X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=blobdiff_plain;f=include%2Fllvm%2FADT%2FSmallVector.h;h=c9ddf61f5e802b9930065276540e1e77abc42a7d;hp=973e0284ab0694800473a1eaf39222d9afafd947;hb=36013dd6a10ace0459bd9a2623cdb548b58be1d1;hpb=38dbb606755232e229f11994fc2bbf10e8c5788b

diff --git a/include/llvm/ADT/SmallVector.h b/include/llvm/ADT/SmallVector.h
index 973e0284ab0..c9ddf61f5e8 100644
--- a/include/llvm/ADT/SmallVector.h
+++ b/include/llvm/ADT/SmallVector.h
@@ -14,7 +14,10 @@
 #ifndef LLVM_ADT_SMALLVECTOR_H
 #define LLVM_ADT_SMALLVECTOR_H
 
+#include "llvm/ADT/iterator_range.h"
+#include "llvm/Support/AlignOf.h"
 #include "llvm/Support/Compiler.h"
+#include "llvm/Support/MathExtras.h"
 #include "llvm/Support/type_traits.h"
 #include <algorithm>
 #include <cassert>
@@ -26,63 +29,67 @@
 
 namespace llvm {
 
-/// SmallVectorBase - This is all the non-templated stuff common to all
-/// SmallVectors.
+/// This is all the non-templated stuff common to all SmallVectors.
 class SmallVectorBase {
 protected:
   void *BeginX, *EndX, *CapacityX;
 
-  // Allocate raw space for N elements of type T.  If T has a ctor or dtor, we
-  // don't want it to be automatically run, so we need to represent the space as
-  // something else.  An array of char would work great, but might not be
-  // aligned sufficiently.  Instead we use some number of union instances for
-  // the space, which guarantee maximal alignment.
-  union U {
-    double D;
-    long double LD;
-    long long L;
-    void *P;
-  } FirstEl;
-  // Space after 'FirstEl' is clobbered, do not add any instance vars after it.
-
 protected:
-  SmallVectorBase(size_t Size)
-    : BeginX(&FirstEl), EndX(&FirstEl), CapacityX((char*)&FirstEl+Size) {}
-
-  /// isSmall - Return true if this is a smallvector which has not had dynamic
-  /// memory allocated for it.
-  bool isSmall() const {
-    return BeginX == static_cast<const void*>(&FirstEl);
-  }
+  SmallVectorBase(void *FirstEl, size_t Size)
+    : BeginX(FirstEl), EndX(FirstEl), CapacityX((char*)FirstEl+Size) {}
 
-  /// resetToSmall - Put this vector in a state of being small.
-  void resetToSmall() {
-    BeginX = EndX = CapacityX = &FirstEl;
-  }
-
-  /// grow_pod - This is an implementation of the grow() method which only works
+  /// This is an implementation of the grow() method which only works
   /// on POD-like data types and is out of line to reduce code duplication.
-  void grow_pod(size_t MinSizeInBytes, size_t TSize);
+  void grow_pod(void *FirstEl, size_t MinSizeInBytes, size_t TSize);
 
 public:
-  /// size_in_bytes - This returns size()*sizeof(T).
+  /// This returns size()*sizeof(T).
   size_t size_in_bytes() const {
     return size_t((char*)EndX - (char*)BeginX);
   }
-  
+
   /// capacity_in_bytes - This returns capacity()*sizeof(T).
   size_t capacity_in_bytes() const {
     return size_t((char*)CapacityX - (char*)BeginX);
   }
 
-  bool empty() const { return BeginX == EndX; }
+  bool LLVM_ATTRIBUTE_UNUSED_RESULT empty() const { return BeginX == EndX; }
 };
 
+template <typename T, unsigned N> struct SmallVectorStorage;
 
