[PATCH] D41992: [libcxx] Avoid spurious construction of valarray elements

2018-02-08 Thread Mikhail Maltsev via Phabricator via cfe-commits 
This revision was automatically updated to reflect the committed changes.
Closed by commit rCXX324596: [libcxx] Avoid spurious construction of valarray 
elements (authored by miyuki, committed by ).

Repository:
  rCXX libc++

https://reviews.llvm.org/D41992

Files:
  include/valarray
  
test/std/numerics/numarray/template.valarray/valarray.assign/copy_assign.pass.cpp
  
test/std/numerics/numarray/template.valarray/valarray.assign/initializer_list_assign.pass.cpp
  test/std/numerics/numarray/template.valarray/valarray.cons/default.pass.cpp
  test/std/numerics/numarray/template.valarray/valarray.cons/size.pass.cpp

Index: include/valarray
===
--- include/valarray
+++ include/valarray
@@ -1053,6 +1053,9 @@
 friend
 const _Up*
 end(const valarray<_Up>& __v);
+
+void __clear();
+valarray& __assign_range(const value_type* __f, const value_type* __l);
 };
 
 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS valarray::valarray(size_t))
@@ -2750,7 +2753,24 @@
 : __begin_(0),
   __end_(0)
 {
-resize(__n);
+if (__n)
+{
+__begin_ = __end_ = static_cast(_VSTD::__allocate(__n * sizeof(value_type)));
+#ifndef _LIBCPP_NO_EXCEPTIONS
+try
+{
+#endif  // _LIBCPP_NO_EXCEPTIONS
+for (; __n; --__n, ++__end_)
+::new (__end_) value_type();
+#ifndef _LIBCPP_NO_EXCEPTIONS
+}
+catch (...)
+{
+__clear();
+throw;
+}
+#endif  // _LIBCPP_NO_EXCEPTIONS
+}
 }
 
 template 
@@ -2780,7 +2800,7 @@
 }
 catch (...)
 {
-resize(0);
+__clear();
 throw;
 }
 #endif  // _LIBCPP_NO_EXCEPTIONS
@@ -2805,7 +2825,7 @@
 }
 catch (...)
 {
-resize(0);
+__clear();
 throw;
 }
 #endif  // _LIBCPP_NO_EXCEPTIONS
@@ -2842,7 +2862,7 @@
 }
 catch (...)
 {
-resize(0);
+__clear();
 throw;
 }
 #endif  // _LIBCPP_NO_EXCEPTIONS
@@ -2870,7 +2890,7 @@
 }
 catch (...)
 {
-resize(0);
+__clear();
 throw;
 }
 #endif  // _LIBCPP_NO_EXCEPTIONS
@@ -2899,7 +2919,7 @@
 }
 catch (...)
 {
-resize(0);
+__clear();
 throw;
 }
 #endif  // _LIBCPP_NO_EXCEPTIONS
@@ -2928,7 +2948,7 @@
 }
 catch (...)
 {
-resize(0);
+__clear();
 throw;
 }
 #endif  // _LIBCPP_NO_EXCEPTIONS
@@ -2957,7 +2977,7 @@
 }
 catch (...)
 {
-resize(0);
+__clear();
 throw;
 }
 #endif  // _LIBCPP_NO_EXCEPTIONS
@@ -2968,30 +2988,43 @@
 inline
 valarray<_Tp>::~valarray()
 {
-resize(0);
+__clear();
 }
 
 template 
 valarray<_Tp>&
-valarray<_Tp>::operator=(const valarray& __v)
+valarray<_Tp>::__assign_range(const value_type* __f, const value_type* __l)
 {
-if (this != &__v)
+size_t __n = __l - __f;
+if (size() != __n)
 {
-if (size() != __v.size())
-resize(__v.size());
-_VSTD::copy(__v.__begin_, __v.__end_, __begin_);
+__clear();
+__begin_ = static_cast(_VSTD::__allocate(__n * sizeof(value_type)));
+__end_ = __begin_ + __n;
+_VSTD::uninitialized_copy(__f, __l, __begin_);
+} else {
+_VSTD::copy(__f, __l, __begin_);
 }
 return *this;
 }
 
