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Hash :
1ce8849f
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Date :
2025-07-28T17:50:30
float-h: change IBM long double to match GCC 15 This is in response to the GCC developers; see <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120993>. * lib/float.c (gl_LDBL_MAX): Remove the implementation for PowerPC, as it should no longer be needed. * lib/float.in.h (LDBL_MIN_EXP, LDBL_MIN_10_EXP, LDBL_MIN) (LDBL_MAX, LDBL_EPSILON, LDBL_NORM_MAX): On PowerPC with IBM long double, simplify by using the GCC 15 values unconditionally. These are the correct values according to the GCC developers and there seems little point to disagreeing with current GCC about obsolescent arithmetic that is so problematic in practice. * tests/test-float-h.c (test_long_double): Relax tests of LDBL_MAX when !LDBL_IS_IEC_60559, as the tests would now fail on PowerPC and they were not portable in that case anyway.
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/* Test of <float.h> substitute.
Copyright (C) 2011-2025 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
/* Written by Bruno Haible <bruno@clisp.org>, 2011. */
#include <config.h>
#include <float.h>
/* Check that some macros are constant expressions. */
int a[] =
{
FLT_RADIX,
FLT_EVAL_METHOD /* added in ISO C 99 */
};
/* ----------------------- Check macros for 'float' ----------------------- */
/* Check that the FLT_* macros expand to constant expressions. */
int fb[] =
{
FLT_MANT_DIG, FLT_MIN_EXP, FLT_MAX_EXP,
FLT_DIG, FLT_MIN_10_EXP, FLT_MAX_10_EXP,
FLT_HAS_SUBNORM, /* added in ISO C 11 */
FLT_DECIMAL_DIG, /* added in ISO C 11 */
FLT_IS_IEC_60559 /* added in ISO C 23 */
};
float fc[] =
{
FLT_EPSILON, FLT_MIN, FLT_MAX,
FLT_TRUE_MIN, /* added in ISO C 11 */
FLT_NORM_MAX /* added in ISO C 23 */
};
#if 0 /* FLT_SNAN is not a constant expression on some platforms. */
float fs = FLT_SNAN; /* added in ISO C 23 */
#endif
/* ----------------------- Check macros for 'double' ----------------------- */
/* Check that the DBL_* macros expand to constant expressions. */
int db[] =
{
DBL_MANT_DIG, DBL_MIN_EXP, DBL_MAX_EXP,
DBL_DIG, DBL_MIN_10_EXP, DBL_MAX_10_EXP,
DBL_HAS_SUBNORM, /* added in ISO C 11 */
DBL_DECIMAL_DIG, /* added in ISO C 11 */
DBL_IS_IEC_60559 /* added in ISO C 23 */
};
double dc[] =
{
DBL_EPSILON, DBL_MIN, DBL_MAX,
DBL_TRUE_MIN, /* added in ISO C 11 */
DBL_NORM_MAX /* added in ISO C 23 */
};
#if 0 /* DBL_SNAN is not a constant expression on some platforms. */
double ds = DBL_SNAN; /* added in ISO C 23 */
#endif
/* -------------------- Check macros for 'long double' -------------------- */
/* Check that the LDBL_* macros expand to constant expressions. */
int lb[] =
{
LDBL_MANT_DIG, LDBL_MIN_EXP, LDBL_MAX_EXP,
LDBL_DIG, LDBL_MIN_10_EXP, LDBL_MAX_10_EXP,
LDBL_HAS_SUBNORM, /* added in ISO C 11 */
LDBL_DECIMAL_DIG, /* added in ISO C 11 */
LDBL_IS_IEC_60559 /* added in ISO C 23 */
};
long double lc1 = LDBL_EPSILON;
long double lc2 = LDBL_MIN;
#if !GNULIB_defined_long_double_union
/* LDBL_MAX is not a constant expression on some platforms. */
long double lc3 = LDBL_MAX;
#endif
#if !GNULIB_defined_long_double_union
/* LDBL_TRUE_MIN is not a constant expression on FreeBSD/i386. */
long double lc4 = LDBL_TRUE_MIN; /* added in ISO C 11 */
#endif
#if !GNULIB_defined_long_double_union
/* LDBL_MAX is not a constant expression on some platforms. */
long double lc5 = LDBL_NORM_MAX; /* added in ISO C 23 */
#endif