-template <typename T>
+/// This is the part of SmallVectorTemplateBase which does not depend on whether
+/// the type T is a POD. The extra dummy template argument is used by ArrayRef
+/// to avoid unnecessarily requiring T to be complete.
+template <typename T, typename = void>
 class SmallVectorTemplateCommon : public SmallVectorBase {
+private:
+  template <typename, unsigned> friend struct SmallVectorStorage;
+
+  // Allocate raw space for N elements of type T.  If T has a ctor or dtor, we
+  // don't want it to be automatically run, so we need to represent the space as
+  // something else.  Use an array of char of sufficient alignment.
+  typedef llvm::AlignedCharArrayUnion<T> U;
+  U FirstEl;
+  // Space after 'FirstEl' is clobbered, do not add any instance vars after it.
+
 protected:
-  SmallVectorTemplateCommon(size_t Size) : SmallVectorBase(Size) {}
+  SmallVectorTemplateCommon(size_t Size) : SmallVectorBase(&FirstEl, Size) {}
+
+  void grow_pod(size_t MinSizeInBytes, size_t TSize) {
+    SmallVectorBase::grow_pod(&FirstEl, MinSizeInBytes, TSize);
+  }
+
+  /// Return true if this is a smallvector which has not had dynamic
+  /// memory allocated for it.
+  bool isSmall() const {
+    return BeginX == static_cast<const void*>(&FirstEl);
+  }
+
+  /// Put this vector in a state of being small.
+  void resetToSmall() {
+    BeginX = EndX = CapacityX = &FirstEl;
+  }
 
   void setEnd(T *P) { this->EndX = P; }
 public:
@@ -119,35 +126,38 @@ public:
   size_type size() const { return end()-begin(); }
   size_type max_size() const { return size_type(-1) / sizeof(T); }
 
-  /// capacity - Return the total number of elements in the currently allocated
-  /// buffer.
+  /// Return the total number of elements in the currently allocated buffer.
   size_t capacity() const { return capacity_ptr() - begin(); }
 
-  /// data - Return a pointer to the vector's buffer, even if empty().
+  /// Return a pointer to the vector's buffer, even if empty().
   pointer data() { return pointer(begin()); }
-  /// data - Return a pointer to the vector's buffer, even if empty().
+  /// Return a pointer to the vector's buffer, even if empty().
   const_pointer data() const { return const_pointer(begin()); }
 
-  reference operator[](unsigned idx) {
-    assert(begin() + idx < end());
+  reference operator[](size_type idx) {
+    assert(idx < size());
     return begin()[idx];
   }
-  const_reference operator[](unsigned idx) const {
-    assert(begin() + idx < end());
+  const_reference operator[](size_type idx) const {
+    assert(idx < size());
     return begin()[idx];
   }
 
   reference front() {
+    assert(!empty());
     return begin()[0];
   }
   const_reference front() const {
+    assert(!empty());
     return begin()[0];
   }
 
   reference back() {
+    assert(!empty());
     return end()[-1];
   }
   const_reference back() const {
+    assert(!empty());
     return end()[-1];
   }
 };
@@ -166,85 +176,62 @@ protected:
     }
   }
 
-  /// move - Use move-assignment to move the range [I, E) onto the
+  /// Use move-assignment to move the range [I, E) onto the
   /// objects starting with "Dest".  This is just <memory>'s
   /// std::move, but not all stdlibs actually provide that.
   template<typename It1, typename It2>
   static It2 move(It1 I, It1 E, It2 Dest) {
-#if LLVM_USE_RVALUE_REFERENCES
     for (; I != E; ++I, ++Dest)
       *Dest = ::std::move(*I);
     return Dest;
-#else
-    return ::std::copy(I, E, Dest);
-#endif
   }
 
-  /// move_backward - Use move-assignment to move the range
+  /// Use move-assignment to move the range
   /// [I, E) onto the objects ending at "Dest", moving objects
   /// in reverse order.  This is just <algorithm>'s
   /// std::move_backward, but not all stdlibs actually provide that.
   template<typename It1, typename It2>
   static It2 move_backward(It1 I, It1 E, It2 Dest) {
-#if LLVM_USE_RVALUE_REFERENCES
     while (I != E)
       *--Dest = ::std::move(*--E);
     return Dest;
-#else
-    return ::std::copy_backward(I, E, Dest);
-#endif
   }
 
-  /// uninitialized_move - Move the range [I, E) into the uninitialized
-  /// memory starting with "Dest", constructing elements as needed.
+  /// Move the range [I, E) into the uninitialized memory starting with "Dest",
+  /// constructing elements as needed.
   template<typename It1, typename It2>
   static void uninitialized_move(It1 I, It1 E, It2 Dest) {
-#if LLVM_USE_RVALUE_REFERENCES
     for (; I != E; ++I, ++Dest)
       ::new ((void*) &*Dest) T(::std::move(*I));
-#else
-    ::std::uninitialized_copy(I, E, Dest);
-#endif
   }
 
