X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Froundf.m4;h=3a3fd6b5a0447d477703f4101a255a80dd8dfea3;hb=46f5f314f34a08c9305758482d7d2fdb0e999d09;hp=b246d0432d33e7e890e5bbaeda24abbe9b832c7b;hpb=692679fcbebba0095bae0f1f1a99bd1f0f5a0476;p=gnulib.git

diff --git a/m4/roundf.m4 b/m4/roundf.m4
index b246d0432..3a3fd6b5a 100644
--- a/m4/roundf.m4
+++ b/m4/roundf.m4
@@ -1,19 +1,30 @@
-# roundf.m4 serial 8
-dnl Copyright (C) 2007-2010 Free Software Foundation, Inc.
+# roundf.m4 serial 17
+dnl Copyright (C) 2007-2014 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])
-  AC_CHECK_DECLS([roundf], , , [#include <math.h>])
-  if test "$ac_cv_have_decl_roundf" = yes; then
-    gl_CHECK_MATH_LIB([ROUNDF_LIBM], [x = roundf (x);])
-  fi
-  if test "$ac_cv_have_decl_roundf" = yes && test "$ROUNDF_LIBM" != missing; then
+
+  gl_CHECK_MATH_LIB([ROUNDF_LIBM], [x = roundf (x);],
+    [extern
+     #ifdef __cplusplus
+     "C"
+     #endif
+     float roundf (float);
+    ])
+  if test "$ROUNDF_LIBM" != missing; then
+    HAVE_ROUNDF=1
+    dnl Also check whether it's declared.
+    dnl IRIX 6.5 has roundf() in libm but doesn't declare it in <math.h>.
+    AC_CHECK_DECLS([roundf], , [HAVE_DECL_ROUNDF=0], [[#include <math.h>]])
+
     dnl Test whether roundf() produces correct results. On mingw, for
     dnl x = 1/2 - 2^-25, the system's roundf() returns a wrong result.
     AC_REQUIRE([AC_PROG_CC])
@@ -25,6 +36,14 @@ AC_DEFUN([gl_FUNC_ROUNDF],
         AC_RUN_IFELSE([AC_LANG_SOURCE([[
 #include <float.h>
 #include <math.h>
+extern
+#ifdef __cplusplus
+"C"
+#endif
+float roundf (float);
+#ifdef _MSC_VER
+# pragma fenv_access (off)
+#endif
 int main()
 {
   /* 2^FLT_MANT_DIG.  */
@@ -45,13 +64,68 @@ int main()
         LIBS="$save_LIBS"
       ])
     case "$gl_cv_func_roundf_works" in
-      *no) ROUNDF_LIBM=missing ;;
+      *no) REPLACE_ROUNDF=1 ;;
     esac
+
+    m4_ifdef([gl_FUNC_ROUNDF_IEEE], [
+      if test $gl_roundf_required = ieee && test $REPLACE_ROUNDF = 0; then
+        AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+        AC_CACHE_CHECK([whether roundf works according to ISO C 99 with IEC 60559],
+          [gl_cv_func_roundf_ieee],
+          [
+            save_LIBS="$LIBS"
+            LIBS="$LIBS $ROUNDF_LIBM"
+            AC_RUN_IFELSE(
+              [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include <math.h>
+extern
+#ifdef __cplusplus
+"C"
+#endif
+float roundf (float);
+]gl_FLOAT_MINUS_ZERO_CODE[
+]gl_FLOAT_SIGNBIT_CODE[
+static float dummy (float f) { return 0; }
+int main (int argc, char *argv[])
+{
+  float (*my_roundf) (float) = argc ? roundf : dummy;
+  int result = 0;
+  /* Test whether roundf (-0.0f) is -0.0f.  */
+  if (signbitf (minus_zerof) && !signbitf (my_roundf (minus_zerof)))
+    result |= 1;
+  /* Test whether roundf (-0.3f) is -0.0f.  */
+  if (signbitf (-0.3f) && !signbitf (my_roundf (-0.3f)))
+    result |= 2;
+  return result;
+}
+              ]])],
+              [gl_cv_func_roundf_ieee=yes],
+              [gl_cv_func_roundf_ieee=no],
+              [case "$host_os" in
+                         # Guess yes on glibc systems.
+                 *-gnu*) gl_cv_func_roundf_ieee="guessing yes" ;;
+                         # If we don't know, assume the worst.
+                 *)      gl_cv_func_roundf_ieee="guessing no" ;;
+               esac
+              ])
+            LIBS="$save_LIBS"
+          ])
+        case "$gl_cv_func_roundf_ieee" in
+          *yes) ;;
+          *) REPLACE_ROUNDF=1 ;;
+        esac
+      fi
+    ])
+  else
+    HAVE_ROUNDF=0
+    HAVE_DECL_ROUNDF=0
   fi
-  if test "$ac_cv_have_decl_roundf" != yes || test "$ROUNDF_LIBM" = missing; then
-    REPLACE_ROUNDF=1
-    AC_LIBOBJ([roundf])
-    AC_CHECK_DECLS([ceilf, floorf], , , [#include <math.h>])
+  if test $HAVE_ROUNDF = 0 || test $REPLACE_ROUNDF = 1; then
+    dnl Find libraries needed to link lib/roundf.c.
+    AC_CHECK_DECLS([ceilf, floorf], , , [[#include <math.h>]])
     if test "$ac_cv_have_decl_floorf" = yes \
        && test "$ac_cv_have_decl_ceilf" = yes; then
       gl_FUNC_FLOORF_LIBS