# HG changeset patch
# User Bruno Haible <bruno@clisp.org>
# Date 1318324559 -7200
# Node ID 4b3d35486c685cb59cdb4a9aab8f5fa98fc941cd
# Parent  617d0805c8d8d41bdd7b725d2252f331373ddc51
atanl: Simplify for platforms where 'long double' == 'double'.

* lib/atanl.c (atanl) [HAVE_SAME_LONG_DOUBLE_AS_DOUBLE]: New
alternative implementation.
* m4/atanl.m4 (gl_FUNC_ATANL): Require gl_LONG_DOUBLE_VS_DOUBLE.
Determine ATANL_LIBM according to HAVE_SAME_LONG_DOUBLE_AS_DOUBLE.
* modules/atanl (Depends-on): Add atan. Update conditions.

diff --git a/ChangeLog b/ChangeLog
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2011-10-10  Bruno Haible  <bruno@clisp.org>
+
+	atanl: Simplify for platforms where 'long double' == 'double'.
+	* lib/atanl.c (atanl) [HAVE_SAME_LONG_DOUBLE_AS_DOUBLE]: New
+	alternative implementation.
+	* m4/atanl.m4 (gl_FUNC_ATANL): Require gl_LONG_DOUBLE_VS_DOUBLE.
+	Determine ATANL_LIBM according to HAVE_SAME_LONG_DOUBLE_AS_DOUBLE.
+	* modules/atanl (Depends-on): Add atan. Update conditions.
+
 2011-10-10  Bruno Haible  <bruno@clisp.org>
 
 	acosl: Simplify for platforms where 'long double' == 'double'.
diff --git a/lib/atanl.c b/lib/atanl.c
--- a/lib/atanl.c
+++ b/lib/atanl.c
@@ -18,6 +18,16 @@
 /* Specification.  */
 #include <math.h>
 
+#if HAVE_SAME_LONG_DOUBLE_AS_DOUBLE
+
+long double
+atanl (long double x)
+{
+  return atan (x);
+}
+
+#else
+
 /*                                                      s_atanl.c
  *
  *      Inverse circular tangent for 128-bit long double precision
@@ -222,3 +232,5 @@
   else
     return u;
 }
+
+#endif
diff --git a/m4/atanl.m4 b/m4/atanl.m4
--- a/m4/atanl.m4
+++ b/m4/atanl.m4
@@ -1,4 +1,4 @@
-# atanl.m4 serial 5
+# atanl.m4 serial 6
 dnl Copyright (C) 2010-2011 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -7,6 +7,8 @@
 AC_DEFUN([gl_FUNC_ATANL],
 [
   AC_REQUIRE([gl_MATH_H_DEFAULTS])
+  AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
+
   dnl Persuade glibc <math.h> to declare atanl().
   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
 
@@ -56,12 +58,17 @@
     HAVE_DECL_ATANL=0
     HAVE_ATANL=0
     dnl Find libraries needed to link lib/atanl.c.
-    AC_REQUIRE([gl_FUNC_ISNANL])
-    dnl Append $ISNANL_LIBM to ATANL_LIBM, avoiding gratuitous duplicates.
-    case " $ATANL_LIBM " in
-      *" $ISNANL_LIBM "*) ;;
-      *) ATANL_LIBM="$ATANL_LIBM $ISNANL_LIBM" ;;
-    esac
+    if test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1; then
+      AC_REQUIRE([gl_FUNC_ATAN])
+      ATANL_LIBM="$ATAN_LIBM"
+    else
+      AC_REQUIRE([gl_FUNC_ISNANL])
+      dnl Append $ISNANL_LIBM to ATANL_LIBM, avoiding gratuitous duplicates.
+      case " $ATANL_LIBM " in
+        *" $ISNANL_LIBM "*) ;;
+        *) ATANL_LIBM="$ATANL_LIBM $ISNANL_LIBM" ;;
+      esac
+    fi
   fi
   AC_SUBST([ATANL_LIBM])
 ])
diff --git a/modules/atanl b/modules/atanl
--- a/modules/atanl
+++ b/modules/atanl
@@ -8,7 +8,8 @@
 Depends-on:
 math
 extensions
-isnanl          [test $HAVE_ATANL = 0]
+atan            [test $HAVE_ATANL = 0 && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1]
+isnanl          [test $HAVE_ATANL = 0 && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 
 configure.ac:
 gl_FUNC_ATANL