[patch 4/4] Add isnan module.

[Ben Pfaff]

commit 7900deb696d0fa9c218785a11e141e4aaf64ac80
Author: Ben Pfaff <address@hidden>
Date:   Thu Jul 10 22:15:36 2008 -0700

    Add isnan module.

diff --git a/ChangeLog b/ChangeLog
index eb11c25..fb9b022 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,26 @@
 2008-07-10  Ben Pfaff  <address@hidden>
 
+       Add isnan module.
+        * doc/posix-functions/isnan.texi: Mention new module.
+        * lib/math.in.h: Define isnan macro if we have decided to replace
+        it.
+        * m4/isnan.m4: New file.
+       * m4/isnanl.m4 (gl_FUNC_ISNANL): Factor out some code into new
+       macro gl_BUILD_ISNANL so that isnan.m4 can use that functionality
+       also.
+       (gl_FUNC_ISNANL_NO_LIBM): Factor out same code, to reduce
+       redundancy.
+       * m4/math_h.m4: Initialize and substitute variables for isnan
+       module.
+       * modules/isnan: New file.
+       * modules/isnan-tests: New file.
+       * modules/math: Add substitutions for new module.
+       * tests/test-isnan.c: New file.
+       * MODULES.html.sh: Mention new module.
+       * doc/glibc-function
+
+2008-07-10  Ben Pfaff  <address@hidden>
+
        Add isnanf module.
        * lib/isnanf.m4: New file.
        * m4/isnanf.m4 (gl_FUNC_ISNANF): New macro.
diff --git a/MODULES.html.sh b/MODULES.html.sh
index 58a19d5..8108e3f 100755
--- a/MODULES.html.sh
+++ b/MODULES.html.sh
@@ -1999,6 +1999,7 @@ func_all_modules ()
   func_module frexpl
   func_module frexpl-nolibm
   func_module isfinite
+  func_module isnan
   func_module isnanf
   func_module isnanf-nolibm
   func_module isnand
diff --git a/doc/posix-functions/isnan.texi b/doc/posix-functions/isnan.texi
index 90395c7..0181686 100644
--- a/doc/posix-functions/isnan.texi
+++ b/doc/posix-functions/isnan.texi
@@ -4,10 +4,24 @@
 
 POSIX specification: @url{http://www.opengroup.org/susv3xsh/isnan.html}
 
-Gnulib module: ---
+Gnulib module: isnan
 
 Portability problems fixed by Gnulib:
 @itemize
address@hidden
address@hidden was introduced with C99 and is thus commonly not present
+on pre-C99 systems.
address@hidden
+On IRIX 6.5 with @code{cc}, @code{isnan} does not recognize some NaNs.
address@hidden
+On NetBSD/i386 and glibc/ia64, @code{isnan} does not recognize some
+forms of NaNs, such as pseudo-NaNs, pseudo-Infinities, and
+unnormalized numbers.
address@hidden
+On i686 and @var{x}86-64, @code{__builtin_isnanl} (and thus
address@hidden implementations based on it) in GCC 4.0 and later does
+not recognize pseudo-denormals as NaNs, and similarly for
+pseudo-zeroes, unnormalized numbers, and pseudo-denormals on ia64.
 @end itemize
 
 Portability problems not fixed by Gnulib:
diff --git a/lib/math.in.h b/lib/math.in.h
index f500824..85f3785 100644
--- a/lib/math.in.h
+++ b/lib/math.in.h
@@ -381,6 +381,41 @@ extern int gl_isfinitel (long double x);
 #endif
 
