X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Fsignbit.m4;h=56ff825f985c45e461150b80dd15b0949a57ab6a;hb=062cad2d07081f9a60adbb90fc1184a435a1a93f;hp=40ef49c67a234dc8b5baf7babd7cfa62ee7f856b;hpb=ea0f5bf6444c14f97c069b5da723781ecb8a84aa;p=gnulib.git

diff --git a/m4/signbit.m4 b/m4/signbit.m4
index 40ef49c67..56ff825f9 100644
--- a/m4/signbit.m4
+++ b/m4/signbit.m4
@@ -1,5 +1,5 @@
-# signbit.m4 serial 4
-dnl Copyright (C) 2007-2008 Free Software Foundation, Inc.
+# signbit.m4 serial 6
+dnl Copyright (C) 2007-2010 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.
@@ -74,7 +74,7 @@ AC_DEFUN([gl_SIGNBIT],
                 [gl_cv_func_copysignf_no_libm=no])
             ])
           if test $gl_cv_func_copysignf_no_libm = yes; then
-            AC_DEFINE([HAVE_COPYSIGNF_IN_LIBC], 1,
+            AC_DEFINE([HAVE_COPYSIGNF_IN_LIBC], [1],
               [Define if the copysignf function is declared in <math.h> and available in libc.])
           fi
         fi
@@ -94,7 +94,7 @@ AC_DEFUN([gl_SIGNBIT],
                 [gl_cv_func_copysign_no_libm=no])
             ])
           if test $gl_cv_func_copysign_no_libm = yes; then
-            AC_DEFINE([HAVE_COPYSIGN_IN_LIBC], 1,
+            AC_DEFINE([HAVE_COPYSIGN_IN_LIBC], [1],
               [Define if the copysign function is declared in <math.h> and available in libc.])
           fi
         fi
@@ -114,7 +114,7 @@ AC_DEFUN([gl_SIGNBIT],
                 [gl_cv_func_copysignl_no_libm=no])
             ])
           if test $gl_cv_func_copysignl_no_libm = yes; then
-            AC_DEFINE([HAVE_COPYSIGNL_IN_LIBC], 1,
+            AC_DEFINE([HAVE_COPYSIGNL_IN_LIBC], [1],
               [Define if the copysignl function is declared in <math.h> and available in libc.])
           fi
         fi
@@ -124,6 +124,14 @@ AC_DEFUN([gl_SIGNBIT],
 ])
 
 AC_DEFUN([gl_SIGNBIT_TEST_PROGRAM], [[
+/* Global variables.
+   Needed because GCC 4 constant-folds __builtin_signbitl (literal)
+   but cannot constant-fold            __builtin_signbitl (variable).  */
+float vf;
+double vd;
+long double vl;
+int main ()
+{
 /* HP cc on HP-UX 10.20 has a bug with the constant expression -0.0.
    So we use -p0f and -p0d instead.  */
 float p0f = 0.0f;
@@ -131,15 +139,17 @@ float m0f = -p0f;
 double p0d = 0.0;
 double m0d = -p0d;
 /* On HP-UX 10.20, negating 0.0L does not yield -0.0L.
-   So we use another constant expression instead.  */
+   So we use another constant expression instead.
+   But that expression does not work on other platforms, such as when
+   cross-compiling to PowerPC on MacOS X 10.5.  */
 long double p0l = 0.0L;
-#ifdef __hpux
+#if defined __hpux || defined __sgi
 long double m0l = -LDBL_MIN * LDBL_MIN;
 #else
 long double m0l = -p0l;
 #endif
-int main ()
-{
+  if (signbit (vf))
+    vf++;
   {
     float plus_inf = 1.0f / p0f;
     float minus_inf = -1.0f / p0f;
@@ -151,6 +161,8 @@ int main ()
           && signbit (minus_inf)))
       return 1;
   }
+  if (signbit (vd))
+    vd++;
   {
     double plus_inf = 1.0 / p0d;
     double minus_inf = -1.0 / p0d;
@@ -162,6 +174,8 @@ int main ()
           && signbit (minus_inf)))
       return 1;
   }
+  if (signbit (vl))
+    vl++;
   {
     long double plus_inf = 1.0L / p0l;
     long double minus_inf = -1.0L / p0l;