[Patch] libstdc++/11706

[Paolo Carlini <pcarlini at suse dot de>]

Hi,

finally we have both the appropriate integer power builtins and the
basic folding in place, and seems safe and convenient to switch the
library to use the infrastructure.

Indeed, I regtested succesfully the below - which includes a basic
sanity check, adding to the existing compiler-side tests - on
x86/x86_64/ia64-linux.

I'll wait 'til tomorrow in case of issues.

Thanks,
Paolo.

//////////////
2005-02-13  Richard Guenther  <rguenth@gcc.gnu.org>
	    Paolo Carlini  <pcarlini@suse.de>

	PR libstdc++/11706
	* include/c_std/std_cmath.h (pow): Use __builtin_powi[lf]
	for integer overloads.

	* testsuite/26_numerics/cmath/powi.cc: New.

diff -urN libstdc++-v3-orig/include/c_std/std_cmath.h libstdc++-v3/include/c_std/std_cmath.h
--- libstdc++-v3-orig/include/c_std/std_cmath.h	2005-02-01 14:30:32.000000000 +0100
+++ libstdc++-v3/include/c_std/std_cmath.h	2005-02-12 21:24:17.000000000 +0100
@@ -350,15 +350,15 @@
 
   inline double
   pow(double __x, int __i)
-  { return __pow_helper(__x, __i); }
+  { return __builtin_powi(__x, __i); }
 
   inline float
   pow(float __x, int __n)
-  { return __pow_helper(__x, __n); }
+  { return __builtin_powif(__x, __n); }
 
   inline long double
   pow(long double __x, int __n)
-  { return __pow_helper(__x, __n); }
+  { return __builtin_powil(__x, __n); }
 
   using ::sin;
 
diff -urN libstdc++-v3-orig/testsuite/26_numerics/cmath/powi.cc libstdc++-v3/testsuite/26_numerics/cmath/powi.cc
--- libstdc++-v3-orig/testsuite/26_numerics/cmath/powi.cc	1970-01-01 01:00:00.000000000 +0100
+++ libstdc++-v3/testsuite/26_numerics/cmath/powi.cc	2005-02-12 21:32:05.000000000 +0100
@@ -0,0 +1,64 @@
+// 2005-02-13  Paolo Carlini  <pcarlini@suse.de>
+
+// Copyright (C) 2005 Free Software Foundation
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 2, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING.  If not, write to the Free
+// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
+// USA.
+
+// 26.5 C Library
+
+#include <cmath>
+#include <testsuite_hooks.h>
+
+template<typename T>
+  void test01_do()
+  {
+    using namespace std;
+    bool test __attribute__((unused)) = true;
+    
+    VERIFY( pow(T(1.0), 0) == T(1.0) );
+    VERIFY( pow(T(2.0), 0) == T(1.0) );
+    VERIFY( pow(T(-1.0), 0) == T(1.0) );
+    VERIFY( pow(T(-4.0), 0) == T(1.0) );
+
+    VERIFY( pow(T(1.0), 1) == T(1.0) );
+    VERIFY( pow(T(2.0), 1) == T(2.0) );
+    VERIFY( pow(T(-1.0), 1) == T(-1.0) );
+    VERIFY( pow(T(-4.0), 1) == T(-4.0) );
+
+    VERIFY( pow(T(1.0), -1) == T(1.0) / T(1.0) );
+    VERIFY( pow(T(2.0), -1) == T(1.0) / T(2.0) );
+    VERIFY( pow(T(-1.0), -1) == T(1.0) / T(-1.0) );
+    VERIFY( pow(T(-4.0), -1) == T(1.0) / T(-4.0) );
+
+    VERIFY( pow(T(1.0), 2) == T(1.0) * T(1.0) );
+    VERIFY( pow(T(2.0), 2) == T(2.0) * T(2.0) );
+    VERIFY( pow(T(-1.0), 2) == T(-1.0) * T(-1.0) );
+    VERIFY( pow(T(-4.0), 2) == T(-4.0) * T(-4.0) );
+  }
+
+void test01()
+{
+  test01_do<float>();
+  test01_do<double>();
+  test01_do<long double>();
+}
+
+int main()
+{
+  test01();
+  return 0;
+}