NEWS.stable: log cherry-pick [d828cda]->[6add58a] imaxdiv: Avoid link error on OSF...

[gnulib.git] / m4 / roundf.m4

diff --git a/m4/roundf.m4 b/m4/roundf.m4
index a105760..9c21340 100644 (file)
--- a/m4/roundf.m4
+++ b/m4/roundf.m4
@@ -1,11 +1,12 @@
-# roundf.m4 serial 9
-dnl Copyright (C) 2007-2010 Free Software Foundation, Inc.
+# roundf.m4 serial 13
+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.
 
 AC_DEFUN([gl_FUNC_ROUNDF],
 [
+  m4_divert_text([DEFAULTS], [gl_roundf_required=plain])
   AC_REQUIRE([gl_MATH_H_DEFAULTS])
   dnl Persuade glibc <math.h> to declare roundf().
   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
@@ -50,11 +51,51 @@ int main()
     if test "$ROUNDF_LIBM" = missing; then
       REPLACE_ROUNDF=1
     fi
+    m4_ifdef([gl_FUNC_ROUNDF_IEEE], [
+      if test $gl_roundf_required = ieee && test $REPLACE_ROUNDF = 0; then
+        AC_CACHE_CHECK([whether roundf works according to ISO C 99 with IEC 60559],
+          [gl_cv_func_roundf_ieee],
+          [
+            save_LIBS="$LIBS"
+            LIBS="$LIBS $ROUNDF_LIBM"
+            AC_RUN_IFELSE(
+              [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include <math.h>
+]gl_FLOAT_MINUS_ZERO_CODE[
+]gl_FLOAT_SIGNBIT_CODE[
+static float dummy (float f) { return 0; }
+int main (int argc, char *argv[])
+{
+  float (*my_roundf) (float) = argc ? roundf : dummy;
+  int result = 0;
+  /* Test whether roundf (-0.0f) is -0.0f.  */
+  if (signbitf (minus_zerof) && !signbitf (my_roundf (minus_zerof)))
+    result |= 1;
+  /* Test whether roundf (-0.3f) is -0.0f.  */
+  if (signbitf (-0.3f) && !signbitf (my_roundf (-0.3f)))
+    result |= 2;
+  return result;
+}
+              ]])],
+              [gl_cv_func_roundf_ieee=yes],
+              [gl_cv_func_roundf_ieee=no],
+              [gl_cv_func_roundf_ieee="guessing no"])
+            LIBS="$save_LIBS"
+          ])
+        case "$gl_cv_func_roundf_ieee" in
+          *yes) ;;
+          *) REPLACE_ROUNDF=1 ;;
+        esac
+      fi
+    ])
   else
     HAVE_DECL_ROUNDF=0
   fi
   if test $HAVE_DECL_ROUNDF = 0 || test $REPLACE_ROUNDF = 1; then
-    AC_LIBOBJ([roundf])
+    dnl Find libraries needed to link lib/roundf.c.
     AC_CHECK_DECLS([ceilf, floorf], , , [#include <math.h>])
     if test "$ac_cv_have_decl_floorf" = yes \
        && test "$ac_cv_have_decl_ceilf" = yes; then