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b59ad2db99
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.
50 lines
1.4 KiB
C
50 lines
1.4 KiB
C
/* Test iszero with excess precision.
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Copyright (C) 2016 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <float.h>
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#include <math.h>
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#include <stdio.h>
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#define TEST(TYPE, TRUE_MIN) \
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do \
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{ \
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if (iszero (TRUE_MIN / 2)) \
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puts ("iszero removes excess precision for " #TYPE); \
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else \
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{ \
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puts ("iszero fails to remove excess precision for " #TYPE); \
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result = 1; \
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} \
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} \
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while (0)
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static int
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do_test (void)
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{
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int result = 0;
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TEST (float, FLT_TRUE_MIN);
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TEST (double, DBL_TRUE_MIN);
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TEST (long double, LDBL_TRUE_MIN);
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return result;
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}
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#define TEST_FUNCTION do_test ()
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#include "../test-skeleton.c"
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