X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Ffloorf.m4;h=aa76f8cae20e323285e2e8862e41834db5f7678e;hb=a6b16b69fe1cad695b270dd5bf3deb2850fc4dd1;hp=8cdaa94662f28872ba71edef48fa222311abd74e;hpb=1e2cfbcdde717ff46d2b5afe4aa2dc3901074451;p=gnulib.git

diff --git a/m4/floorf.m4 b/m4/floorf.m4
index 8cdaa9466..aa76f8cae 100644
--- a/m4/floorf.m4
+++ b/m4/floorf.m4
@@ -1,11 +1,12 @@
-# floorf.m4 serial 3
-dnl Copyright (C) 2007 Free Software Foundation, Inc.
+# floorf.m4 serial 10
+dnl Copyright (C) 2007, 2009-2011 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_FLOORF],
 [
+  m4_divert_text([DEFAULTS], [gl_floorf_required=plain])
   AC_REQUIRE([gl_MATH_H_DEFAULTS])
   dnl Persuade glibc <math.h> to declare floorf().
   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
@@ -19,14 +20,49 @@ AC_DEFUN([gl_FUNC_FLOORF],
       dnl libm.so, but not in the libm.so that the compiler uses.
       REPLACE_FLOORF=1
     fi
+    m4_ifdef([gl_FUNC_FLOORF_IEEE], [
+      if test $gl_floorf_required = ieee && test $REPLACE_FLOORF = 0; then
+        AC_CACHE_CHECK([whether floorf works according to ISO C 99 with IEC 60559],
+          [gl_cv_func_floorf_ieee],
+          [
+            save_LIBS="$LIBS"
+            LIBS="$LIBS $FLOORF_LIBM"
+            AC_RUN_IFELSE(
+              [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include <math.h>
+]gl_FLOAT_MINUS_ZERO_CODE[
+]gl_FLOAT_SIGNBIT_CODE[
+static float dummy (float f) { return 0; }
+int main (int argc, char *argv[])
+{
+  float (*my_floorf) (float) = argc ? floorf : dummy;
+  /* Test whether floorf (-0.0f) is -0.0f.  */
+  if (signbitf (minus_zerof) && !signbitf (my_floorf (minus_zerof)))
+    return 1;
+  return 0;
+}
+              ]])],
+              [gl_cv_func_floorf_ieee=yes],
+              [gl_cv_func_floorf_ieee=no],
+              [gl_cv_func_floorf_ieee="guessing no"])
+            LIBS="$save_LIBS"
+          ])
+        case "$gl_cv_func_floorf_ieee" in
+          *yes) ;;
+          *) REPLACE_FLOORF=1 ;;
+        esac
+      fi
+    ])
   else
-    REPLACE_FLOORF=1
+    HAVE_DECL_FLOORF=0
   fi
-  if test $REPLACE_FLOORF = 1; then
-    AC_LIBOBJ([floorf])
+  if test $HAVE_DECL_FLOORF = 0 || test $REPLACE_FLOORF = 1; then
+    dnl No libraries are needed to link lib/floorf.c.
     FLOORF_LIBM=
   fi
-  AC_SUBST([REPLACE_FLOORF])
   AC_SUBST([FLOORF_LIBM])
 ])
 
@@ -34,26 +70,28 @@ AC_DEFUN([gl_FUNC_FLOORF],
 # Sets FLOORF_LIBM.
 AC_DEFUN([gl_FUNC_FLOORF_LIBS],
 [
-  AC_CACHE_VAL([gl_cv_func_floorf_libm], [
+  gl_CACHE_VAL_SILENT([gl_cv_func_floorf_libm], [
     gl_cv_func_floorf_libm=?
-    AC_TRY_LINK([
-       #ifndef __NO_MATH_INLINES
-       # define __NO_MATH_INLINES 1 /* for glibc */
-       #endif
-       #include <math.h>
-       float x;],
-      [x = floorf(x);],
+    AC_LINK_IFELSE(
+      [AC_LANG_PROGRAM(
+         [[#ifndef __NO_MATH_INLINES
+           # define __NO_MATH_INLINES 1 /* for glibc */
+           #endif
+           #include <math.h>
+           float x;]],
+         [[x = floorf(x);]])],
       [gl_cv_func_floorf_libm=])
     if test "$gl_cv_func_floorf_libm" = "?"; then
       save_LIBS="$LIBS"
       LIBS="$LIBS -lm"
-      AC_TRY_LINK([
-         #ifndef __NO_MATH_INLINES
-         # define __NO_MATH_INLINES 1 /* for glibc */
-         #endif
-         #include <math.h>
-         float x;],
-        [x = floorf(x);],
+      AC_LINK_IFELSE(
+        [AC_LANG_PROGRAM(
+           [[#ifndef __NO_MATH_INLINES
+             # define __NO_MATH_INLINES 1 /* for glibc */
+             #endif
+             #include <math.h>
+             float x;]],
+           [[x = floorf(x);]])],
         [gl_cv_func_floorf_libm="-lm"])
       LIBS="$save_LIBS"
     fi