 
+#if @GNULIB_ISNAN@
+# if @REPLACE_ISNAN@
+/* We can't just use the isnanf macro (e.g.) as exposed by
+   isnanf.h (e.g.) here, because those may end up being macros
+   that recursively expand back to isnan.  So use the gnulib
+   replacements for them directly. */
+#  if HAVE_ISNANF && __GNUC__ >= 4
+#   define gl_isnan_f(x) __builtin_isnan ((float)(x))
+#  else
+extern int rpl_isnanf (float x);
+#   define gl_isnan_f(x) rpl_isnanf (x)
+#  endif
+#  if HAVE_ISNAND && __GNUC__ >= 4
+#   define gl_isnan_d(x) __builtin_isnan ((double)(x))
+#  else
+extern int rpl_isnand (double x);
+#   define gl_isnan_d(x) rpl_isnand (x)
+#  endif
+#  if HAVE_ISNANL && __GNUC__ >= 4
+#   define gl_isnan_l(x) __builtin_isnan ((long double)(x))
+#  else
+extern int rpl_isnanl (long double x);
+#   define gl_isnan_l(x) rpl_isnanl (x)
+#  endif
+#  undef isnan
+#  define isnan(x) \
+   (sizeof (x) == sizeof (long double) ? gl_isnan_l (x) : \
+    sizeof (x) == sizeof (double) ? gl_isnan_d (x) : \
+    gl_isnan_f (x))
+# endif
+#elif defined GNULIB_POSIXCHECK
+  /* How to override a macro?  */
+#endif
+
+
 #if @GNULIB_SIGNBIT@
 # if @REPLACE_SIGNBIT_USING_GCC@
 #  undef signbit
diff --git a/m4/isnan.m4 b/m4/isnan.m4
new file mode 100644
index 0000000..fb28c64
--- /dev/null
+++ b/m4/isnan.m4
@@ -0,0 +1,31 @@
+# isnan.m4 serial 1
+dnl Copyright (C) 2007-2008 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_ISNAN],
+[
+  AC_REQUIRE([gl_FUNC_ISNANF])
+  AC_REQUIRE([gl_FUNC_ISNAND])
+  AC_REQUIRE([gl_FUNC_ISNANL])
+
+  ISNAN_LIBM="$ISNANF_LIBM $ISNAND_LIBM $ISNANL_LIBM"
+  AC_SUBST([ISNAN_LIBM])
+
+  # If we replaced any of the underlying isnan* functions, replace
+  # the isnan macro; it undoubtedly suffers from the same flaws.
+  AC_MSG_CHECKING([whether isnan macro works])
+  if test $gl_func_isnanf = yes \
+     && test $gl_func_isnand = yes \
+     && test $gl_func_isnanl = yes; then
+    AC_MSG_RESULT([yes])
+  else
+    # Make sure the rpl_isnan[fdl] functions get built.
+    gl_BUILD_ISNANF
+    gl_BUILD_ISNAND
+    gl_BUILD_ISNANL
+    REPLACE_ISNAN=1
+    AC_MSG_RESULT([no])
+  fi
+])
diff --git a/m4/isnanl.m4 b/m4/isnanl.m4
index 660a898..4c26326 100644
--- a/m4/isnanl.m4
+++ b/m4/isnanl.m4
@@ -31,8 +31,7 @@ AC_DEFUN([gl_FUNC_ISNANL],
     AC_DEFINE([HAVE_ISNANL], 1,
       [Define if the isnan(long double) function is available.])
   else
-    AC_LIBOBJ([isnanl])
-    gl_LONG_DOUBLE_EXPONENT_LOCATION
+    gl_BUILD_ISNANL
   fi
   AC_SUBST([ISNANL_LIBM])
 ])
@@ -52,9 +51,15 @@ AC_DEFUN([gl_FUNC_ISNANL_NO_LIBM],
     AC_DEFINE([HAVE_ISNANL_IN_LIBC], 1,
       [Define if the isnan(long double) function is available in libc.])
   else
+    gl_BUILD_ISNANL
+  fi
+])
+
+dnl Pull in replacement isnanl definition.
+AC_DEFUN([gl_BUILD_ISNANL],
+[
     AC_LIBOBJ([isnanl])
     gl_LONG_DOUBLE_EXPONENT_LOCATION
-  fi
 ])
 