-  /// uninitialized_copy - Copy the range [I, E) onto the uninitialized
-  /// memory starting with "Dest", constructing elements as needed.
+  /// Copy the range [I, E) onto the uninitialized memory starting with "Dest",
+  /// constructing elements as needed.
   template<typename It1, typename It2>
   static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
     std::uninitialized_copy(I, E, Dest);
   }
 
-  /// grow - Grow the allocated memory (without initializing new
-  /// elements), doubling the size of the allocated memory.
-  /// Guarantees space for at least one more element, or MinSize more
-  /// elements if specified.
+  /// Grow the allocated memory (without initializing new elements), doubling
+  /// the size of the allocated memory. Guarantees space for at least one more
+  /// element, or MinSize more elements if specified.
   void grow(size_t MinSize = 0);
-  
+
 public:
   void push_back(const T &Elt) {
-    if (this->EndX < this->CapacityX) {
-    Retry:
-      ::new ((void*) this->end()) T(Elt);
-      this->setEnd(this->end()+1);
-      return;
-    }
-    this->grow();
-    goto Retry;
+    if (LLVM_UNLIKELY(this->EndX >= this->CapacityX))
+      this->grow();
+    ::new ((void*) this->end()) T(Elt);
+    this->setEnd(this->end()+1);
   }
 
-#if LLVM_USE_RVALUE_REFERENCES
   void push_back(T &&Elt) {
-    if (this->EndX < this->CapacityX) {
-    Retry:
-      ::new ((void*) this->end()) T(::std::move(Elt));
-      this->setEnd(this->end()+1);
-      return;
-    }
-    this->grow();
-    goto Retry;
+    if (LLVM_UNLIKELY(this->EndX >= this->CapacityX))
+      this->grow();
+    ::new ((void*) this->end()) T(::std::move(Elt));
+    this->setEnd(this->end()+1);
   }
-#endif
-  
+
   void pop_back() {
     this->setEnd(this->end()-1);
     this->end()->~T();
@@ -256,7 +243,8 @@ template <typename T, bool isPodLike>
 void SmallVectorTemplateBase<T, isPodLike>::grow(size_t MinSize) {
   size_t CurCapacity = this->capacity();
   size_t CurSize = this->size();
-  size_t NewCapacity = 2*CurCapacity + 1; // Always grow, even from zero.
+  // Always grow, even from zero.
+  size_t NewCapacity = size_t(NextPowerOf2(CurCapacity+2));
   if (NewCapacity < MinSize)
     NewCapacity = MinSize;
   T *NewElts = static_cast<T*>(malloc(NewCapacity*sizeof(T)));
@@ -287,22 +275,21 @@ protected:
   // No need to do a destroy loop for POD's.
   static void destroy_range(T *, T *) {}
 
-  /// move - Use move-assignment to move the range [I, E) onto the
+  /// Use move-assignment to move the range [I, E) onto the
   /// objects starting with "Dest".  For PODs, this is just memcpy.
   template<typename It1, typename It2>
   static It2 move(It1 I, It1 E, It2 Dest) {
     return ::std::copy(I, E, Dest);
   }
 
-  /// move_backward - Use move-assignment to move the range
-  /// [I, E) onto the objects ending at "Dest", moving objects
-  /// in reverse order.
+  /// Use move-assignment to move the range [I, E) onto the objects ending at
+  /// "Dest", moving objects in reverse order.
   template<typename It1, typename It2>
   static It2 move_backward(It1 I, It1 E, It2 Dest) {
     return ::std::copy_backward(I, E, Dest);
   }
 
-  /// uninitialized_move - Move the range [I, E) onto the uninitialized memory
+  /// Move the range [I, E) onto the uninitialized memory
   /// starting with "Dest", constructing elements into it as needed.
   template<typename It1, typename It2>
   static void uninitialized_move(It1 I, It1 E, It2 Dest) {
@@ -310,7 +297,7 @@ protected:
     uninitialized_copy(I, E, Dest);
   }
 
