X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Fsignbit.m4;h=40ef49c67a234dc8b5baf7babd7cfa62ee7f856b;hb=8eaac7a51d093dbcecc0c2b42a5762a882b4517b;hp=152a32e567d9ef3c23b3cf9c79790badff94df59;hpb=ce8675631414567e50a77fdd43196f5882172ca7;p=gnulib.git

diff --git a/m4/signbit.m4 b/m4/signbit.m4
index 152a32e56..40ef49c67 100644
--- a/m4/signbit.m4
+++ b/m4/signbit.m4
@@ -1,4 +1,4 @@
-# signbit.m4 serial 3
+# signbit.m4 serial 4
 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,
@@ -123,13 +123,21 @@ AC_DEFUN([gl_SIGNBIT],
   fi
 ])
 
-AC_DEFUN([gl_SIGNBIT_TEST_PROGRAM], [
+AC_DEFUN([gl_SIGNBIT_TEST_PROGRAM], [[
+/* 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;
-float m0f = -0.0f;
+float m0f = -p0f;
 double p0d = 0.0;
-double m0d = -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.  */
 long double p0l = 0.0L;
-long double m0l = -0.0L;
+#ifdef __hpux
+long double m0l = -LDBL_MIN * LDBL_MIN;
+#else
+long double m0l = -p0l;
+#endif
 int main ()
 {
   {
@@ -167,7 +175,7 @@ int main ()
   }
   return 0;
 }
-])
+]])
 
 AC_DEFUN([gl_FLOAT_SIGN_LOCATION],
 [