gcc/cp/

        PR c++/54537
        * cp-tree.h: Check OVL_USED with OVERLOAD_CHECK.
        * name-lookup.c (do_nonmember_using_decl): Make sure we have an
	OVERLOAD before calling OVL_USED. Call diagnose_name_conflict
	instead of issuing an error without mentioning the conflicting
	declaration.

libstdc++-v3/
        PR c++/54537
	* include/tr1/cmath: Remove pow(double,double) overload, remove a
	duplicated comment about DR 550. Add a comment to explain the
	issue.
	* testsuite/tr1/8_c_compatibility/cmath/pow_cmath.cc: New.

gcc/testsuite/
        PR c++/54537
        * g++.dg/overload/using3.C: New.
	* g++.dg/overload/using2.C: Adjust.
	* g++.dg/lookup/using9.C: Likewise.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@201414 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 12 insertions, 7 deletions

diff --git a/libstdc++-v3/include/tr1/cmath b/libstdc++-v3/include/tr1/cmath
index 3658afb1d64..6e63e56b45e 100644
--- a/libstdc++-v3/include/tr1/cmath
+++ b/libstdc++-v3/include/tr1/cmath
@@ -846,10 +846,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     nexttoward(_Tp __x, long double __y)
     { return __builtin_nexttoward(__x, __y); }
 
-  // DR 550. What should the return type of pow(float,int) be?
-  // NB: C++0x and TR1 != C++03.
-  //   using std::pow;
-
   inline float
   remainder(float __x, float __y)
   { return __builtin_remainderf(__x, __y); }
@@ -985,9 +981,18 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
   // DR 550. What should the return type of pow(float,int) be?
   // NB: C++0x and TR1 != C++03.
-  inline double
-  pow(double __x, double __y)
-  { return std::pow(__x, __y); }
+
+  // The std::tr1::pow(double, double) overload cannot be provided
+  // here, because it would clash with ::pow(double,double) declared
+  // in <math.h>, if <tr1/math.h> is included at the same time (raised
+  // by the fix of PR c++/54537). It is not possible either to use the
+  // using-declaration 'using ::pow;' here, because if the user code
+  // has a 'using std::pow;', it would bring the pow(*,int) averloads
+  // in the tr1 namespace, which is undesirable. Consequently, the
+  // solution is to forward std::tr1::pow(double,double) to
+  // std::pow(double,double) via the templatized version below. See
+  // the discussion about this issue here:
+  // http://gcc.gnu.org/ml/gcc-patches/2012-09/msg01278.html
 
   inline float
   pow(float __x, float __y)