-  /// uninitialized_copy - Copy the range [I, E) onto the uninitialized memory
+  /// Copy the range [I, E) onto the uninitialized memory
   /// starting with "Dest", constructing elements into it as needed.
   template<typename It1, typename It2>
   static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
@@ -318,7 +305,7 @@ protected:
     std::uninitialized_copy(I, E, Dest);
   }
 
-  /// uninitialized_copy - Copy the range [I, E) onto the uninitialized memory
+  /// Copy the range [I, E) onto the uninitialized memory
   /// starting with "Dest", constructing elements into it as needed.
   template<typename T1, typename T2>
   static void uninitialized_copy(T1 *I, T1 *E, T2 *Dest) {
@@ -328,37 +315,32 @@ protected:
     memcpy(Dest, I, (E-I)*sizeof(T));
   }
 
-  /// grow - double the size of the allocated memory, guaranteeing space for at
+  /// Double the size of the allocated memory, guaranteeing space for at
   /// least one more element or MinSize if specified.
   void grow(size_t MinSize = 0) {
     this->grow_pod(MinSize*sizeof(T), sizeof(T));
   }
 public:
   void push_back(const T &Elt) {
-    if (this->EndX < this->CapacityX) {
-    Retry:
-      memcpy(this->end(), &Elt, sizeof(T));
-      this->setEnd(this->end()+1);
-      return;
-    }
-    this->grow();
-    goto Retry;
+    if (LLVM_UNLIKELY(this->EndX >= this->CapacityX))
+      this->grow();
+    memcpy(this->end(), &Elt, sizeof(T));
+    this->setEnd(this->end()+1);
   }
-  
+
   void pop_back() {
     this->setEnd(this->end()-1);
   }
 };
 
 
-/// SmallVectorImpl - This class consists of common code factored out of the
-/// SmallVector class to reduce code duplication based on the SmallVector 'N'
-/// template parameter.
+/// This class consists of common code factored out of the SmallVector class to
+/// reduce code duplication based on the SmallVector 'N' template parameter.
 template <typename T>
 class SmallVectorImpl : public SmallVectorTemplateBase<T, isPodLike<T>::value> {
   typedef SmallVectorTemplateBase<T, isPodLike<T>::value > SuperClass;
 
-  SmallVectorImpl(const SmallVectorImpl&); // DISABLED.
+  SmallVectorImpl(const SmallVectorImpl&) LLVM_DELETED_FUNCTION;
 public:
   typedef typename SuperClass::iterator iterator;
   typedef typename SuperClass::size_type size_type;
@@ -385,19 +367,20 @@ public:
     this->EndX = this->BeginX;
   }
 
-  void resize(unsigned N) {
+  void resize(size_type N) {
     if (N < this->size()) {
       this->destroy_range(this->begin()+N, this->end());
       this->setEnd(this->begin()+N);
     } else if (N > this->size()) {
       if (this->capacity() < N)
         this->grow(N);
-      std::uninitialized_fill(this->end(), this->begin()+N, T());
+      for (auto I = this->end(), E = this->begin() + N; I != E; ++I)
+        new (&*I) T();
       this->setEnd(this->begin()+N);
     }
   }
 
-  void resize(unsigned N, const T &NV) {
+  void resize(size_type N, const T &NV) {
     if (N < this->size()) {
       this->destroy_range(this->begin()+N, this->end());
       this->setEnd(this->begin()+N);
@@ -409,25 +392,20 @@ public:
     }
   }
 
-  void reserve(unsigned N) {
+  void reserve(size_type N) {
     if (this->capacity() < N)
       this->grow(N);
   }
 
-  T pop_back_val() {
-#if LLVM_USE_RVALUE_REFERENCES
+  T LLVM_ATTRIBUTE_UNUSED_RESULT pop_back_val() {
     T Result = ::std::move(this->back());
-#else
-    T Result = this->back();
-#endif
     this->pop_back();
     return Result;
   }
 
   void swap(SmallVectorImpl &RHS);
 
-  /// append - Add the specified range to the end of the SmallVector.
-  ///
+  /// Add the specified range to the end of the SmallVector.
   template<typename in_iter>
   void append(in_iter in_start, in_iter in_end) {
     size_type NumInputs = std::distance(in_start, in_end);
@@ -436,14 +414,11 @@ public:
       this->grow(this->size()+NumInputs);
 
