re PR libstdc++/11706 (std::pow(T, int) implementation pessimizes code)

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.

Co-Authored-By: Paolo Carlini <pcarlini@suse.de>
From-SVN: r94982

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 27bf800347782f598d6f22f44be4e6af1078936e..6d3eea2887d762f08a81a4bdda72d7fe1820defa 100644 (file)
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,12 @@
+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.
+
 2005-02-11  Janis Johnson  <janis187@us.ibm.com>
 
        * testsuite/26_numerics/complex/13450.cc: Fix XFAIL selector.

diff --git a/libstdc++-v3/include/c_std/std_cmath.h b/libstdc++-v3/include/c_std/std_cmath.h
index 5aefe0ff8ac6c925d93162d20396cb7c9e49e517..1dd6c732ab1d59c85d323def13d817a459d747c5 100644 (file)
--- a/libstdc++-v3/include/c_std/std_cmath.h
+++ b/libstdc++-v3/include/c_std/std_cmath.h
@@ -350,15 +350,15 @@ namespace std
 
   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 --git a/libstdc++-v3/testsuite/26_numerics/cmath/powi.cc b/libstdc++-v3/testsuite/26_numerics/cmath/powi.cc
new file mode 100644 (file)
index 0000000..588448c
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/cmath/powi.cc
@@ -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;
+}