--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,16 @@
+2010-12-21  Bruno Haible  <bruno@clisp.org>
+
+	New module 'ceilf-ieee'.
+	* modules/ceilf-ieee: New file.
+	* m4/ceilf.m4 (gl_FUNC_FLOORF): If gl_FUNC_CEILF_IEEE is also used,
+	test whether ceilf works according to ISO C 99 with IEC 60559.
+	* m4/ceilf-ieee.m4: New file.
+	* modules/ceilf-ieee-tests: New file.
+	* tests/test-ceilf-ieee.c: New file, based on tests/test-ceilf1.c.
+	* tests/test-ceilf1.c (main): Remove signbit tests.
+	* modules/ceilf-tests (Depends-on): Remove 'signbit'.
+	* doc/posix-functions/ceilf.texi: Mention the new module.
+
 2010-12-21  Bruno Haible  <bruno@clisp.org>
 
 	New module 'floorf-ieee'.

--- a/doc/posix-functions/ceilf.texi
+++ b/doc/posix-functions/ceilf.texi
@@ -4,15 +4,23 @@
 
 POSIX specification:@* @url{http://www.opengroup.org/onlinepubs/9699919799/functions/ceilf.html}
 
-Gnulib module: ceilf
+Gnulib module: ceilf or ceilf-ieee
 
-Portability problems fixed by Gnulib:
+Portability problems fixed by either Gnulib module @code{ceilf} or @code{ceilf-ieee}:
 @itemize
 @item
 This function is missing on some platforms:
 AIX 5.1, HP-UX 11, Solaris 9.
 @end itemize
 
+Portability problems fixed by Gnulib module @code{ceilf-ieee}:
+@itemize
+@item
+This function returns a positive zero for a minus zero argument
+on some platforms:
+OSF/1 5.1.
+@end itemize
+
 Portability problems not fixed by Gnulib:
 @itemize
 @end itemize

new file mode 100644
--- /dev/null
+++ b/m4/ceilf-ieee.m4
@@ -0,0 +1,15 @@
+# ceilf-ieee.m4 serial 1
+dnl Copyright (C) 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.
+
+dnl This macro is in a separate file (not in ceilf.m4 and not inlined in the
+dnl module description), so that gl_FUNC_CEILF can test whether 'aclocal' has
+dnl found uses of this macro.
+
+AC_DEFUN([gl_FUNC_CEILF_IEEE],
+[
+  m4_divert_text([INIT_PREPARE], [gl_ceilf_required=ieee])
+  AC_REQUIRE([gl_FUNC_CEILF])
+])

--- a/m4/ceilf.m4
+++ b/m4/ceilf.m4
@@ -1,4 +1,4 @@
-# ceilf.m4 serial 7
+# ceilf.m4 serial 8
 dnl Copyright (C) 2007, 2009-2010 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -6,6 +6,7 @@
 
 AC_DEFUN([gl_FUNC_CEILF],
 [
+  m4_divert_text([DEFAULTS], [gl_ceilf_required=plain])
   AC_REQUIRE([gl_MATH_H_DEFAULTS])
   dnl Persuade glibc <math.h> to declare ceilf().
   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
@@ -19,6 +20,40 @@
       dnl libm.so, but not in the libm.so that the compiler uses.
       REPLACE_CEILF=1
     fi
+    m4_ifdef([gl_FUNC_CEILF_IEEE], [
+      if test $gl_ceilf_required = ieee && test $REPLACE_CEILF = 0; then
+        AC_CACHE_CHECK([whether ceilf works according to ISO C 99 with IEC 60559],
+          [gl_cv_func_ceilf_ieee],
+          [
+            save_LIBS="$LIBS"
+            LIBS="$LIBS $CEILF_LIBM"
+            AC_RUN_IFELSE(
+              [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include <math.h>
+]gl_FLOAT_MINUS_ZERO_CODE[
+]gl_FLOAT_SIGNBIT_CODE[
+int main()
+{
+  /* Test whether ceilf (-0.0f) is -0.0f.  */
+  if (signbitf (minus_zerof) && !signbitf (ceilf (minus_zerof)))
+    return 1;
+  return 0;
+}
+              ]])],
+              [gl_cv_func_ceilf_ieee=yes],
+              [gl_cv_func_ceilf_ieee=no],
+              [gl_cv_func_ceilf_ieee="guessing no"])
+            LIBS="$save_LIBS"
+          ])
+        case "$gl_cv_func_ceilf_ieee" in
+          *yes) ;;
+          *) REPLACE_CEILF=1 ;;
+        esac
+      fi
+    ])
   else
     HAVE_DECL_CEILF=0
   fi

new file mode 100644
--- /dev/null
+++ b/modules/ceilf-ieee
@@ -0,0 +1,27 @@
+Description:
+ceilf() function according to ISO C 99 with IEC 60559.
+
+Files:
+m4/ceilf-ieee.m4
+m4/minus-zero.m4
+m4/signbit.m4
+
+Depends-on:
+ceilf
+
+configure.ac:
+gl_FUNC_CEILF_IEEE
+
+Makefile.am:
+
+Include:
+<math.h>
+
+Link:
+$(CEILF_LIBM)
+
+License:
+LGPL
+
+Maintainer:
+Bruno Haible

new file mode 100644
--- /dev/null
+++ b/modules/ceilf-ieee-tests
@@ -0,0 +1,15 @@
+Files:
+tests/test-ceilf-ieee.c
+tests/minus-zero.h
+tests/macros.h
+
+Depends-on:
+float
+signbit
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-ceilf-ieee
+check_PROGRAMS += test-ceilf-ieee
+test_ceilf_ieee_LDADD = $(LDADD) @CEILF_LIBM@

--- a/modules/ceilf-tests
+++ b/modules/ceilf-tests
@@ -9,7 +9,6 @@
 Depends-on:
 float
 isnanf-nolibm
-signbit
 stdbool
 stdint
 

new file mode 100644
--- /dev/null
+++ b/tests/test-ceilf-ieee.c
@@ -0,0 +1,45 @@
+/* Test of rounding towards positive infinity.
+   Copyright (C) 2010 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+#include <math.h>
+
+#include "minus-zero.h"
+#include "macros.h"
+
+/* If IEEE compliance was not requested, the ICC compiler inlines its
+   own ceilf assembly that turns -0.0f to 0.0f; but that is a correct
+   result when IEEE is not enforced.  To avoid spurious failure, we
+   have to provide this dummy function in order to outsmart ICC's
+   inlining, and call our ceilf through a function pointer.  */
+static float
+dummy (float f)
+{
+  return 0;
+}
+
+int
+main (int argc, char **argv _GL_UNUSED)
+{
+  float (*my_ceilf) (float) = argc ? ceilf : dummy;
+
+  /* Zero.  */
+  ASSERT (!signbit (my_ceilf (0.0f)));
+  ASSERT (!!signbit (my_ceilf (minus_zerof)) == !!signbit (minus_zerof));
+
+  return 0;
+}

--- a/tests/test-ceilf1.c
+++ b/tests/test-ceilf1.c
@@ -46,9 +46,7 @@
 
   /* Zero.  */
   ASSERT (my_ceilf (0.0f) == 0.0f);
-  ASSERT (!signbit (my_ceilf (0.0f)));
   ASSERT (my_ceilf (minus_zerof) == 0.0f);
-  ASSERT (!!signbit (minus_zerof) == !!signbit (my_ceilf (minus_zerof)));
   /* Positive numbers.  */
   ASSERT (my_ceilf (0.3f) == 1.0f);
   ASSERT (my_ceilf (0.7f) == 1.0f);