     // Copy the new elements over.
-    // TODO: NEED To compile time dispatch on whether in_iter is a random access
-    // iterator to use the fast uninitialized_copy.
-    std::uninitialized_copy(in_start, in_end, this->end());
+    this->uninitialized_copy(in_start, in_end, this->end());
     this->setEnd(this->end() + NumInputs);
   }
 
-  /// append - Add the specified range to the end of the SmallVector.
-  ///
+  /// Add the specified range to the end of the SmallVector.
   void append(size_type NumInputs, const T &Elt) {
     // Grow allocated space if needed.
     if (NumInputs > size_type(this->capacity_ptr()-this->end()))
@@ -454,7 +429,7 @@ public:
     this->setEnd(this->end() + NumInputs);
   }
 
-  void assign(unsigned NumElts, const T &Elt) {
+  void assign(size_type NumElts, const T &Elt) {
     clear();
     if (this->capacity() < NumElts)
       this->grow(NumElts);
@@ -463,53 +438,60 @@ public:
   }
 
   iterator erase(iterator I) {
+    assert(I >= this->begin() && "Iterator to erase is out of bounds.");
+    assert(I < this->end() && "Erasing at past-the-end iterator.");
+
     iterator N = I;
     // Shift all elts down one.
-    std::copy(I+1, this->end(), I);
+    this->move(I+1, this->end(), I);
     // Drop the last elt.
     this->pop_back();
     return(N);
   }
 
   iterator erase(iterator S, iterator E) {
+    assert(S >= this->begin() && "Range to erase is out of bounds.");
+    assert(S <= E && "Trying to erase invalid range.");
+    assert(E <= this->end() && "Trying to erase past the end.");
+
     iterator N = S;
     // Shift all elts down.
-    iterator I = std::copy(E, this->end(), S);
+    iterator I = this->move(E, this->end(), S);
     // Drop the last elts.
     this->destroy_range(I, this->end());
     this->setEnd(I);
     return(N);
   }
 
-#if LLVM_USE_RVALUE_REFERENCES
   iterator insert(iterator I, T &&Elt) {
     if (I == this->end()) {  // Important special case for empty vector.
       this->push_back(::std::move(Elt));
       return this->end()-1;
     }
 
-    if (this->EndX < this->CapacityX) {
-    Retry:
-      ::new ((void*) this->end()) T(::std::move(this->back()));
-      this->setEnd(this->end()+1);
-      // Push everything else over.
-      this->move_backward(I, this->end()-1, this->end());
-
-      // If we just moved the element we're inserting, be sure to update
-      // the reference.
-      T *EltPtr = &Elt;
-      if (I <= EltPtr && EltPtr < this->EndX)
-        ++EltPtr;
+    assert(I >= this->begin() && "Insertion iterator is out of bounds.");
+    assert(I <= this->end() && "Inserting past the end of the vector.");
 
-      *I = ::std::move(*EltPtr);
-      return I;
+    if (this->EndX >= this->CapacityX) {
+      size_t EltNo = I-this->begin();
+      this->grow();
+      I = this->begin()+EltNo;
     }
-    size_t EltNo = I-this->begin();
-    this->grow();
-    I = this->begin()+EltNo;
-    goto Retry;
+
+    ::new ((void*) this->end()) T(::std::move(this->back()));
+    // Push everything else over.
+    this->move_backward(I, this->end()-1, this->end());
+    this->setEnd(this->end()+1);
+
+    // If we just moved the element we're inserting, be sure to update
+    // the reference.
+    T *EltPtr = &Elt;
+    if (I <= EltPtr && EltPtr < this->EndX)
+      ++EltPtr;
+
+    *I = ::std::move(*EltPtr);
+    return I;
   }
-#endif
 
   iterator insert(iterator I, const T &Elt) {
     if (I == this->end()) {  // Important special case for empty vector.
@@ -517,39 +499,43 @@ public:
       return this->end()-1;
     }
 
-    if (this->EndX < this->CapacityX) {
-    Retry:
-      ::new ((void*) this->end()) T(this->back());
-      this->setEnd(this->end()+1);
-      // Push everything else over.
-      this->move_backward(I, this->end()-1, this->end());
-
-      // If we just moved the element we're inserting, be sure to update
-      // the reference.
-      const T *EltPtr = &Elt;
-      if (I <= EltPtr && EltPtr < this->EndX)
-        ++EltPtr;
+    assert(I >= this->begin() && "Insertion iterator is out of bounds.");
+    assert(I <= this->end() && "Inserting past the end of the vector.");
 