#if 0
/* LDBL_SNAN is not a constant expression on some platforms. */
long double ls = LDBL_SNAN; /* added in ISO C 23 */
#endif
/* ------------------------------------------------------------------------- */
#include <math.h>
#include "fpucw.h"
#include "isnanf-nolibm.h"
#include "isnand-nolibm.h"
#include "isnanl-nolibm.h"
#include "macros.h"
#if FLT_RADIX == 2
/* Return 2^n. */
static float
pow2f (int n)
{
int k = n;
volatile float x = 1;
volatile float y = 2;
/* Invariant: 2^n == x * y^k. */
if (k < 0)
{
y = 0.5f;
k = - k;
}
while (k > 0)
{
if (k != 2 * (k / 2))
{
x = x * y;
k = k - 1;
}
if (k == 0)
break;
y = y * y;
k = k / 2;
}
/* Now k == 0, hence x == 2^n. */
return x;
}
/* Return 2^n. */
static double
pow2d (int n)
{
int k = n;
volatile double x = 1;
volatile double y = 2;
/* Invariant: 2^n == x * y^k. */
if (k < 0)
{
y = 0.5;
k = - k;
}
while (k > 0)
{
if (k != 2 * (k / 2))
{
x = x * y;
k = k - 1;
}
if (k == 0)
break;
y = y * y;
k = k / 2;
}
/* Now k == 0, hence x == 2^n. */
return x;
}
/* Return 2^n. */
static long double
pow2l (int n)
{
int k = n;
volatile long double x = 1;
volatile long double y = 2;
/* Invariant: 2^n == x * y^k. */
if (k < 0)
{
y = 0.5L;
k = - k;
}
while (k > 0)
{
if (k != 2 * (k / 2))
{
x = x * y;
k = k - 1;
}
if (k == 0)
break;
y = y * y;
k = k / 2;
}
/* Now k == 0, hence x == 2^n. */
return x;
}
/* ----------------------- Check macros for 'float' ----------------------- */
static void
test_float (void)
{
/* Check that the value of FLT_MIN_EXP is well parenthesized. */
ASSERT ((FLT_MIN_EXP % 101111) == (FLT_MIN_EXP) % 101111);
/* Check that the value of DBL_MIN_10_EXP is well parenthesized. */
ASSERT ((FLT_MIN_10_EXP % 101111) == (FLT_MIN_10_EXP) % 101111);
/* Check that 'float' is as specified in IEEE 754. */
ASSERT (FLT_MANT_DIG == 24);
ASSERT (FLT_MIN_EXP == -125);
ASSERT (FLT_MAX_EXP == 128);
/* Check the value of FLT_MIN_10_EXP. */
ASSERT (FLT_MIN_10_EXP == - (int) (- (FLT_MIN_EXP - 1) * 0.30103));
/* Check the value of FLT_DIG. */
ASSERT (FLT_DIG == (int) ((FLT_MANT_DIG - 1) * 0.30103));
/* Check the value of FLT_MIN_10_EXP. */
ASSERT (FLT_MIN_10_EXP == - (int) (- (FLT_MIN_EXP - 1) * 0.30103));
/* Check the value of FLT_MAX_10_EXP. */
ASSERT (FLT_MAX_10_EXP == (int) (FLT_MAX_EXP * 0.30103));
/* Check the value of FLT_MAX. */
{
volatile float m = FLT_MAX;
int n;
ASSERT (m + m > m);
for (n = 0; n <= 2 * FLT_MANT_DIG; n++)
{
volatile float pow2_n = pow2f (n); /* 2^n */
volatile float x = m + (m / pow2_n);
if (x > m)
ASSERT (x + x == x);
else
ASSERT (!(x + x == x));
}
}
/* Check the value of FLT_MIN. */
{
volatile float m = FLT_MIN;
volatile float x = pow2f (FLT_MIN_EXP - 1);
ASSERT (m == x);
}
/* Check the value of FLT_EPSILON. */
{
volatile float e = FLT_EPSILON;
volatile float me;
int n;
me = 1.0f + e;
ASSERT (me > 1.0f);
ASSERT (me - 1.0f == e);
for (n = 0; n <= 2 * FLT_MANT_DIG; n++)
{
volatile float half_n = pow2f (- n); /* 2^-n */
volatile float x = me - half_n;
if (x < me)
ASSERT (x <= 1.0f);
}
}
/* Check the value of FLT_HAS_SUBNORM. */
ASSERT (FLT_HAS_SUBNORM == 1);
/* Check the value of FLT_DECIMAL_DIG. */
ASSERT (FLT_DECIMAL_DIG == (int)(FLT_MANT_DIG * 0.3010299956639812 + 2));
/* Check the value of FLT_TRUE_MIN. */
ASSERT (FLT_TRUE_MIN > 0.0f);
{
volatile float x = FLT_TRUE_MIN * 0.5f;
ASSERT (x == 0.0f);
}
/* Check the value of FLT_IS_IEC_60559. */
#if !defined __m68k__
ASSERT (FLT_IS_IEC_60559);
#elif 0
/* It is not clear what this macro actually means. Cf.
