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, 20 insertions, 6 deletions

diff --git a/math/libm-test.inc b/math/libm-test.inc
index ace51c977e..1267b817e7 100644
--- a/math/libm-test.inc
+++ b/math/libm-test.inc
@@ -9850,9 +9850,13 @@ static const struct test_ff_f_data nextafter_test_data[] =
     TEST_ff_f (nextafter, 1.1L, qnan_value, qnan_value, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
     TEST_ff_f (nextafter, qnan_value, qnan_value, qnan_value, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
 
-    /* Bug 6799: errno setting may be missing.  */
-    TEST_ff_f (nextafter, max_value, plus_infty, plus_infty, INEXACT_EXCEPTION|OVERFLOW_EXCEPTION),
-    TEST_ff_f (nextafter, -max_value, minus_infty, minus_infty, INEXACT_EXCEPTION|OVERFLOW_EXCEPTION),
+    TEST_ff_f (nextafter, max_value, plus_infty, plus_infty, INEXACT_EXCEPTION|OVERFLOW_EXCEPTION|ERRNO_ERANGE),
+    TEST_ff_f (nextafter, -max_value, minus_infty, minus_infty, INEXACT_EXCEPTION|OVERFLOW_EXCEPTION|ERRNO_ERANGE),
+
+    TEST_ff_f (nextafter, min_subnorm_value, 0, 0, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION|ERRNO_ERANGE),
+    TEST_ff_f (nextafter, min_subnorm_value, minus_zero, 0, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION|ERRNO_ERANGE),
+    TEST_ff_f (nextafter, -min_subnorm_value, 0, minus_zero, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION|ERRNO_ERANGE),
+    TEST_ff_f (nextafter, -min_subnorm_value, minus_zero, minus_zero, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION|ERRNO_ERANGE),
 
 #ifdef TEST_LDOUBLE
     // XXX Enable once gcc is fixed.
@@ -9894,9 +9898,13 @@ static const struct test_ff_f_data_nexttoward nexttoward_test_data[] =
     TEST_ff_f (nexttoward, 1.1L, qnan_value, qnan_value, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
     TEST_ff_f (nexttoward, qnan_value, qnan_value, qnan_value, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
 
-    /* Bug 6799: errno setting may be missing.  */
-    TEST_ff_f (nexttoward, max_value, plus_infty, plus_infty, INEXACT_EXCEPTION|OVERFLOW_EXCEPTION),
-    TEST_ff_f (nexttoward, -max_value, minus_infty, minus_infty, INEXACT_EXCEPTION|OVERFLOW_EXCEPTION),
+    TEST_ff_f (nexttoward, max_value, plus_infty, plus_infty, INEXACT_EXCEPTION|OVERFLOW_EXCEPTION|ERRNO_ERANGE),
+    TEST_ff_f (nexttoward, -max_value, minus_infty, minus_infty, INEXACT_EXCEPTION|OVERFLOW_EXCEPTION|ERRNO_ERANGE),
+
+    TEST_ff_f (nexttoward, min_subnorm_value, 0, 0, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION|ERRNO_ERANGE),
+    TEST_ff_f (nexttoward, min_subnorm_value, minus_zero, 0, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION|ERRNO_ERANGE),
+    TEST_ff_f (nexttoward, -min_subnorm_value, 0, minus_zero, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION|ERRNO_ERANGE),
+    TEST_ff_f (nexttoward, -min_subnorm_value, minus_zero, minus_zero, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION|ERRNO_ERANGE),
 
 #ifdef TEST_FLOAT
     TEST_ff_f (nexttoward, 1.0, 1.1L, 0x1.000002p0, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
diff --git a/math/s_nextafter.c b/math/s_nextafter.c
index 28962e52a7..dfa5e860c4 100644
--- a/math/s_nextafter.c
+++ b/math/s_nextafter.c
@@ -25,6 +25,7 @@ static char rcsid[] = "$NetBSD: s_nextafter.c,v 1.8 1995/05/10 20:47:58 jtc Exp
 #define __nexttoward __internal___nexttoward
 #define nexttoward __internal_nexttoward
 
+#include <errno.h>
 #include <math.h>
 #include <math_private.h>
 #include <float.h>
@@ -72,10 +73,12 @@ double __nextafter(double x, 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/math/s_nexttowardf.c b/math/s_nexttowardf.c
index 06350d47bf..30cd81b454 100644
--- a/math/s_nexttowardf.c
+++ b/math/s_nexttowardf.c
@@ -20,6 +20,7 @@
  *   Special cases:
  */
 
+#include <errno.h>
 #include <math.h>
 #include <math_private.h>
 #include <float.h>
@@ -61,10 +62,12 @@ 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) {
 	    float u = x*x;			/* underflow */
 	    math_force_eval (u);		/* raise underflow flag */
+	    __set_errno (ERANGE);
 	}
 	SET_FLOAT_WORD(x,hx);
 	return x;