-      *I = *EltPtr;
-      return I;
+    if (this->EndX >= this->CapacityX) {
+      size_t EltNo = I-this->begin();
+      this->grow();
+      I = this->begin()+EltNo;
     }
-    size_t EltNo = I-this->begin();
-    this->grow();
-    I = this->begin()+EltNo;
-    goto Retry;
+    ::new ((void*) this->end()) T(std::move(this->back()));
+    // Push everything else over.
+    this->move_backward(I, this->end()-1, this->end());
+    this->setEnd(this->end()+1);
+
+    // If we just moved the element we're inserting, be sure to update
+    // the reference.
+    const T *EltPtr = &Elt;
+    if (I <= EltPtr && EltPtr < this->EndX)
+      ++EltPtr;
+
+    *I = *EltPtr;
+    return I;
   }
 
   iterator insert(iterator I, size_type NumToInsert, const T &Elt) {
+    // Convert iterator to elt# to avoid invalidating iterator when we reserve()
+    size_t InsertElt = I - this->begin();
+
     if (I == this->end()) {  // Important special case for empty vector.
       append(NumToInsert, Elt);
-      return this->end()-1;
+      return this->begin()+InsertElt;
     }
 
-    // Convert iterator to elt# to avoid invalidating iterator when we reserve()
-    size_t InsertElt = I - this->begin();
+    assert(I >= this->begin() && "Insertion iterator is out of bounds.");
+    assert(I <= this->end() && "Inserting past the end of the vector.");
 
     // Ensure there is enough space.
-    reserve(static_cast<unsigned>(this->size() + NumToInsert));
+    reserve(this->size() + NumToInsert);
 
     // Uninvalidate the iterator.
     I = this->begin()+InsertElt;
@@ -560,7 +546,8 @@ public:
     // reallocate the vector.
     if (size_t(this->end()-I) >= NumToInsert) {
       T *OldEnd = this->end();
-      append(this->end()-NumToInsert, this->end());
+      append(std::move_iterator<iterator>(this->end() - NumToInsert),
+             std::move_iterator<iterator>(this->end()));
 
       // Copy the existing elements that get replaced.
       this->move_backward(I, OldEnd-NumToInsert, OldEnd);
@@ -572,11 +559,11 @@ public:
     // Otherwise, we're inserting more elements than exist already, and we're
     // not inserting at the end.
 
-    // Copy over the elements that we're about to overwrite.
+    // Move over the elements that we're about to overwrite.
     T *OldEnd = this->end();
     this->setEnd(this->end() + NumToInsert);
     size_t NumOverwritten = OldEnd-I;
-    this->uninitialized_copy(I, OldEnd, this->end()-NumOverwritten);
+    this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten);
 
     // Replace the overwritten part.
     std::fill_n(I, NumOverwritten, Elt);
@@ -588,17 +575,21 @@ public:
 
   template<typename ItTy>
   iterator insert(iterator I, ItTy From, ItTy To) {
+    // Convert iterator to elt# to avoid invalidating iterator when we reserve()
+    size_t InsertElt = I - this->begin();
+
     if (I == this->end()) {  // Important special case for empty vector.
       append(From, To);
-      return this->end()-1;
+      return this->begin()+InsertElt;
     }
 
+    assert(I >= this->begin() && "Insertion iterator is out of bounds.");
+    assert(I <= this->end() && "Inserting past the end of the vector.");
+
     size_t NumToInsert = std::distance(From, To);
-    // Convert iterator to elt# to avoid invalidating iterator when we reserve()
-    size_t InsertElt = I - this->begin();
 
     // Ensure there is enough space.
-    reserve(static_cast<unsigned>(this->size() + NumToInsert));
+    reserve(this->size() + NumToInsert);
 
     // Uninvalidate the iterator.
     I = this->begin()+InsertElt;
@@ -609,7 +600,8 @@ public:
     // reallocate the vector.
     if (size_t(this->end()-I) >= NumToInsert) {
       T *OldEnd = this->end();
-      append(this->end()-NumToInsert, this->end());
+      append(std::move_iterator<iterator>(this->end() - NumToInsert),
+             std::move_iterator<iterator>(this->end()));
 
       // Copy the existing elements that get replaced.
       this->move_backward(I, OldEnd-NumToInsert, OldEnd);
@@ -621,16 +613,16 @@ public:
     // Otherwise, we're inserting more elements than exist already, and we're
     // not inserting at the end.
 
