterl.c
index 36a5090693..515aa1ef5b 100644
--- a/sysdeps/ieee754/ldbl-128ibm/s_nextafterl.c
+++ b/sysdeps/ieee754/ldbl-128ibm/s_nextafterl.c
@@ -24,6 +24,7 @@ static char rcsid[] = "$NetBSD: $";
  *   Special cases:
  */
 
+#include <errno.h>
 #include <float.h>
 #include <math.h>
 #include <math_private.h>
@@ -69,6 +70,7 @@ long double __nextafterl(long double x, long double y)
 	    if((hx==0xffefffffffffffffLL)&&(lx==0xfc8ffffffffffffeLL)) {
 	      u = x+x;	/* overflow, return -inf */
 	      math_force_eval (u);
+	      __set_errno (ERANGE);
 	      return y;
 	    }
 	    if (hx >= 0x7ff0000000000000LL) {
@@ -83,6 +85,7 @@ long double __nextafterl(long double x, long double y)
 		  || (hx < 0 && lx > 1)) {
 		u = u * u;
 		math_force_eval (u);		/* raise underflow flag */
+		__set_errno (ERANGE);
 	      }
 	      return x;
 	    }
@@ -108,6 +111,7 @@ long double __nextafterl(long double x, long double y)
 	    if((hx==0x7fefffffffffffffLL)&&(lx==0x7c8ffffffffffffeLL)) {
 	      u = x+x;	/* overflow, return +inf */
 	      math_force_eval (u);
+	      __set_errno (ERANGE);
 	      return y;
 	    }
 	    if ((uint64_t) hx >= 0xfff0000000000000ULL) {
@@ -122,6 +126,7 @@ long double __nextafterl(long double x, long double y)
 		  || (hx < 0 && lx >= 0)) {
 		u = u * u;
 		math_force_eval (u);		/* raise underflow flag */
+		__set_errno (ERANGE);
 	      }
 	      if (x == 0.0L)	/* handle negative LDBL_TRUE_MIN case */
 		x = -0.0L;
diff --git a/sysdeps/ieee754/ldbl-128ibm/s_nexttoward.c b/sysdeps/ieee754/ldbl-128ibm/s_nexttoward.c
index 8c6119825e..d8f4fc6523 100644
--- a/sysdeps/ieee754/ldbl-128ibm/s_nexttoward.c
+++ b/sysdeps/ieee754/ldbl-128ibm/s_nexttoward.c
@@ -25,6 +25,7 @@ static char rcsid[] = "$NetBSD: $";
  *   Special cases:
  */
 
+#include <errno.h>
 #include <math.h>
 #include <math_private.h>
 #include <math_ldbl_opt.h>
@@ -76,10 +77,12 @@ double __nexttoward(double x, long double y)
 	if(hy>=0x7ff00000) {
 	  double u = x+x;			/* overflow  */
 	  math_force_eval (u);
+	  __set_errno (ERANGE);
 	}
 	if(hy<0x00100000) {
 	    double u = x*x;			/* underflow */
 	    math_force_eval (u);		/* raise underflow flag */
+	    __set_errno (ERANGE);
 	}
 	INSERT_WORDS(x,hx,lx);
 	return x;
diff --git a/sysdeps/ieee754/ldbl-128ibm/s_nexttowardf.c b/sysdeps/ieee754/ldbl-128ibm/s_nexttowardf.c
index 4000a93e69..7c5d1cc112 100644
--- a/sysdeps/ieee754/ldbl-128ibm/s_nexttowardf.c
+++ b/sysdeps/ieee754/ldbl-128ibm/s_nexttowardf.c
@@ -18,6 +18,7 @@
 static char rcsid[] = "$NetBSD: $";
 #endif
 
+#include <errno.h>
 #include <math.h>
 #include <math_private.h>
 #include <math_ldbl_opt.h>
@@ -65,10 +66,12 @@ float __nexttowardf(float x, long double y)
 	if(hy>=0x7f800000) {
 	  float u = x+x;		/* overflow  */
 	  math_force_eval (u);
+	  __set_errno (ERANGE);
 	}
 	if(hy<0x00800000) {		/* underflow */
 	    float u = x*x;
 	    math_force_eval (u);	/* raise underflow flag */
+	    __set_errno (ERANGE);
 	}
 	SET_FLOAT_WORD(x,hx);
 	return x;