X-Git-Url: https://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Froundf.m4;h=b1c4787e048ca129a46c8d99bc4457d2cb10f1be;hb=ba3be00a5546579e80323430a57a3aedaedc6156;hp=d1f4183760ab6954db6f35c1ce1c27dc9c8bdffa;hpb=7094a1e0d56aa303077cc0bccaa559a28e613ade;p=gnulib.git

diff --git a/m4/roundf.m4 b/m4/roundf.m4
index d1f418376..b1c4787e0 100644
--- a/m4/roundf.m4
+++ b/m4/roundf.m4
@@ -1,28 +1,155 @@
-# roundf.m4 serial 2
-dnl Copyright (C) 2007 Free Software Foundation, Inc.
+# roundf.m4 serial 17
+dnl Copyright (C) 2007-2012 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 "$ac_cv_have_decl_roundf" = yes; then
-    gl_CHECK_MATH_LIB([ROUNDF_LIBM], [x = roundf (x);])
+
+  gl_CHECK_MATH_LIB([ROUNDF_LIBM], [x = roundf (x);],
+    [extern
+     #ifdef __cplusplus
+     "C"
+     #endif
+     float roundf (float);
+    ])
+  if test "$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])
+    AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+    AC_CACHE_CHECK([whether roundf works], [gl_cv_func_roundf_works],
+      [
+        save_LIBS="$LIBS"
+        LIBS="$LIBS $ROUNDF_LIBM"
+        AC_RUN_IFELSE([AC_LANG_SOURCE([[
+#include <float.h>
+#include <math.h>
+extern
+#ifdef __cplusplus
+"C"
+#endif
+float roundf (float);
+#ifdef _MSC_VER
+# pragma fenv_access (off)
+#endif
+int main()
+{
+  /* 2^FLT_MANT_DIG.  */
+  static const float TWO_MANT_DIG =
+    /* Assume FLT_MANT_DIG <= 3 * 31.
+       Use the identity  n = floor(n/3) + floor((n+1)/3) + floor((n+2)/3).  */
+    (float) (1U << (FLT_MANT_DIG / 3))
+    * (float) (1U << ((FLT_MANT_DIG + 1) / 3))
+    * (float) (1U << ((FLT_MANT_DIG + 2) / 3));
+  volatile float x = 0.5f - 0.5f / TWO_MANT_DIG;
+  exit (x < 0.5f && roundf (x) != 0.0f);
+}]])], [gl_cv_func_roundf_works=yes], [gl_cv_func_roundf_works=no],
+        [case "$host_os" in
+           mingw*) gl_cv_func_roundf_works="guessing no";;
+           *)      gl_cv_func_roundf_works="guessing yes";;
+         esac
+        ])
+        LIBS="$save_LIBS"
+      ])
+    case "$gl_cv_func_roundf_works" in
+      *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
-    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_CHECK_MATH_LIB([ROUNDF_LIBM], [x = floorf (x) + ceilf (x);])
+    HAVE_ROUNDF=0
+    HAVE_DECL_ROUNDF=0
+  fi
+  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 "$ac_cv_have_decl_ceilf" = yes; then
+      gl_FUNC_FLOORF_LIBS
+      gl_FUNC_CEILF_LIBS
+      if test "$FLOORF_LIBM" != '?' && test "$CEILF_LIBM" != '?'; then
+        AC_DEFINE([HAVE_FLOORF_AND_CEILF], [1],
+          [Define if the both the floorf() and ceilf() functions exist.])
+        ROUNDF_LIBM=
+        dnl Append $FLOORF_LIBM to ROUNDF_LIBM, avoiding gratuitous duplicates.
+        case " $ROUNDF_LIBM " in
+          *" $FLOORF_LIBM "*) ;;
+          *) ROUNDF_LIBM="$ROUNDF_LIBM $FLOORF_LIBM" ;;
+        esac
+        dnl Append $CEILF_LIBM to ROUNDF_LIBM, avoiding gratuitous duplicates.
+        case " $ROUNDF_LIBM " in
+          *" $CEILF_LIBM "*) ;;
+          *) ROUNDF_LIBM="$ROUNDF_LIBM $CEILF_LIBM" ;;
+        esac
+      else
+        ROUNDF_LIBM=
+      fi
     else
       ROUNDF_LIBM=
     fi
-    HAVE_DECL_ROUNDF=0
-    AC_LIBOBJ([roundf])
   fi
-  AC_SUBST([HAVE_DECL_ROUNDF])
   AC_SUBST([ROUNDF_LIBM])
 ])