X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Ffrexp.m4;h=125edcdc45d0db747d9e258ff88b630cf41c4c43;hb=d9c5af0679bed502b1f978f75cf8a4c41e104263;hp=b0f0d73258eb69a863e403bad6453b82cd0a7252;hpb=ffa7dae3061b0b0870da00f1f88d44e61cd4c3e2;p=gnulib.git

diff --git a/m4/frexp.m4 b/m4/frexp.m4
index b0f0d7325..125edcdc4 100644
--- a/m4/frexp.m4
+++ b/m4/frexp.m4
@@ -1,5 +1,5 @@
-# frexp.m4 serial 1
-dnl Copyright (C) 2007 Free Software Foundation, Inc.
+# frexp.m4 serial 11
+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>
-                   long 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="$LIBS -lm"
-        AC_TRY_LINK([#include <math.h>
-                     long double x;],
-                    [int e; return frexp (x, &e) > 0;],
+        AC_LINK_IFELSE(
+          [AC_LANG_PROGRAM(
+             [[#include <math.h>
+               double x;]],
+             [[int e; return frexp (x, &e) > 0;]])],
           [gl_cv_func_frexp_in_libm=yes],
           [gl_cv_func_frexp_in_libm=no])
         LIBS="$save_LIBS"
@@ -48,28 +42,85 @@ AC_DEFUN([gl_FUNC_FREXP],
     gl_func_frexp=no
   fi
   if test $gl_func_frexp = yes; then
-    AC_DEFINE([HAVE_FREXP], 1,
+    AC_DEFINE([HAVE_FREXP], [1],
       [Define if the frexp() function is available and works.])
+  fi
+  AC_SUBST([FREXP_LIBM])
+])
+
+AC_DEFUN([gl_FUNC_FREXP_NO_LIBM],
+[
+  AC_REQUIRE([gl_MATH_H_DEFAULTS])
+  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
+      *yes) gl_func_frexp_no_libm=yes ;;
+      *)    gl_func_frexp_no_libm=no; REPLACE_FREXP=1 ;;
+    esac
   else
-    AC_LIBOBJ([frexp])
+    gl_func_frexp_no_libm=no
+    dnl Set REPLACE_FREXP here because the system may have frexp in libm.
+    REPLACE_FREXP=1
+  fi
+  if test $gl_func_frexp_no_libm = yes; then
+    AC_DEFINE([HAVE_FREXP_IN_LIBC], [1],
+      [Define if the frexp() function is available in libc.])
   fi
 ])
 
-dnl Test whether frexp() works also on denormalized numbers.
-dnl This test fails e.g. on NetBSD.
+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 and mingw).
 AC_DEFUN([gl_FUNC_FREXP_WORKS],
 [
   AC_REQUIRE([AC_PROG_CC])
   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;
+  double zero = 0.0;
+  /* Test on denormalized numbers.  */
   for (i = 1, x = 1.0; i >= DBL_MIN_EXP; i--, x *= 0.5)
     ;
   if (x > 0.0)
@@ -79,14 +130,32 @@ 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;
     }
-  return 0;
-}], [gl_cv_func_frexp_works=yes], [gl_cv_func_frexp_works=no],
-      [case "$host_os" in
-         netbsd*) gl_cv_func_frexp_works="guessing no";;
-         *)       gl_cv_func_frexp_works="guessing yes";;
-       esac
-      ])
+  /* Test on infinite numbers.  */
+  x = 1.0 / 0.0;
+  {
+    int exp;
+    double y = frexp (x, &exp);
+    if (y != x)
+      result |= 2;
+  }
+  /* Test on negative zero.  */
+  x = minus_zero;
+  {
+    int exp;
+    double y = frexp (x, &exp);
+    if (memcmp (&y, &x, sizeof x))
+      result |= 4;
+  }
+  return result;
+}]])],
+        [gl_cv_func_frexp_works=yes],
+        [gl_cv_func_frexp_works=no],
+        [case "$host_os" in
+           netbsd* | irix* | mingw*) gl_cv_func_frexp_works="guessing no";;
+           *)                        gl_cv_func_frexp_works="guessing yes";;
+         esac
+        ])
     ])
 ])