 dnl Test whether isnanl() can be used without libm.
diff --git a/m4/math_h.m4 b/m4/math_h.m4
index 902fdb5..0348f24 100644
--- a/m4/math_h.m4
+++ b/m4/math_h.m4
@@ -51,6 +51,7 @@ AC_DEFUN([gl_MATH_H_DEFAULTS],
   GNULIB_FREXP=0;    AC_SUBST([GNULIB_FREXP])
   GNULIB_FREXPL=0;   AC_SUBST([GNULIB_FREXPL])
   GNULIB_ISFINITE=0; AC_SUBST([GNULIB_ISFINITE])
+  GNULIB_ISNAN=0;    AC_SUBST([GNULIB_ISNAN])
   GNULIB_LDEXPL=0;   AC_SUBST([GNULIB_LDEXPL])
   GNULIB_MATHL=0;    AC_SUBST([GNULIB_MATHL])
   GNULIB_ROUND=0;    AC_SUBST([GNULIB_ROUND])
@@ -82,6 +83,7 @@ AC_DEFUN([gl_MATH_H_DEFAULTS],
   REPLACE_FREXPL=0;            AC_SUBST([REPLACE_FREXPL])
   REPLACE_HUGE_VAL=0;          AC_SUBST([REPLACE_HUGE_VAL])
   REPLACE_ISFINITE=0;          AC_SUBST([REPLACE_ISFINITE])
+  REPLACE_ISNAN=0;             AC_SUBST([REPLACE_ISNAN])
   REPLACE_LDEXPL=0;            AC_SUBST([REPLACE_LDEXPL])
   REPLACE_NAN=0;               AC_SUBST([REPLACE_NAN])
   REPLACE_ROUND=0;             AC_SUBST([REPLACE_ROUND])
diff --git a/modules/isnan b/modules/isnan
new file mode 100644
index 0000000..16972fa
--- /dev/null
+++ b/modules/isnan
@@ -0,0 +1,27 @@
+Description:
+isnan macro: test for NaN value.
+
+Files:
+m4/isnan.m4
+
+Depends-on:
+isnanf
+isnand
+isnanl
+math
+extensions
+
+configure.ac:
+gl_ISNAN
+gl_MATH_MODULE_INDICATOR([isnan])
+
+Makefile.am:
+
+Include:
+<math.h>
+
+License:
+GPL
+
+Maintainer:
+Ben Pfaff
diff --git a/modules/isnan-tests b/modules/isnan-tests
new file mode 100644
index 0000000..f06a783
--- /dev/null
+++ b/modules/isnan-tests
@@ -0,0 +1,16 @@
+Files:
+tests/test-isnan.c
+tests/nan.h
+
+Depends-on:
+
+configure.ac:
+gl_FLOAT_EXPONENT_LOCATION
+gl_DOUBLE_EXPONENT_LOCATION
+gl_LONG_DOUBLE_EXPONENT_LOCATION
+
+Makefile.am:
+TESTS += test-isnan
+check_PROGRAMS += test-isnan
+test_isnan_LDADD = $(LDADD) @ISNAN_LIBM@
+
diff --git a/modules/math b/modules/math
index f3a38da..4be8501 100644
--- a/modules/math
+++ b/modules/math
@@ -29,6 +29,7 @@ math.h: math.in.h
              -e 's|@''GNULIB_FREXP''@|$(GNULIB_FREXP)|g' \
              -e 's|@''GNULIB_FREXPL''@|$(GNULIB_FREXPL)|g' \
              -e 's|@''GNULIB_ISFINITE''@|$(GNULIB_ISFINITE)|g' \
+             -e 's|@''GNULIB_ISNAN''@|$(GNULIB_ISNAN)|g' \
              -e 's|@''GNULIB_LDEXPL''@|$(GNULIB_LDEXPL)|g' \
              -e 's|@''GNULIB_MATHL''@|$(GNULIB_MATHL)|g' \
              -e 's|@''GNULIB_ROUND''@|$(GNULIB_ROUND)|g' \
@@ -59,6 +60,7 @@ math.h: math.in.h
              -e 's|@''REPLACE_FREXPL''@|$(REPLACE_FREXPL)|g' \
              -e 's|@''REPLACE_HUGE_VAL''@|$(REPLACE_HUGE_VAL)|g' \
              -e 's|@''REPLACE_ISFINITE''@|$(REPLACE_ISFINITE)|g' \
+             -e 's|@''REPLACE_ISNAN''@|$(REPLACE_ISNAN)|g' \
              -e 's|@''REPLACE_LDEXPL''@|$(REPLACE_LDEXPL)|g' \
              -e 's|@''REPLACE_NAN''@|$(REPLACE_NAN)|g' \
              -e 's|@''REPLACE_ROUND''@|$(REPLACE_ROUND)|g' \
diff --git a/tests/test-isnan.c b/tests/test-isnan.c
new file mode 100644
index 0000000..9761ee6
--- /dev/null
+++ b/tests/test-isnan.c
@@ -0,0 +1,228 @@
+/* Test of isnand() substitute.
+   Copyright (C) 2007-2008 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 <http://www.gnu.org/licenses/>.  */
+
+/* Written by Ben Pfaff <address@hidden>, from code by Bruno
+   Haible <address@hidden>.  */
+
+#include <config.h>
+
+#include <math.h>
+
+#include <float.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "nan.h"
+
+#define ASSERT(expr) \
