From 1db0418ae570eff510bb0c52cb5dbed54320d5a4 Mon Sep 17 00:00:00 2001
From: Gabriel Dos Reis <gdr@integrable-solutions.net>
Date: Tue, 20 May 2003 06:52:11 +0000
Subject: [PATCH] re PR libstdc++/10689 (pow(std::complex(0),1/3) returns (nan,
 nan) instead of 0.)

	PR libstdc++/10689
	* include/std/std_complex.h (pow): Tidy

From-SVN: r66989
---
 libstdc++-v3/ChangeLog                           |  5 +++++
 libstdc++-v3/include/std/std_complex.h           | 14 ++++++++++----
 libstdc++-v3/testsuite/26_numerics/complex/pow.C | 14 ++++++++++++++
 3 files changed, 29 insertions(+), 4 deletions(-)
 create mode 100644 libstdc++-v3/testsuite/26_numerics/complex/pow.C

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 6fc5fe7205c..6f3c11083b0 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,8 @@
+2003-05-20  Gabriel Dos Reis <gdr@integrable-solutions.net>
+
+	PR libstdc++/10689
+	* include/std/std_complex.h (pow): Tidy.
+	
 2003-05-19  Paolo Carlini  <pcarlini@unitus.it>
 
 	* testsuite/27_io/basic_filebuf/close/char/4.cc: New file, testing
diff --git a/libstdc++-v3/include/std/std_complex.h b/libstdc++-v3/include/std/std_complex.h
index 87e4bcb4d26..e943f5edcee 100644
--- a/libstdc++-v3/include/std/std_complex.h
+++ b/libstdc++-v3/include/std/std_complex.h
@@ -565,24 +565,30 @@ namespace std
     }
 
   template<typename _Tp>
-    inline complex<_Tp>
+    complex<_Tp>
     pow(const complex<_Tp>& __x, const _Tp& __y)
     {
-      return exp(__y * log(__x));
+      if (__x.imag() == _Tp())
+        return pow(__x.real(), __y);
+
+      complex<_Tp> __t = log(__x);
+      return polar(exp(__y * __t.real()), __y * __t.imag());
     }
 
   template<typename _Tp>
     inline complex<_Tp>
     pow(const complex<_Tp>& __x, const complex<_Tp>& __y)
     {
-      return exp(__y * log(__x));
+      return __x == _Tp() ? _Tp() : exp(__y * log(__x));
     }
 
   template<typename _Tp>
     inline complex<_Tp>
     pow(const _Tp& __x, const complex<_Tp>& __y)
     {
-      return exp(__y * log(__x));
+      return __x == _Tp()
+        ? _Tp()
+        : polar(pow(__x, __y.real()), __y.imag() * log(__x));
     }
 
   // 26.2.3  complex specializations
diff --git a/libstdc++-v3/testsuite/26_numerics/complex/pow.C b/libstdc++-v3/testsuite/26_numerics/complex/pow.C
new file mode 100644
index 00000000000..c3f8479828d
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/complex/pow.C
@@ -0,0 +1,14 @@
+// PR libbstdc++/10689
+// Origin: Daniel.Levine@jhuaph.edu
+
+#include <complex>
+#include <testsuite_hooks.h>
+
+int main()
+{
+   std::complex<double> z(0, 1) ;
+
+   VERIFY(pow(z, 1.0/3.0) == 0.0);
+
+   return 0;
+}
-- 
2.30.2