-    // Copy over the elements that we're about to overwrite.
+    // Move over the elements that we're about to overwrite.
     T *OldEnd = this->end();
     this->setEnd(this->end() + NumToInsert);
     size_t NumOverwritten = OldEnd-I;
-    this->uninitialized_copy(I, OldEnd, this->end()-NumOverwritten);
+    this->uninitialized_move(I, OldEnd, this->end()-NumOverwritten);
 
     // Replace the overwritten part.
-    for (; NumOverwritten > 0; --NumOverwritten) {
-      *I = *From;
-      ++I; ++From;
+    for (T *J = I; NumOverwritten > 0; --NumOverwritten) {
+      *J = *From;
+      ++J; ++From;
     }
 
     // Insert the non-overwritten middle part.
@@ -638,11 +630,54 @@ public:
     return I;
   }
 
+#if LLVM_HAS_VARIADIC_TEMPLATES
+  template <typename... ArgTypes> void emplace_back(ArgTypes &&... Args) {
+    if (LLVM_UNLIKELY(this->EndX >= this->CapacityX))
+      this->grow();
+    ::new ((void *)this->end()) T(std::forward<ArgTypes>(Args)...);
+    this->setEnd(this->end() + 1);
+  }
+#else
+private:
+  template <typename Constructor> void emplace_back_impl(Constructor construct) {
+    if (LLVM_UNLIKELY(this->EndX >= this->CapacityX))
+      this->grow();
+    construct((void *)this->end());
+    this->setEnd(this->end() + 1);
+  }
+
+public:
+  void emplace_back() {
+    emplace_back_impl([](void *Mem) { ::new (Mem) T(); });
+  }
+  template <typename T1> void emplace_back(T1 &&A1) {
+    emplace_back_impl([&](void *Mem) { ::new (Mem) T(std::forward<T1>(A1)); });
+  }
+  template <typename T1, typename T2> void emplace_back(T1 &&A1, T2 &&A2) {
+    emplace_back_impl([&](void *Mem) {
+      ::new (Mem) T(std::forward<T1>(A1), std::forward<T2>(A2));
+    });
+  }
+  template <typename T1, typename T2, typename T3>
+  void emplace_back(T1 &&A1, T2 &&A2, T3 &&A3) {
+    T(std::forward<T1>(A1), std::forward<T2>(A2), std::forward<T3>(A3));
+    emplace_back_impl([&](void *Mem) {
+      ::new (Mem)
+          T(std::forward<T1>(A1), std::forward<T2>(A2), std::forward<T3>(A3));
+    });
+  }
+  template <typename T1, typename T2, typename T3, typename T4>
+  void emplace_back(T1 &&A1, T2 &&A2, T3 &&A3, T4 &&A4) {
+    emplace_back_impl([&](void *Mem) {
+      ::new (Mem) T(std::forward<T1>(A1), std::forward<T2>(A2),
+                    std::forward<T3>(A3), std::forward<T4>(A4));
+    });
+  }
+#endif // LLVM_HAS_VARIADIC_TEMPLATES
+
   SmallVectorImpl &operator=(const SmallVectorImpl &RHS);
 
-#if LLVM_USE_RVALUE_REFERENCES
   SmallVectorImpl &operator=(SmallVectorImpl &&RHS);
-#endif
 
   bool operator==(const SmallVectorImpl &RHS) const {
     if (this->size() != RHS.size()) return false;
@@ -657,8 +692,8 @@ public:
                                         RHS.begin(), RHS.end());
   }
 
