Use __builtin_isnan with clang.

* lib/isnanf-nolibm.h (isnanf): Use the GCC built-in __builtin_isnan,
not __builtin_isnanf. Also on clang.
* m4/isnanf.m4 (gl_HAVE_ISNANF_NO_LIBM, gl_ISNANF_WORKS): Use the GCC
built-in __builtin_isnan, not __builtin_isnanf. Also on clang.
* lib/isnand-nolibm.h (isnand): With clang, use the GCC built-in.
* m4/isnand.m4 (gl_HAVE_ISNAND_IN_LIBM): With clang, use the GCC
built-in.
* lib/isnanl-nolibm.h (isnanf): Use the GCC built-in __builtin_isnan,
not __builtin_isnanl. Also on clang.
* m4/isnanl.m4 (gl_HAVE_ISNANL_NO_LIBM, gl_FUNC_ISNANL_WORKS): Use the
GCC built-in __builtin_isnan, not __builtin_isnanl. Also on clang.
* lib/math.in.h (__has_builtin): Remove macro.
(isnanf, gl_isnan_f): Use the GCC built-in __builtin_isnan, not
__builtin_isnanf. Also on clang.
(isnand, gl_isnan_d): With clang, use the GCC built-in.
(isnanl, gl_isnan_l): Use the GCC built-in __builtin_isnan, not
__builtin_isnanl. Also on clang.
(isnan): Use the GCC built-in __builtin_isnan in all three cases. Also
on clang.

1 files changed, 18 insertions, 22 deletions

diff --git a/lib/math.in.h b/lib/math.in.h
index 30465f8b2e..10514f1735 100644
--- a/lib/math.in.h
+++ b/lib/math.in.h
@@ -127,12 +127,6 @@ static void (*_gl_math_fix_itold) (long double *, int) = _Qp_itoq;
 #endif
 
 
-/* For clang: Use __has_builtin to determine whether a builtin is available.  */
-#ifndef __has_builtin
-# define __has_builtin(name) 0
-#endif
-
-
 /* POSIX allows platforms that don't support NAN.  But all major
    machines in the past 15 years have supported something close to
    IEEE NaN, so we define this unconditionally.  We also must define
@@ -2324,10 +2318,11 @@ _GL_WARN_REAL_FLOATING_DECL (isinf);
 # if @HAVE_ISNANF@
 /* The original <math.h> included above provides a declaration of isnan macro
    or (older) isnanf function.  */
-#  if __GNUC__ >= 4 && (!defined __clang__ || __has_builtin (__builtin_isnanf))
-    /* GCC 4.0 and newer provides three built-ins for isnan.  */
+#  if (__GNUC__ >= 4) || (__clang_major__ >= 4)
+    /* GCC >= 4.0 and clang provide a type-generic built-in for isnan.
+       GCC >= 4.0 also provides __builtin_isnanf, but clang doesn't.  */
 #   undef isnanf
-#   define isnanf(x) __builtin_isnanf ((float)(x))
+#   define isnanf(x) __builtin_isnan ((float)(x))
 #  elif defined isnan
 #   undef isnanf
 #   define isnanf(x) isnan ((float)(x))
@@ -2347,8 +2342,8 @@ _GL_EXTERN_C int isnanf (float x);
 # if @HAVE_ISNAND@
 /* The original <math.h> included above provides a declaration of isnan
    macro.  */
-#  if __GNUC__ >= 4
-    /* GCC 4.0 and newer provides three built-ins for isnan.  */
+#  if (__GNUC__ >= 4) || (__clang_major__ >= 4)
+    /* GCC >= 4.0 and clang provide a type-generic built-in for isnan.  */
 #   undef isnand
 #   define isnand(x) __builtin_isnan ((double)(x))
 #  else
@@ -2368,10 +2363,11 @@ _GL_EXTERN_C int isnand (double x);
 # if @HAVE_ISNANL@
 /* The original <math.h> included above provides a declaration of isnan
    macro or (older) isnanl function.  */
-#  if __GNUC__ >= 4 && (!defined __clang__ || __has_builtin (__builtin_isnanl))
-    /* GCC 4.0 and newer provides three built-ins for isnan.  */
+#  if (__GNUC__ >= 4) || (__clang_major__ >= 4)
+    /* GCC >= 4.0 and clang provide a type-generic built-in for isnan.
+       GCC >= 4.0 also provides __builtin_isnanl, but clang doesn't.  */
 #   undef isnanl
-#   define isnanl(x) __builtin_isnanl ((long double)(x))
+#   define isnanl(x) __builtin_isnan ((long double)(x))
 #  elif defined isnan
 #   undef isnanl
 #   define isnanl(x) isnan ((long double)(x))
@@ -2391,20 +2387,20 @@ _GL_EXTERN_C int isnanl (long double x) _GL_ATTRIBUTE_CONST;
    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 && (!defined __clang__ || __has_builtin (__builtin_isnanf))
-#   define gl_isnan_f(x) __builtin_isnanf ((float)(x))
+#  if @HAVE_ISNANF@ && (__GNUC__ >= 4) || (__clang_major__ >= 4)
+#   define gl_isnan_f(x) __builtin_isnan ((float)(x))
 #  else
 _GL_EXTERN_C int rpl_isnanf (float x);
 #   define gl_isnan_f(x) rpl_isnanf (x)
 #  endif
-#  if @HAVE_ISNAND@ && __GNUC__ >= 4
+#  if @HAVE_ISNAND@ && (__GNUC__ >= 4) || (__clang_major__ >= 4)
 #   define gl_isnan_d(x) __builtin_isnan ((double)(x))
 #  else
 _GL_EXTERN_C int rpl_isnand (double x);
 #   define gl_isnan_d(x) rpl_isnand (x)
 #  endif
-#  if @HAVE_ISNANL@ && __GNUC__ >= 4 && (!defined __clang__ || __has_builtin (__builtin_isnanl))
-#   define gl_isnan_l(x) __builtin_isnanl ((long double)(x))
+#  if @HAVE_ISNANL@ && (__GNUC__ >= 4) || (__clang_major__ >= 4)
+#   define gl_isnan_l(x) __builtin_isnan ((long double)(x))
 #  else
 _GL_EXTERN_C int rpl_isnanl (long double x) _GL_ATTRIBUTE_CONST;
 #   define gl_isnan_l(x) rpl_isnanl (x)
@@ -2414,12 +2410,12 @@ _GL_EXTERN_C int rpl_isnanl (long double x) _GL_ATTRIBUTE_CONST;
    (sizeof (x) == sizeof (long double) ? gl_isnan_l (x) : \
     sizeof (x) == sizeof (double) ? gl_isnan_d (x) : \
     gl_isnan_f (x))
-# elif __GNUC__ >= 4 && (!defined __clang__ || (__has_builtin (__builtin_isnanf) && __has_builtin (__builtin_isnanl)))
+# elif (__GNUC__ >= 4) || (__clang_major__ >= 4)
 #  undef isnan
 #  define isnan(x) \
-   (sizeof (x) == sizeof (long double) ? __builtin_isnanl ((long double)(x)) : \
+   (sizeof (x) == sizeof (long double) ? __builtin_isnan ((long double)(x)) : \
     sizeof (x) == sizeof (double) ? __builtin_isnan ((double)(x)) : \
-    __builtin_isnanf ((float)(x)))
+    __builtin_isnan ((float)(x)))
 # endif
 # ifdef __cplusplus
 #  if defined isnan || defined GNULIB_NAMESPACE