X-Git-Url: https://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Fhypotf.m4;h=aec739b085c85621c890e4bbb6cc0a8fae93f973;hb=da8054d48dc22e1c051db54049e005d51a006e69;hp=fd1b1ebf0e0558ba7299c3bd9fc817a2b8133688;hpb=43d9445417406daf7f20d78abc21725af2be1457;p=gnulib.git

diff --git a/m4/hypotf.m4 b/m4/hypotf.m4
index fd1b1ebf0..aec739b08 100644
--- a/m4/hypotf.m4
+++ b/m4/hypotf.m4
@@ -1,14 +1,18 @@
-# hypotf.m4 serial 1
-dnl Copyright (C) 2012 Free Software Foundation, Inc.
+# hypotf.m4 serial 4
+dnl Copyright (C) 2012-2013 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_HYPOTF],
 [
+  m4_divert_text([DEFAULTS], [gl_hypotf_required=plain])
   AC_REQUIRE([gl_MATH_H_DEFAULTS])
   AC_REQUIRE([gl_FUNC_HYPOT])
 
+  dnl Persuade glibc <math.h> to declare hypotf().
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
   dnl Test whether hypotf() exists. Assume that hypotf(), if it exists, is
   dnl defined in the same library as hypot().
   save_LIBS="$LIBS"
@@ -25,6 +29,60 @@ AC_DEFUN([gl_FUNC_HYPOTF],
       *yes) ;;
       *) REPLACE_HYPOTF=1 ;;
     esac
+    m4_ifdef([gl_FUNC_HYPOTF_IEEE], [
+      if test $gl_hypotf_required = ieee && test $REPLACE_HYPOTF = 0; then
+        AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+        AC_CACHE_CHECK([whether hypotf works according to ISO C 99 with IEC 60559],
+          [gl_cv_func_hypotf_ieee],
+          [
+            save_LIBS="$LIBS"
+            LIBS="$LIBS $HYPOTF_LIBM"
+            AC_RUN_IFELSE(
+              [AC_LANG_SOURCE([[
+#ifndef __NO_MATH_INLINES
+# define __NO_MATH_INLINES 1 /* for glibc */
+#endif
+#include <math.h>
+/* Compare two numbers with ==.
+   This is a separate function because IRIX 6.5 "cc -O" miscompiles an
+   'x == x' test.  */
+static int
+numeric_equal (float x, float y)
+{
+  return x == y;
+}
+static float dummy (float x, float y) { return 0; }
+float zero;
+float one = 1.0f;
+int main (int argc, char *argv[])
+{
+  float (*my_hypotf) (float, float) = argc ? hypotf : dummy;
+  float f;
+  /* Test hypotf(NaN,Infinity).
+     This test fails on OSF/1 5.1 and native Windows.  */
+  f = my_hypotf (zero / zero, one / zero);
+  if (!numeric_equal (f, f))
+    return 1;
+  return 0;
+}
+              ]])],
+              [gl_cv_func_hypotf_ieee=yes],
+              [gl_cv_func_hypotf_ieee=no],
+              [case "$host_os" in
+                         # Guess yes on glibc systems.
+                 *-gnu*) gl_cv_func_hypotf_ieee="guessing yes" ;;
+                         # If we don't know, assume the worst.
+                 *)      gl_cv_func_hypotf_ieee="guessing no" ;;
+               esac
+              ])
+            LIBS="$save_LIBS"
+          ])
+        case "$gl_cv_func_hypotf_ieee" in
+          *yes) ;;
+          *) REPLACE_HYPOTF=1 ;;
+        esac
+      fi
+    ])
   else
     HAVE_HYPOTF=0
   fi