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GNU C Library master sources branch master updated. glibc-2.24-196-gb59ad2d
- From: jsm28 at sourceware dot org
- To: glibc-cvs at sourceware dot org
- Date: 28 Sep 2016 21:12:26 -0000
- Subject: GNU C Library master sources branch master updated. glibc-2.24-196-gb59ad2d
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http://sourceware.org/git/gitweb.cgi?p=glibc.git;a=commitdiff;h=b59ad2db99df74326ae28926299469eecce6f468
commit b59ad2db99df74326ae28926299469eecce6f468
Author: Joseph Myers <joseph@codesourcery.com>
Date: Wed Sep 28 21:11:58 2016 +0000
Fix iszero for excess precision.
Floating-point classification macros are supposed to remove any excess
range or precision from their arguments. This patch fixes the
non-sNaN version of iszero to do so, by casting the argument to its
own type. (This will of course work only for standard-conforming
excess precision, not for what GCC does on 32-bit x86 by default where
the back end hides excess precision from the front end; the same
applies to most of the classification macros in that case, as showed
up when we made them use GCC built-in functions.)
(iseqsig will have the reverse issue, needing to ensure that when an
underlying function is used it's for a type wide enough not to remove
any excess precision, since comparison macros must not remove excess
precision.)
Tested for x86_64 and x86.
* math/math.h
[__GLIBC_USE (IEC_60559_BFP_EXT) && !__SUPPORT_SNAN__] (iszero):
Cast argument to its own type.
* math/test-iszero-excess-precision.c: New file.
* math/Makefile (tests): Add test-iszero-excess-precision.
(CFLAGS-test-iszero-excess-precision.c): New variable.
diff --git a/ChangeLog b/ChangeLog
index 6d6e668..1f9538c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2016-09-28 Joseph Myers <joseph@codesourcery.com>
+
+ * math/math.h
+ [__GLIBC_USE (IEC_60559_BFP_EXT) && !__SUPPORT_SNAN__] (iszero):
+ Cast argument to its own type.
+ * math/test-iszero-excess-precision.c: New file.
+ * math/Makefile (tests): Add test-iszero-excess-precision.
+ (CFLAGS-test-iszero-excess-precision.c): New variable.
+
2016-09-28 Rasmus Villemoes <rv@rasmusvillemoes.dk>
* sysdeps/unix/sysv/linux/spawni.c (posix_spawn_args): Remove pipe
diff --git a/math/Makefile b/math/Makefile
index 6c58b97..7ccd59a 100644
--- a/math/Makefile
+++ b/math/Makefile
@@ -156,7 +156,7 @@ tests = test-matherr test-fenv atest-exp atest-sincos atest-exp2 basic-test \
test-signgam-ullong-init test-nan-overflow test-nan-payload \
test-fexcept test-fexcept-traps test-fesetexcept \
test-fesetexcept-traps test-fetestexceptflag test-femode \
- test-femode-traps $(tests-static)
+ test-femode-traps test-iszero-excess-precision $(tests-static)
tests-static = test-fpucw-static test-fpucw-ieee-static \
test-signgam-uchar-static test-signgam-uchar-init-static \
test-signgam-uint-static test-signgam-uint-init-static \
@@ -266,6 +266,8 @@ CFLAGS-test-signgam-ullong-init-static.c = -std=c99
CFLAGS-test-math-isinff.cc = -std=gnu++11
+CFLAGS-test-iszero-excess-precision.c = -fexcess-precision=standard
+
# The -lieee module sets the _LIB_VERSION_ switch to IEEE mode
# for error handling in the -lm functions.
install-lib += libieee.a
diff --git a/math/math.h b/math/math.h
index 0a09959..1382baa 100644
--- a/math/math.h
+++ b/math/math.h
@@ -336,7 +336,7 @@ enum
# ifdef __SUPPORT_SNAN__
# define iszero(x) (fpclassify (x) == FP_ZERO)
# else
-# define iszero(x) ((x) == 0)
+# define iszero(x) (((__typeof (x)) (x)) == 0)
# endif
#endif /* Use IEC_60559_BFP_EXT. */
diff --git a/math/test-iszero-excess-precision.c b/math/test-iszero-excess-precision.c
new file mode 100644
index 0000000..52abc5a
--- /dev/null
+++ b/math/test-iszero-excess-precision.c
@@ -0,0 +1,49 @@
+/* Test iszero with excess precision.
+ Copyright (C) 2016 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <float.h>
+#include <math.h>
+#include <stdio.h>
+
+#define TEST(TYPE, TRUE_MIN) \
+ do \
+ { \
+ if (iszero (TRUE_MIN / 2)) \
+ puts ("iszero removes excess precision for " #TYPE); \
+ else \
+ { \
+ puts ("iszero fails to remove excess precision for " #TYPE); \
+ result = 1; \
+ } \
+ } \
+ while (0)
+
+static int
+do_test (void)
+{
+ int result = 0;
+
+ TEST (float, FLT_TRUE_MIN);
+ TEST (double, DBL_TRUE_MIN);
+ TEST (long double, LDBL_TRUE_MIN);
+
+ return result;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"
-----------------------------------------------------------------------
Summary of changes:
ChangeLog | 9 ++++
math/Makefile | 4 +-
math/math.h | 2 +-
...{test-powl.c => test-iszero-excess-precision.c} | 44 +++++++++-----------
4 files changed, 33 insertions(+), 26 deletions(-)
copy math/{test-powl.c => test-iszero-excess-precision.c} (64%)
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