+  do                                                                        \
+    {                                                                       \
+      if (!(expr))                                                          \
+        {                                                                   \
+          fprintf (stderr, "%s:%d: assertion failed\n", __FILE__, __LINE__); \
+          fflush (stderr);                                                  \
+          abort ();                                                         \
+        }                                                                   \
+    }                                                                       \
+  while (0)
+
+static void
+test_float (void)
+{
+  /* Finite values.  */
+  ASSERT (!isnan (3.141f));
+  ASSERT (!isnan (3.141e30f));
+  ASSERT (!isnan (3.141e-30f));
+  ASSERT (!isnan (-2.718f));
+  ASSERT (!isnan (-2.718e30f));
+  ASSERT (!isnan (-2.718e-30f));
+  ASSERT (!isnan (0.0f));
+  ASSERT (!isnan (-0.0f));
+  /* Infinite values.  */
+  ASSERT (!isnan (1.0f / 0.0f));
+  ASSERT (!isnan (-1.0f / 0.0f));
+  /* Quiet NaN.  */
+  ASSERT (isnan (NaNf ()));
+#if defined FLT_EXPBIT0_WORD && defined FLT_EXPBIT0_BIT
+  /* Signalling NaN.  */
+  {
+    #define NWORDSF \
+      ((sizeof (float) + sizeof (unsigned int) - 1) / sizeof (unsigned int))
+    typedef union { float value; unsigned int word[NWORDSF]; } memory_float;
+    memory_float m;
+    m.value = NaNf ();
+# if FLT_EXPBIT0_BIT > 0
+    m.word[FLT_EXPBIT0_WORD] ^= (unsigned int) 1 << (FLT_EXPBIT0_BIT - 1);
+# else
+    m.word[FLT_EXPBIT0_WORD + (FLT_EXPBIT0_WORD < NWORDSF / 2 ? 1 : - 1)]
+      ^= (unsigned int) 1 << (sizeof (unsigned int) * CHAR_BIT - 1);
+# endif
+    if (FLT_EXPBIT0_WORD < NWORDSF / 2)
+      m.word[FLT_EXPBIT0_WORD + 1] |= (unsigned int) 1 << FLT_EXPBIT0_BIT;
+    else
+      m.word[0] |= (unsigned int) 1;
+    ASSERT (isnan (m.value));
+  }
+#endif
+}
+
+static void
+test_double (void)
+{
+  /* Finite values.  */
+  ASSERT (!isnan (3.141));
+  ASSERT (!isnan (3.141e30));
+  ASSERT (!isnan (3.141e-30));
+  ASSERT (!isnan (-2.718));
+  ASSERT (!isnan (-2.718e30));
+  ASSERT (!isnan (-2.718e-30));
+  ASSERT (!isnan (0.0));
+  ASSERT (!isnan (-0.0));
+  /* Infinite values.  */
+  ASSERT (!isnan (1.0 / 0.0));
+  ASSERT (!isnan (-1.0 / 0.0));
+  /* Quiet NaN.  */
+  ASSERT (isnan (NaNd ()));
+#if defined DBL_EXPBIT0_WORD && defined DBL_EXPBIT0_BIT
+  /* Signalling NaN.  */
+  {
+    #define NWORDSD \
+      ((sizeof (double) + sizeof (unsigned int) - 1) / sizeof (unsigned int))
+    typedef union { double value; unsigned int word[NWORDSD]; } memory_double;
+    memory_double m;
+    m.value = NaNd ();
+# if DBL_EXPBIT0_BIT > 0
+    m.word[DBL_EXPBIT0_WORD] ^= (unsigned int) 1 << (DBL_EXPBIT0_BIT - 1);
+# else
+    m.word[DBL_EXPBIT0_WORD + (DBL_EXPBIT0_WORD < NWORDSD / 2 ? 1 : - 1)]
+      ^= (unsigned int) 1 << (sizeof (unsigned int) * CHAR_BIT - 1);
+# endif
+    m.word[DBL_EXPBIT0_WORD + (DBL_EXPBIT0_WORD < NWORDSD / 2 ? 1 : - 1)]
+      |= (unsigned int) 1 << DBL_EXPBIT0_BIT;
+    ASSERT (isnan (m.value));
+  }
+#endif
+}
+
+static void
+test_long_double (void)
+{
+  #define NWORDSL \
+    ((sizeof (long double) + sizeof (unsigned int) - 1) / sizeof (unsigned 
int))
+  typedef union { unsigned int word[NWORDSL]; long double value; }
+          memory_long_double;
+
+  /* Finite values.  */
+  ASSERT (!isnan (3.141L));