<https://mailman.oakapple.net/pipermail/cfp-interest/2023-April/002760.html> */
ASSERT (!FLT_IS_IEC_60559);
#endif
/* Check the value of FLT_NORM_MAX. */
ASSERT (FLT_NORM_MAX == FLT_MAX);
/* Check the value of FLT_SNAN. */
ASSERT (isnanf (FLT_SNAN));
}
/* ----------------------- Check macros for 'double' ----------------------- */
static void
test_double (void)
{
/* Check that the value of DBL_MIN_EXP is well parenthesized. */
ASSERT ((DBL_MIN_EXP % 101111) == (DBL_MIN_EXP) % 101111);
/* Check that the value of DBL_MIN_10_EXP is well parenthesized. */
ASSERT ((DBL_MIN_10_EXP % 101111) == (DBL_MIN_10_EXP) % 101111);
/* Check that 'double' is as specified in IEEE 754. */
ASSERT (DBL_MANT_DIG == 53);
ASSERT (DBL_MIN_EXP == -1021);
ASSERT (DBL_MAX_EXP == 1024);
/* Check the value of DBL_MIN_10_EXP. */
ASSERT (DBL_MIN_10_EXP == - (int) (- (DBL_MIN_EXP - 1) * 0.30103));
/* Check the value of DBL_DIG. */
ASSERT (DBL_DIG == (int) ((DBL_MANT_DIG - 1) * 0.30103));
/* Check the value of DBL_MIN_10_EXP. */
ASSERT (DBL_MIN_10_EXP == - (int) (- (DBL_MIN_EXP - 1) * 0.30103));
/* Check the value of DBL_MAX_10_EXP. */
ASSERT (DBL_MAX_10_EXP == (int) (DBL_MAX_EXP * 0.30103));
/* Check the value of DBL_MAX. */
{
volatile double m = DBL_MAX;
int n;
ASSERT (m + m > m);
for (n = 0; n <= 2 * DBL_MANT_DIG; n++)
{
volatile double pow2_n = pow2d (n); /* 2^n */
volatile double x = m + (m / pow2_n);
if (x > m)
ASSERT (x + x == x);
else
ASSERT (!(x + x == x));
}
}
/* Check the value of DBL_MIN. */
{
volatile double m = DBL_MIN;
volatile double x = pow2d (DBL_MIN_EXP - 1);
ASSERT (m == x);
}
/* Check the value of DBL_EPSILON. */
{
volatile double e = DBL_EPSILON;
volatile double me;
int n;
me = 1.0 + e;
ASSERT (me > 1.0);
ASSERT (me - 1.0 == e);
for (n = 0; n <= 2 * DBL_MANT_DIG; n++)
{
volatile double half_n = pow2d (- n); /* 2^-n */
volatile double x = me - half_n;
if (x < me)
ASSERT (x <= 1.0);
}
}
/* Check the value of DBL_HAS_SUBNORM. */
ASSERT (DBL_HAS_SUBNORM == 1);
/* Check the value of DBL_DECIMAL_DIG. */
ASSERT (DBL_DECIMAL_DIG == (int)(DBL_MANT_DIG * 0.3010299956639812 + 2));
/* Check the value of DBL_TRUE_MIN. */
ASSERT (DBL_TRUE_MIN > 0.0);
{
volatile double x = DBL_TRUE_MIN * 0.5;
ASSERT (x == 0.0);
}
/* Check the value of DBL_IS_IEC_60559. */
#if !defined __m68k__
ASSERT (DBL_IS_IEC_60559);
#elif 0
/* It is not clear what this macro actually means. Cf.
<https://mailman.oakapple.net/pipermail/cfp-interest/2023-April/002760.html> */
ASSERT (!DBL_IS_IEC_60559);
#endif
/* Check the value of DBL_NORM_MAX. */
ASSERT (DBL_NORM_MAX == DBL_MAX);
/* Check the value of DBL_SNAN. */
ASSERT (isnand (DBL_SNAN));
}
/* -------------------- Check macros for 'long double' -------------------- */
static int
test_isfinitel (long double volatile x)
{
if (x != x)
return 0;
long double volatile zero = x * 0;
return zero == 0;
}
/* Return X after normalization. This makes a difference on platforms
where long double can represent unnormalized values. For example,
suppose x = 1 + 2**-106 on PowerPC with IBM long double where
FLT_RADIX = 2, LDBL_MANT_DIG = 106, and LDBL_EPSILON = 2**-105.
