+2025-07-28 Paul Eggert <eggert@cs.ucla.edu>
+
+ 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.
+
2025-07-23 Collin Funk <collin.funk1@gmail.com>
posixtm tests: Avoid test failure on Haiku.
# define LDBL_MAX_10_EXP 4932
#endif
-/* On PowerPC with gcc 15 when using __ibm128 long double, the value of
- LDBL_MIN_EXP, LDBL_MIN, LDBL_MAX, and LDBL_NORM_MAX are wrong. */
-#if ((defined _ARCH_PPC || defined _POWER) && LDBL_MANT_DIG == 106 \
- && defined __GNUC__)
+/* On AIX 7.1 with gcc 4.2, the values of LDBL_MIN_EXP, LDBL_MIN, LDBL_MAX are
+ wrong.
+ On Linux/PowerPC with gcc 8.3, the values of LDBL_MAX and LDBL_EPSILON are
+ wrong.
+ Assume these bugs are fixed in any GCC new enough
+ to define __LDBL_NORM_MAX__. */
+#if (defined __powerpc__ && LDBL_MANT_DIG == 106 \
+ && defined __GNUC__ && !defined __LDBL_NORM_MAX__)
# undef LDBL_MIN_EXP
-# define LDBL_MIN_EXP DBL_MIN_EXP
+# define LDBL_MIN_EXP (-968)
# undef LDBL_MIN_10_EXP
-# define LDBL_MIN_10_EXP DBL_MIN_10_EXP
+# define LDBL_MIN_10_EXP (-291)
# undef LDBL_MIN
-# define LDBL_MIN 2.22507385850720138309023271733240406422e-308L /* DBL_MIN = 2^-1022 */
+# define LDBL_MIN 0x1p-969L
+
+/* IBM long double is tricky: it is represented as the sum of two doubles,
+ and the high double must equal the sum of the two parts rounded to nearest.
+ The maximum finite value for which this is true is
+ { 0x1.fffffffffffffp+1023, 0x1.ffffffffffffep+969 },
+ which represents 0x1.fffffffffffff7ffffffffffff8p+1023L.
+ Although computations can yield representations of numbers larger than this,
+ these computations are considered to have overflowed and behavior is undefined.
+ See <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120993>. */
# undef LDBL_MAX
-/* LDBL_MAX is 2**1024 - 2**918, represented as: { 0x7FEFFFFF, 0xFFFFFFFF,
- 0x7C9FFFFF, 0xFFFFFFFF }.
-
- Do not write it as a constant expression, as GCC would likely treat
- that as infinity due to the vagaries of this platform's funky arithmetic.
- Instead, define it through a reference to an external variable.
- Like the following, but using a union to avoid type mismatches:
-
- const double LDBL_MAX[2] = { DBL_MAX, DBL_MAX / 0x1p53 };
- extern const long double LDBL_MAX;
-
- The following alternative would not work as well when GCC is optimizing:
-
- #define LDBL_MAX (*(long double const *) (double[])
- { DBL_MAX, DBL_MAX / 0x1p53 })
-
- The following alternative would require GCC 6 or later:
-
- #define LDBL_MAX __builtin_pack_longdouble (DBL_MAX, DBL_MAX / 0x1p53)
-
- Unfortunately none of the alternatives are constant expressions. */
-# if !GNULIB_defined_long_double_union
-union gl_long_double_union
- {
- struct { double hi; double lo; } dd;
- long double ld;
- };
-# define GNULIB_defined_long_double_union 1
-# endif
-extern const union gl_long_double_union gl_LDBL_MAX;
-# define LDBL_MAX (gl_LDBL_MAX.ld)
-# undef LDBL_NORM_MAX
-# define LDBL_NORM_MAX LDBL_MAX
-#endif
-
-/* On IRIX 6.5, with cc, the value of LDBL_MANT_DIG is wrong.
- On IRIX 6.5, with gcc 4.2, the values of LDBL_MIN_EXP, LDBL_MIN, LDBL_EPSILON
- are wrong. */
-#if defined __sgi && (LDBL_MANT_DIG >= 106)
-# undef LDBL_MANT_DIG
-# define LDBL_MANT_DIG 106
-# if defined __GNUC__
-# undef LDBL_MIN_EXP
-# define LDBL_MIN_EXP DBL_MIN_EXP
-# undef LDBL_MIN_10_EXP
-# define LDBL_MIN_10_EXP DBL_MIN_10_EXP
-# undef LDBL_MIN
-# define LDBL_MIN 2.22507385850720138309023271733240406422e-308L /* DBL_MIN = 2^-1022 */
-# undef LDBL_EPSILON
-# define LDBL_EPSILON 2.46519032881566189191165176650870696773e-32L /* 2^-105 */
-# endif
-#endif
+# define LDBL_MAX 0x1.fffffffffffff7ffffffffffff8p+1023L
/* On PowerPC platforms, 'long double' has a double-double representation.
Up to ISO C 17, this was outside the scope of ISO C because it can represent
numbers with mantissas of the form 1.<52 bits><many zeroes><52 bits> are
called "unnormalized". And since LDBL_EPSILON must be normalized (per
ISO C 23 ยง 5.2.5.3.3.(33)), it must be 2^-105. */
-#if defined __powerpc__ && LDBL_MANT_DIG == 106
# undef LDBL_EPSILON
-# define LDBL_EPSILON 2.46519032881566189191165176650870696773e-32L /* 2^-105 */
+# define LDBL_EPSILON 0x1p-105L
#endif
/* ============================ ISO C11 support ============================ */
#ifndef LDBL_NORM_MAX
# ifdef __LDBL_NORM_MAX__
# define LDBL_NORM_MAX __LDBL_NORM_MAX__
+# elif FLT_RADIX == 2 && LDBL_MAX_EXP == 1024 && LDBL_MANT_DIG == 106
+# define LDBL_NORM_MAX 0x1.ffffffffffffffffffffffffff8p+1022L
# else
# define LDBL_NORM_MAX LDBL_MAX
# endif
ASSERT (LDBL_MAX_10_EXP == (int) (LDBL_MAX_EXP * 0.30103));
/* Check the value of LDBL_MAX. */
- {
- volatile long double m = LDBL_MAX;
- int n;
+ 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));
- }
- }
+ 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. */
{
#endif
/* Check the value of LDBL_NORM_MAX. */
- ASSERT (LDBL_NORM_MAX == normalize_long_double (LDBL_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));
projects / thirdparty / gnulib.git / commitdiff
