float-h: port to C23 PowerPC GCC

* lib/float.in.h (LDBL_MAX) [__LDBL_NORM_MAX__]: Do not override, as
GCC versions defining __LDBL_NORM_MAX__ surely have LDBL_MAX right.
(LDBL_NORM_MAX): Prefer __LDBL_NORM_MAX__ if defined.
Otherwise, hardcode PowerPC value if applicable.
* tests/test-float-h.c (normalize_long_double):
Fix typo that broke this function when given large numbers.
(test_long_double): Normalize LDBL_MAX before comparing it
to LDBL_NORM_MAX.

diff --git a/ChangeLog b/ChangeLog
index df445d4b76d619c909b0269ab4fffcc14f672d0a..998838c98f0bf4ae11c17a69d9ffb37dd682ec3b 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,8 +1,14 @@
 2025-07-06  Paul Eggert  <eggert@cs.ucla.edu>
 
        float-h-tests: port to C23 PowerPC GCC
-       Problem reported by C. Neidhal
-       <https://lists.gnu.org/r/bug-gnulib/2025-07/msg00021.html>.
+       Problems reported by C. Neidhal in:
+       https://lists.gnu.org/r/bug-gnulib/2025-07/msg00021.html
+       https://lists.gnu.org/r/bug-gnulib/2025-07/msg00027.html
+       * lib/float.in.h (LDBL_MAX): Do not override on PowerPC
+       if __LDBL_NORM_MAX__ is defined, as GCC versions defining that
+       symbol surely have LDBL_MAX right.
+       (LDBL_NORM_MAX): Prefer __LDBL_NORM_MAX__ if defined.
+       Otherwise, hardcode PowerPC value if applicable.
        * modules/float-h-tests (Depends-on): Add floorl, frexpl, ldexpl.
        (test_float_h_LDADD): Link the resulting libms too.
        * tests/test-float-h.c: Include math.h.

diff --git a/lib/float.in.h b/lib/float.in.h
index 54093f6e7e0c234fa132531f411442d72041077a..86af55ad1bd09723ff42b22fee7bdd9c5b0ce323 100644 (file)
--- a/lib/float.in.h
+++ b/lib/float.in.h
@@ -124,7 +124,7 @@ extern const union gl_long_double_union gl_LDBL_MAX;
 # undef LDBL_MIN
 # define LDBL_MIN 2.22507385850720138309023271733240406422e-308L /* DBL_MIN = 2^-1022 */
 #endif
-#if (defined _ARCH_PPC || defined _POWER) && (defined _AIX || defined __linux__) && (LDBL_MANT_DIG == 106) && defined __GNUC__
+#if (defined _ARCH_PPC || defined _POWER) && (defined _AIX || defined __linux__) && (LDBL_MANT_DIG == 106) && defined __GNUC__ && !defined __LDBL_NORM_MAX__
 # undef LDBL_MAX
 /* LDBL_MAX is represented as { 0x7FEFFFFF, 0xFFFFFFFF, 0x7C8FFFFF, 0xFFFFFFFF }.
    It is not easy to define:
@@ -309,7 +309,13 @@ extern gl_DBL_SNAN_t gl_DBL_SNAN;
 # endif
 #endif
 #ifndef LDBL_NORM_MAX
-# define LDBL_NORM_MAX LDBL_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 8.98846567431157953864652595394501E+307L
+# else
+#  define LDBL_NORM_MAX LDBL_MAX
+# endif
 #endif
 #ifndef LDBL_SNAN
 /* For sh, beware of <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111814>.  */

diff --git a/tests/test-float-h.c b/tests/test-float-h.c
index c0440bc3f0d0f157b06ead1151642226d97e83d8..1e294c87e090bb407437148a5a7f9b78020b0de0 100644 (file)
--- a/tests/test-float-h.c
+++ b/tests/test-float-h.c
@@ -412,7 +412,7 @@ normalize_long_double (long double volatile x)
     {
       int xexp;
       long double volatile xfrac = frexpl (x, &xexp);
-      x = ldexpl (floorl (ldexpl (xfrac, LDBL_MANT_DIG - xexp)),
+      x = ldexpl (floorl (ldexpl (xfrac, LDBL_MANT_DIG)),
                   xexp - LDBL_MANT_DIG);
     }
   else
@@ -510,7 +510,7 @@ test_long_double (void)
 #endif
 
   /* Check the value of LDBL_NORM_MAX.  */
-  ASSERT (LDBL_NORM_MAX == LDBL_MAX);
+  ASSERT (LDBL_NORM_MAX == normalize_long_double (LDBL_MAX));
 
   /* Check the value of LDBL_SNAN.  */
   ASSERT (isnanl (LDBL_SNAN));