Then 1 < x < 1 + LDBL_EPSILON, and normalize_long_double (x) returns 1. */
static long double
normalize_long_double (long double volatile x)
{
if (FLT_RADIX == 2 && test_isfinitel (x))
{
int xexp;
long double volatile
frac = frexpl (x, &xexp),
significand = frac * pow2l (LDBL_MANT_DIG),
normalized_significand = truncl (significand),
normalized_x = normalized_significand * pow2l (xexp - LDBL_MANT_DIG);
/* The test_isfinitel defends against PowerPC with IBM long double,
which fritzes out near LDBL_MAX. */
if (test_isfinitel (normalized_x))
x = normalized_x;
}
else
{
/* Hope that X is already normalized. */
}
return x;
}
static void
test_long_double (void)
{
/* Check that the value of LDBL_MIN_EXP is well parenthesized. */
ASSERT ((LDBL_MIN_EXP % 101111) == (LDBL_MIN_EXP) % 101111);
/* Check that the value of LDBL_MIN_10_EXP is well parenthesized. */
ASSERT ((LDBL_MIN_10_EXP % 101111) == (LDBL_MIN_10_EXP) % 101111);
/* Check that 'long double' is at least as wide as 'double'. */
ASSERT (LDBL_MANT_DIG >= DBL_MANT_DIG);
ASSERT (LDBL_MIN_EXP - LDBL_MANT_DIG <= DBL_MIN_EXP - DBL_MANT_DIG);
ASSERT (LDBL_MAX_EXP >= DBL_MAX_EXP);
/* Check the value of LDBL_DIG. */
ASSERT (LDBL_DIG == (int)((LDBL_MANT_DIG - 1) * 0.30103));
/* Check the value of LDBL_MIN_10_EXP. */
ASSERT (LDBL_MIN_10_EXP == - (int) (- (LDBL_MIN_EXP - 1) * 0.30103));
/* Check the value of LDBL_MAX_10_EXP. */
ASSERT (LDBL_MAX_10_EXP == (int) (LDBL_MAX_EXP * 0.30103));
/* Check the value of LDBL_MAX. */
if (LDBL_IS_IEC_60559)
{
volatile long double m = LDBL_MAX;
int n;
ASSERT (m + m > m);
for (n = 0; n <= 2 * LDBL_MANT_DIG; n++)
{
volatile long double pow2_n = pow2l (n); /* 2^n */
volatile long double x = m + (m / pow2_n);
if (x > m)
ASSERT (x + x == x);
else
ASSERT (!(x + x == x));
}
}
/* Check the value of LDBL_MIN. */
{
volatile long double m = LDBL_MIN;
volatile long double x = pow2l (LDBL_MIN_EXP - 1);
ASSERT (m == x);
}
/* Check the value of LDBL_EPSILON. */
{
volatile long double e = LDBL_EPSILON;
volatile long double me;
int n;
me = 1.0L + e;
ASSERT (me > 1.0L);
ASSERT (me - 1.0L == e);
for (n = 0; n <= 2 * LDBL_MANT_DIG; n++)
{
volatile long double half_n = pow2l (- n); /* 2^-n */
volatile long double x = normalize_long_double (me - half_n);
if (x < me)
ASSERT (x <= 1.0L);
}
}
/* Check the value of LDBL_HAS_SUBNORM. */
ASSERT (LDBL_HAS_SUBNORM == 1);
/* Check the value of LDBL_DECIMAL_DIG. */
ASSERT (LDBL_DECIMAL_DIG == (int)(LDBL_MANT_DIG * 0.3010299956639812 + 2));
/* Check the value of LDBL_TRUE_MIN. */
ASSERT (LDBL_TRUE_MIN > 0.0L);
{
volatile long double x = LDBL_TRUE_MIN * 0.5L;
ASSERT (x == 0.0L);
}
/* Check the value of LDBL_IS_IEC_60559. */
#if (LDBL_MANT_DIG == 53 || LDBL_MANT_DIG == 113) && !defined __m68k__
ASSERT (LDBL_IS_IEC_60559);
#elif 0
/* It is not clear what this macro actually means. Cf.
<https://mailman.oakapple.net/pipermail/cfp-interest/2023-April/002760.html> */
ASSERT (!LDBL_IS_IEC_60559);
#endif
/* Check the value of LDBL_NORM_MAX. */
if (LDBL_IS_IEC_60559)
ASSERT (LDBL_NORM_MAX == normalize_long_double (LDBL_MAX));
/* Check the value of LDBL_SNAN. */
ASSERT (isnanl (LDBL_SNAN));
}
int
main ()
{
test_float ();
test_double ();
{
DECL_LONG_DOUBLE_ROUNDING
BEGIN_LONG_DOUBLE_ROUNDING ();
test_long_double ();
END_LONG_DOUBLE_ROUNDING ();
}
return test_exit_status;
}
#else
int
main ()
{
fprintf (stderr, "Skipping test: FLT_RADIX is not 2.\n");
return 77;
}
#endif