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 36a5090..515aa1e 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 8c61198..d8f4fc6 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 4000a93..7c5d1cc 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;