+template 
+valarray<_Tp>&
+valarray<_Tp>::operator=(const valarray& __v)
+{
+if (this != &__v)
+return __assign_range(__v.__begin_, __v.__end_);
+return *this;
+}
+
 #ifndef _LIBCPP_CXX03_LANG
 
 template 
 inline
 valarray<_Tp>&
 valarray<_Tp>::operator=(valarray&& __v) _NOEXCEPT
 {
-resize(0);
+__clear();
 __begin_ = __v.__begin_;
 __end_ = __v.__end_;
 __v.__begin_ = nullptr;
@@ -3004,10 +3037,7 @@
 valarray<_Tp>&
 valarray<_Tp>::operator=(initializer_list __il)
 {
-if (size() != __il.size())
-resize(__il.size());
-_VSTD::copy(__il.begin(), __il.end(), __begin_);
-return *this;
+return __assign_range(__il.begin(), __il.end());
 }
 
 #endif  // _LIBCPP_CXX03_LANG
@@ -3680,15 +3710,22 @@
 
 template 
 void
-valarray<_Tp>::resize(size_t __n, value_type __x)
+valarray<_Tp>::__clear()
 {
 if (__begin_ != nullptr)
 {
 while (__end_ != __begin_)
 (--__end_)->~value_type();
 _VSTD::__libcpp_deallocate(__begin_);
 __begin_ = __end_ = nullptr;
 }
+}
+
+template 
+void
+valarray<_Tp>::resize(size_t __n, value_type __x)
+{
+__clear();
 if (__n)
 {
 __begin_ = __end_ = static_cast(_VSTD::__allocate(__n * sizeof(value_type)));
@@ -3702,7 +3739,7 @@
 }
 catch (...)
 {
-resize(0);
+__clear();
 throw;
 }
 #endif  // _LIBCPP_NO_EXCEPTIONS
Inde

[PATCH] D41992: [libcxx] Avoid spurious construction of valarray elements

2018-02-07 Thread Marshall Clow via Phabricator via cfe-commits 
mclow.lists accepted this revision.
mclow.lists added a comment.
This revision is now accepted and ready to land.

This LGTM.




Comment at: include/valarray:3728
+{
+__clear();
 if (__n)

I thought that you had lost an exception guarantee here, but it turns out that 
there wasn't one before.  If the allocation fails, you are left with an empty 
array instead of the old contents.




https://reviews.llvm.org/D41992



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[PATCH] D41992: [libcxx] Avoid spurious construction of valarray elements

2018-02-06 Thread Mikhail Maltsev via Phabricator via cfe-commits 
miyuki added a comment.

ping^3


https://reviews.llvm.org/D41992



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[PATCH] D41992: [libcxx] Avoid spurious construction of valarray elements

2018-01-26 Thread Mikhail Maltsev via Phabricator via cfe-commits 
miyuki added a comment.

ping^2


https://reviews.llvm.org/D41992



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[PATCH] D41992: [libcxx] Avoid spurious construction of valarray elements

2018-01-19 Thread Mikhail Maltsev via Phabricator via cfe-commits 
miyuki added a comment.

ping


https://reviews.llvm.org/D41992



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[PATCH] D41992: [libcxx] Avoid spurious construction of valarray elements

2018-01-12 Thread Mikhail Maltsev via Phabricator via cfe-commits 
miyuki created this revision.
miyuki added reviewers: EricWF, mclow.lists.

Currently libc++ implements some operations on valarray by using the
resize method. This method has a parameter with a default value.
Because of this, valarray may spuriously construct and destruct
objects of valarray's element type.

  

This patch fixes this issue and adds corresponding test cases.


https://reviews.llvm.org/D41992

Files:
  include/valarray
  
test/std/numerics/numarray/template.valarray/valarray.assign/copy_assign.pass.cpp
  
test/std/numerics/numarray/template.valarray/valarray.assign/initializer_list_assign.pass.cpp
  test/std/numerics/numarray/template.valarray/valarray.cons/default.pass.cpp
  test/std/numerics/numarray/template.valarray/valarray.cons/size.pass.cpp

Index: test/std/numerics/numarray/template.valarray/valarray.cons/size.pass.cpp
===
--- test/std/numerics/numarray/template.valarray/valarray.cons/size.pass.cpp
+++ test/std/numerics/numarray/template.valarray/valarray.cons/size.pass.cpp
@@ -16,6 +16,15 @@
 #include 
 #include 
 