+  ASSERT (!isnan (3.141e30L));
+  ASSERT (!isnan (3.141e-30L));
+  ASSERT (!isnan (-2.718L));
+  ASSERT (!isnan (-2.718e30L));
+  ASSERT (!isnan (-2.718e-30L));
+  ASSERT (!isnan (0.0L));
+  ASSERT (!isnan (-0.0L));
+  /* Infinite values.  */
+  ASSERT (!isnan (1.0L / 0.0L));
+  ASSERT (!isnan (-1.0L / 0.0L));
+  /* Quiet NaN.  */
+  ASSERT (isnan (0.0L / 0.0L));
+
+#if defined LDBL_EXPBIT0_WORD && defined LDBL_EXPBIT0_BIT
+  /* A bit pattern that is different from a Quiet NaN.  With a bit of luck,
+     it's a Signalling NaN.  */
+  {
+    memory_long_double m;
+    m.value = 0.0L / 0.0L;
+# if LDBL_EXPBIT0_BIT > 0
+    m.word[LDBL_EXPBIT0_WORD] ^= (unsigned int) 1 << (LDBL_EXPBIT0_BIT - 1);
+# else
+    m.word[LDBL_EXPBIT0_WORD + (LDBL_EXPBIT0_WORD < NWORDSL / 2 ? 1 : - 1)]
+      ^= (unsigned int) 1 << (sizeof (unsigned int) * CHAR_BIT - 1);
+# endif
+    m.word[LDBL_EXPBIT0_WORD + (LDBL_EXPBIT0_WORD < NWORDSL / 2 ? 1 : - 1)]
+      |= (unsigned int) 1 << LDBL_EXPBIT0_BIT;
+    ASSERT (isnan (m.value));
+  }
+#endif
+
+#if ((defined __ia64 && LDBL_MANT_DIG == 64) || (defined __x86_64__ || defined 
__amd64__) || (defined __i386 || defined __i386__ || defined _I386 || defined 
_M_IX86 || defined _X86_))
+/* Representation of an 80-bit 'long double' as an initializer for a sequence
+   of 'unsigned int' words.  */
+# ifdef WORDS_BIGENDIAN
+#  define LDBL80_WORDS(exponent,manthi,mantlo) \
+     { ((unsigned int) (exponent) << 16) | ((unsigned int) (manthi) >> 16), \
+       ((unsigned int) (manthi) << 16) | (unsigned int) (mantlo) >> 16),    \
+       (unsigned int) (mantlo) << 16                                        \
+     }
+# else
+#  define LDBL80_WORDS(exponent,manthi,mantlo) \
+     { mantlo, manthi, exponent }
+# endif
+  { /* Quiet NaN.  */
+    static memory_long_double x =
+      { LDBL80_WORDS (0xFFFF, 0xC3333333, 0x00000000) };
+    ASSERT (isnan (x.value));
+  }
+  {
+    /* Signalling NaN.  */
+    static memory_long_double x =
+      { LDBL80_WORDS (0xFFFF, 0x83333333, 0x00000000) };
+    ASSERT (isnan (x.value));
+  }
+  /* The isnan function should recognize Pseudo-NaNs, Pseudo-Infinities,
+     Pseudo-Zeroes, Unnormalized Numbers, and Pseudo-Denormals, as defined in
+       Intel IA-64 Architecture Software Developer's Manual, Volume 1:
+       Application Architecture.
+       Table 5-2 "Floating-Point Register Encodings"
+       Figure 5-6 "Memory to Floating-Point Register Data Translation"
+   */
+  { /* Pseudo-NaN.  */
+    static memory_long_double x =
+      { LDBL80_WORDS (0xFFFF, 0x40000001, 0x00000000) };
+    ASSERT (isnan (x.value));
+  }
+  { /* Pseudo-Infinity.  */
+    static memory_long_double x =
+      { LDBL80_WORDS (0xFFFF, 0x00000000, 0x00000000) };
+    ASSERT (isnan (x.value));
+  }
+  { /* Pseudo-Zero.  */
+    static memory_long_double x =
+      { LDBL80_WORDS (0x4004, 0x00000000, 0x00000000) };
+    ASSERT (isnan (x.value));
+  }
+  { /* Unnormalized number.  */
+    static memory_long_double x =
+      { LDBL80_WORDS (0x4000, 0x63333333, 0x00000000) };
+    ASSERT (isnan (x.value));
+  }
+  { /* Pseudo-Denormal.  */
+    static memory_long_double x =
+      { LDBL80_WORDS (0x0000, 0x83333333, 0x00000000) };
+    ASSERT (isnan (x.value));
+  }
+#endif
+}
+
+int
+main ()
+{
+  test_float ();
+  test_double ();
+  test_long_double ();
+  return 0;
+}

-- 
"A computer is a state machine.
 Threads are for people who cant [sic] program state machines."
--Alan Cox