NEWS.stable: update and finalise

[gnulib.git] / m4 / frexp.m4

diff --git a/m4/frexp.m4 b/m4/frexp.m4
index 6c91112..2e0fb3b 100644 (file)
--- a/m4/frexp.m4
+++ b/m4/frexp.m4
@@ -1,5 +1,5 @@
-# frexp.m4 serial 7
-dnl Copyright (C) 2007, 2008, 2009 Free Software Foundation, Inc.
+# frexp.m4 serial 10
+dnl Copyright (C) 2007-2011 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.
@@ -7,25 +7,19 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN([gl_FUNC_FREXP],
 [
   AC_REQUIRE([gl_MATH_H_DEFAULTS])
+  AC_REQUIRE([gl_CHECK_FREXP_NO_LIBM])
   FREXP_LIBM=
-  AC_CACHE_CHECK([whether frexp() can be used without linking with libm],
-    [gl_cv_func_frexp_no_libm],
-    [
-      AC_TRY_LINK([#include <math.h>
-                   double x;],
-                  [int e; return frexp (x, &e) > 0;],
-        [gl_cv_func_frexp_no_libm=yes],
-        [gl_cv_func_frexp_no_libm=no])
-    ])
   if test $gl_cv_func_frexp_no_libm = no; then
     AC_CACHE_CHECK([whether frexp() can be used with libm],
       [gl_cv_func_frexp_in_libm],
       [
         save_LIBS="$LIBS"
         LIBS="$LIBS -lm"
-        AC_TRY_LINK([#include <math.h>
-                     double x;],
-                    [int e; return frexp (x, &e) > 0;],
+        AC_LINK_IFELSE(
+          [AC_LANG_PROGRAM(
+             [[#include <math.h>
+               double x;]],
+             [[int e; return frexp (x, &e) > 0;]])],
           [gl_cv_func_frexp_in_libm=yes],
           [gl_cv_func_frexp_in_libm=no])
         LIBS="$save_LIBS"
@@ -59,15 +53,7 @@ AC_DEFUN([gl_FUNC_FREXP],
 AC_DEFUN([gl_FUNC_FREXP_NO_LIBM],
 [
   AC_REQUIRE([gl_MATH_H_DEFAULTS])
-  AC_CACHE_CHECK([whether frexp() can be used without linking with libm],
-    [gl_cv_func_frexp_no_libm],
-    [
-      AC_TRY_LINK([#include <math.h>
-                   double x;],
-                  [int e; return frexp (x, &e) > 0;],
-        [gl_cv_func_frexp_no_libm=yes],
-        [gl_cv_func_frexp_no_libm=no])
-    ])
+  AC_REQUIRE([gl_CHECK_FREXP_NO_LIBM])
   if test $gl_cv_func_frexp_no_libm = yes; then
     gl_FUNC_FREXP_WORKS
     case "$gl_cv_func_frexp_works" in
@@ -87,6 +73,23 @@ AC_DEFUN([gl_FUNC_FREXP_NO_LIBM],
   fi
 ])
 
+dnl Test whether frexp() can be used without linking with libm.
+dnl Set gl_cv_func_frexp_no_libm to 'yes' or 'no' accordingly.
+AC_DEFUN([gl_CHECK_FREXP_NO_LIBM],
+[
+  AC_CACHE_CHECK([whether frexp() can be used without linking with libm],
+    [gl_cv_func_frexp_no_libm],
+    [
+      AC_LINK_IFELSE(
+        [AC_LANG_PROGRAM(
+           [[#include <math.h>
+             double x;]],
+           [[int e; return frexp (x, &e) > 0;]])],
+        [gl_cv_func_frexp_no_libm=yes],
+        [gl_cv_func_frexp_no_libm=no])
+    ])
+])
+
 dnl Test whether frexp() works also on denormalized numbers (this fails e.g. on
 dnl NetBSD 3.0), on infinite numbers (this fails e.g. on IRIX 6.5 and mingw),
 dnl and on negative zero (this fails e.g. on NetBSD 4.99).
@@ -96,16 +99,30 @@ AC_DEFUN([gl_FUNC_FREXP_WORKS],
   AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
   AC_CACHE_CHECK([whether frexp works], [gl_cv_func_frexp_works],
     [
-      AC_TRY_RUN([
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
 #include <float.h>
 #include <math.h>
 #include <string.h>
+/* HP cc on HP-UX 10.20 has a bug with the constant expression -0.0.
+   ICC 10.0 has a bug when optimizing the expression -zero.
+   The expression -DBL_MIN * DBL_MIN does not work when cross-compiling
+   to PowerPC on MacOS X 10.5.  */
+#if defined __hpux || defined __sgi || defined __ICC
+static double
+compute_minus_zero (void)
+{
+  return -DBL_MIN * DBL_MIN;
+}
+# define minus_zero compute_minus_zero ()
+#else
+double minus_zero = -0.0;
+#endif
 int main()
 {
+  int result = 0;
   int i;
   volatile double x;
-/* HP cc on HP-UX 10.20 has a bug with the constant expression -0.0.
-   So we use -zero instead.  */
   double zero = 0.0;
   /* Test on denormalized numbers.  */
   for (i = 1, x = 1.0; i >= DBL_MIN_EXP; i--, x *= 0.5)
@@ -117,7 +134,7 @@ int main()
       /* On machines with IEEE754 arithmetic: x = 1.11254e-308, exp = -1022.
          On NetBSD: y = 0.75. Correct: y = 0.5.  */
       if (y != 0.5)
-        return 1;
+        result |= 1;
     }
   /* Test on infinite numbers.  */
   x = 1.0 / 0.0;
@@ -125,22 +142,24 @@ int main()
     int exp;
     double y = frexp (x, &exp);
     if (y != x)
-      return 1;
+      result |= 2;
   }
   /* Test on negative zero.  */
-  x = -zero;
+  x = minus_zero;
   {
     int exp;
     double y = frexp (x, &exp);
     if (memcmp (&y, &x, sizeof x))
-      return 1;
+      result |= 4;
   }
-  return 0;
-}], [gl_cv_func_frexp_works=yes], [gl_cv_func_frexp_works=no],
-      [case "$host_os" in
-         netbsd* | irix* | mingw*) gl_cv_func_frexp_works="guessing no";;
-         *)                        gl_cv_func_frexp_works="guessing yes";;
-       esac
-      ])
+  return result;
+}]])],
+        [gl_cv_func_frexp_works=yes],
+        [gl_cv_func_frexp_works=no],
+        [case "$host_os" in
+           netbsd* | irix* | mingw*) gl_cv_func_frexp_works="guessing no";;
+           *)                        gl_cv_func_frexp_works="guessing yes";;
+         esac
+        ])
     ])
 ])