+struct S {
+S() : x(1) {}
+~S() { ++cnt_dtor; }
+int x;
+static size_t cnt_dtor;
+};
+
+size_t S::cnt_dtor = 0;
+
 int main()
 {
 {
@@ -36,4 +45,11 @@
 for (int i = 0; i < 100; ++i)
 assert(v[i].size() == 0);
 }
+{
+std::valarray v(100);
+assert(v.size() == 100);
+for (int i = 0; i < 100; ++i)
+assert(v[i].x == 1);
+}
+assert(S::cnt_dtor == 100);
 }
Index: test/std/numerics/numarray/template.valarray/valarray.cons/default.pass.cpp
===
--- test/std/numerics/numarray/template.valarray/valarray.cons/default.pass.cpp
+++ test/std/numerics/numarray/template.valarray/valarray.cons/default.pass.cpp
@@ -16,6 +16,13 @@
 #include 
 #include 
 
+struct S {
+S() { ctor_called = true; }
+static bool ctor_called;
+};
+
+bool S::ctor_called = false;
+
 int main()
 {
 {
@@ -34,4 +41,9 @@
 std::valarray > v;
 assert(v.size() == 0);
 }
+{
+std::valarray v;
+assert(v.size() == 0);
+assert(!S::ctor_called);
+}
 }
Index: test/std/numerics/numarray/template.valarray/valarray.assign/initializer_list_assign.pass.cpp
===
--- test/std/numerics/numarray/template.valarray/valarray.assign/initializer_list_assign.pass.cpp
+++ test/std/numerics/numarray/template.valarray/valarray.assign/initializer_list_assign.pass.cpp
@@ -19,6 +19,21 @@
 #include 
 #include 
 
+struct S
+{
+S() : x_(0) { default_ctor_called = true; }
+S(int x) : x_(x) {}
+int x_;
+static bool default_ctor_called;
+};
+
+bool S::default_ctor_called = false;
+
+bool operator==(const S& lhs, const S& rhs)
+{
+return lhs.x_ == rhs.x_;
+}
+
 int main()
 {
 {
@@ -55,4 +70,15 @@
 assert(v2[i][j] == a[i][j]);
 }
 }
+{
+typedef S T;
+T a[] = {T(1), T(2), T(3), T(4), T(5)};
+const unsigned N = sizeof(a)/sizeof(a[0]);
+std::valarray v2;
+v2 = {T(1), T(2), T(3), T(4), T(5)};
+assert(v2.size() == N);
+for (std::size_t i = 0; i < v2.size(); ++i)
+assert(v2[i] == a[i]);
+assert(!S::default_ctor_called);
+}
 }
Index: test/std/numerics/numarray/template.valarray/valarray.assign/copy_assign.pass.cpp
===
--- test/std/numerics/numarray/template.valarray/valarray.assign/copy_assign.pass.cpp
+++ test/std/numerics/numarray/template.valarray/valarray.assign/copy_assign.pass.cpp
@@ -17,6 +17,21 @@
 #include 
 #include 
 
+struct S
+{
+S() : x_(0) { default_ctor_called = true; }
+S(int x) : x_(x) {}
+int x_;
+static bool default_ctor_called;
+};
+
+bool S::default_ctor_called = false;
+
+bool operator==(const S& lhs, const S& rhs)
+{
+return lhs.x_ == rhs.x_;
+}
+
 int main()
 {
 {
@@ -56,4 +71,16 @@
 assert(v2[i][j] == v[i][j]);
 }
 }
+{
+typedef S T;
+T a[] = {T(1), T(2), T(3), T(4), T(5)};
+const unsigned N = sizeof(a)/sizeof(a[0]);
+std::valarray v(a, N);
+std::valarray v2;
+v2 = v;
+assert(v2.size() == v.size());
+for (std::size_t i = 0; i < v2.size(); ++i)
+assert(v2[i] == v[i]);
+assert(!S::default_ctor_called);
+}
 }
Index: include/valarray
===
--- include/valarray
+++ include/valarray
@@ -1053,6 +1053,9 @@
 friend
 const _Up*
 end(const valarray<_Up>& __v);
+
+void __clear();
+valarray& __assign_range(const value_type* __f, const value_type* __l);
 };
 
 _LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS valarray::valarray(size_t))
@@ -2750,7 +2753,24 @@
 : __begin_(0),
   __end_(0)
 {