[src/trunk]: src/tests/lib/libm The compiler is allowed to use intermediate h...

[mlelstv <mlelstv%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/ef0bd5196549
branches:  trunk
changeset: 771313:ef0bd5196549
user:      mlelstv <mlelstv%NetBSD.org@localhost>
date:      Sat Nov 19 12:46:41 2011 +0000

description:
The compiler is allowed to use intermediate higher precision for float
arithmetic, which may cause differences smaller than float precision
but still much larger than eps = 1e-30.
Forcing intermediate results to volatile variables removes the excess
precision.

diffstat:

 tests/lib/libm/t_sqrt.c |  8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diffs (36 lines):

diff -r a27eb582ccd1 -r ef0bd5196549 tests/lib/libm/t_sqrt.c
--- a/tests/lib/libm/t_sqrt.c   Sat Nov 19 12:32:54 2011 +0000
+++ b/tests/lib/libm/t_sqrt.c   Sat Nov 19 12:46:41 2011 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: t_sqrt.c,v 1.1 2011/10/16 08:25:40 jruoho Exp $ */
+/* $NetBSD: t_sqrt.c,v 1.2 2011/11/19 12:46:41 mlelstv Exp $ */
 
 /*-
  * Copyright (c) 2011 The NetBSD Foundation, Inc.
@@ -29,7 +29,7 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 #include <sys/cdefs.h>
-__RCSID("$NetBSD: t_sqrt.c,v 1.1 2011/10/16 08:25:40 jruoho Exp $");
+__RCSID("$NetBSD: t_sqrt.c,v 1.2 2011/11/19 12:46:41 mlelstv Exp $");
 
 #include <atf-c.h>
 #include <math.h>
@@ -177,7 +177,7 @@
 #ifndef __vax__
        const float x[] = { 0.0, 0.005, 1.0, 99.0, 123.123, 9999.9999 };
        const float eps = 1.0e-30;
-       float y, z;
+       volatile float y, z;
        size_t i;
 
        for (i = 0; i < __arraycount(x); i++) {
@@ -187,7 +187,7 @@
 
                if (fabsf(y - z) > eps)
                        atf_tc_fail_nonfatal("sqrtf(%0.03f) != "
-                           "powf(%0.03f, 1/3)\n", x[i], x[i]);
+                           "powf(%0.03f, 1/2)\n", x[i], x[i]);
        }
 #endif
 }