[PATCH] Remove redundant std::move on const object

[Jonathan Wakely]

This parameter is a reference-to-const so moving it doesn't do
anything. Allocators should be cheap to copy anyway.

	* include/bits/shared_ptr_base.h (__shared_count): Remove redundant
	move of const value.

Tested powerpc64le-linux, committed to trunk.


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commit 11b524858a52ef3f22b515c5a0320bbbae7be597
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Jun 6 15:54:01 2018 +0100

    Remove redundant std::move on const object
    
            * include/bits/shared_ptr_base.h (__shared_count): Remove redundant
            move of const value.

diff --git a/libstdc++-v3/include/bits/shared_ptr_base.h b/libstdc++-v3/include/bits/shared_ptr_base.h
index 6c5089afdda..887edbd7879 100644
--- a/libstdc++-v3/include/bits/shared_ptr_base.h
+++ b/libstdc++-v3/include/bits/shared_ptr_base.h
@@ -534,6 +534,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     public:
       using __allocator_type = __alloc_rebind<_Alloc, _Sp_counted_ptr_inplace>;
 
+      // Alloc parameter is not a reference so doesn't alias anything in __args
       template<typename... _Args>
 	_Sp_counted_ptr_inplace(_Alloc __a, _Args&&... __args)
 	: _M_impl(__a)
@@ -653,8 +654,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	  typename _Sp_cp_type::__allocator_type __a2(__a);
 	  auto __guard = std::__allocate_guarded(__a2);
 	  _Sp_cp_type* __mem = __guard.get();
-	  ::new (__mem) _Sp_cp_type(std::move(__a),
-				    std::forward<_Args>(__args)...);
+	  ::new (__mem) _Sp_cp_type(__a, std::forward<_Args>(__args)...);
 	  _M_pi = __mem;
 	  __guard = nullptr;
 	}