Module Name: src
Committed By: riastradh
Date: Sat May 11 02:07:54 UTC 2024
Modified Files:
src/lib/libm/src: s_nexttoward.c
src/tests/lib/libm: t_next.c
Log Message:
nexttoward(3): Fix high-word test on small positive subnormals.
By this point in the logic, x can't be zero, so it's either positive
or negative.
The high word hx, however, can be zero, when x is a small positive
subnormal. This means x is a small positive subnormal, so if x > y
we are computing nextDown, and if x < y we are computing nextUp.
hx is a (signed 32-bit) integer, not a double floating-point number,
so it's a little silly to compare hx > 0.0. But that on its own
isn't enough to trigger the bug because all signed 32-bit integers
can be represented by double on all NetBSD architectures.
PR lib/58236
To generate a diff of this commit:
cvs rdiff -u -r1.2 -r1.3 src/lib/libm/src/s_nexttoward.c
cvs rdiff -u -r1.5 -r1.6 src/tests/lib/libm/t_next.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/lib/libm/src/s_nexttoward.c
diff -u src/lib/libm/src/s_nexttoward.c:1.2 src/lib/libm/src/s_nexttoward.c:1.3
--- src/lib/libm/src/s_nexttoward.c:1.2 Wed Aug 21 13:03:56 2013
+++ src/lib/libm/src/s_nexttoward.c Sat May 11 02:07:53 2024
@@ -1,4 +1,4 @@
-/* $NetBSD: s_nexttoward.c,v 1.2 2013/08/21 13:03:56 martin Exp $ */
+/* $NetBSD: s_nexttoward.c,v 1.3 2024/05/11 02:07:53 riastradh Exp $ */
/* @(#)s_nextafter.c 5.1 93/09/24 */
/*
@@ -13,7 +13,7 @@
*/
#include <sys/cdefs.h>
-__RCSID("$NetBSD: s_nexttoward.c,v 1.2 2013/08/21 13:03:56 martin Exp $");
+__RCSID("$NetBSD: s_nexttoward.c,v 1.3 2024/05/11 02:07:53 riastradh Exp $");
/*
* We assume that a long double has a 15-bit exponent. On systems
@@ -71,7 +71,7 @@ nexttoward(double x, long double y)
return x; /* raise underflow flag */
}
- if ((hx > 0.0) ^ (x < y)) { /* x -= ulp */
+ if ((hx >= 0) ^ (x < y)) { /* x -= ulp */
if (lx == 0) hx -= 1;
lx -= 1;
} else { /* x += ulp */
Index: src/tests/lib/libm/t_next.c
diff -u src/tests/lib/libm/t_next.c:1.5 src/tests/lib/libm/t_next.c:1.6
--- src/tests/lib/libm/t_next.c:1.5 Sat May 11 01:44:12 2024
+++ src/tests/lib/libm/t_next.c Sat May 11 02:07:54 2024
@@ -1,4 +1,4 @@
-/* $NetBSD: t_next.c,v 1.5 2024/05/11 01:44:12 riastradh Exp $ */
+/* $NetBSD: t_next.c,v 1.6 2024/05/11 02:07:54 riastradh Exp $ */
/*-
* Copyright (c) 2024 The NetBSD Foundation, Inc.
@@ -27,7 +27,7 @@
*/
#include <sys/cdefs.h>
-__RCSID("$NetBSD: t_next.c,v 1.5 2024/05/11 01:44:12 riastradh Exp $");
+__RCSID("$NetBSD: t_next.c,v 1.6 2024/05/11 02:07:54 riastradh Exp $");
#include <atf-c.h>
#include <float.h>
@@ -391,9 +391,6 @@ ATF_TC_BODY(next_near_0, tc)
#endif
};
-#ifdef __HAVE_LONG_DOUBLE
- atf_tc_expect_fail("PR 58236: nexttoward(3) is broken on subnormals");
-#endif
check(x, __arraycount(x));
}