-  /// set_size - Set the array size to \arg N, which the current array must have
-  /// enough capacity for.
+  /// Set the array size to \p N, which the current array must have enough
+  /// capacity for.
   ///
   /// This does not construct or destroy any elements in the vector.
   ///
@@ -666,7 +701,7 @@ public:
   /// of the buffer when they know that more elements are available, and only
   /// update the size later. This avoids the cost of value initializing elements
   /// which will only be overwritten.
-  void set_size(unsigned N) {
+  void set_size(size_type N) {
     assert(N <= this->capacity());
     this->setEnd(this->begin() + N);
   }
@@ -692,7 +727,7 @@ void SmallVectorImpl<T>::swap(SmallVectorImpl<T> &RHS) {
   // Swap the shared elements.
   size_t NumShared = this->size();
   if (NumShared > RHS.size()) NumShared = RHS.size();
-  for (unsigned i = 0; i != static_cast<unsigned>(NumShared); ++i)
+  for (size_type i = 0; i != NumShared; ++i)
     std::swap((*this)[i], RHS[i]);
 
   // Copy over the extra elts.
@@ -760,7 +795,6 @@ SmallVectorImpl<T> &SmallVectorImpl<T>::
   return *this;
 }
 
-#if LLVM_USE_RVALUE_REFERENCES
 template <typename T>
 SmallVectorImpl<T> &SmallVectorImpl<T>::operator=(SmallVectorImpl<T> &&RHS) {
   // Avoid self-assignment.
@@ -809,7 +843,7 @@ SmallVectorImpl<T> &SmallVectorImpl<T>::operator=(SmallVectorImpl<T> &&RHS) {
     this->grow(RHSSize);
   } else if (CurSize) {
     // Otherwise, use assignment for the already-constructed elements.
-    this->move(RHS.begin(), RHS.end(), this->begin());
+    this->move(RHS.begin(), RHS.begin()+CurSize, this->begin());
   }
 
   // Move-construct the new elements in place.
@@ -822,9 +856,19 @@ SmallVectorImpl<T> &SmallVectorImpl<T>::operator=(SmallVectorImpl<T> &&RHS) {
   RHS.clear();
   return *this;
 }
-#endif
 
-/// SmallVector - This is a 'vector' (really, a variable-sized array), optimized
+/// Storage for the SmallVector elements which aren't contained in
+/// SmallVectorTemplateCommon. There are 'N-1' elements here. The remaining '1'
+/// element is in the base class. This is specialized for the N=1 and N=0 cases
+/// to avoid allocating unnecessary storage.
+template <typename T, unsigned N>
+struct SmallVectorStorage {
+  typename SmallVectorTemplateCommon<T>::U InlineElts[N - 1];
+};
+template <typename T> struct SmallVectorStorage<T, 1> {};
+template <typename T> struct SmallVectorStorage<T, 0> {};
+
+/// This is a 'vector' (really, a variable-sized array), optimized
 /// for the case when the array is small.  It contains some number of elements
 /// in-place, which allows it to avoid heap allocation when the actual number of
 /// elements is below that threshold.  This allows normal "small" cases to be
@@ -834,41 +878,29 @@ SmallVectorImpl<T> &SmallVectorImpl<T>::operator=(SmallVectorImpl<T> &&RHS) {
 ///
 template <typename T, unsigned N>
 class SmallVector : public SmallVectorImpl<T> {
-  /// InlineElts - These are 'N-1' elements that are stored inline in the body
-  /// of the vector.  The extra '1' element is stored in SmallVectorImpl.
-  typedef typename SmallVectorImpl<T>::U U;
-  enum {
-    // MinUs - The number of U's require to cover N T's.
-    MinUs = (static_cast<unsigned int>(sizeof(T))*N +
-             static_cast<unsigned int>(sizeof(U)) - 1) /
-            static_cast<unsigned int>(sizeof(U)),
-
-    // NumInlineEltsElts - The number of elements actually in this array.  There
-    // is already one in the parent class, and we have to round up to avoid
-    // having a zero-element array.
-    NumInlineEltsElts = MinUs > 1 ? (MinUs - 1) : 1,
-
-    // NumTsAvailable - The number of T's we actually have space for, which may
-    // be more than N due to rounding.
-    NumTsAvailable = (NumInlineEltsElts+1)*static_cast<unsigned int>(sizeof(U))/
-                     static_cast<unsigned int>(sizeof(T))
-  };
-  U InlineElts[NumInlineEltsElts];
+  /// Inline space for elements which aren't stored in the base class.
+  SmallVectorStorage<T, N> Storage;
 public:
-  SmallVector() : SmallVectorImpl<T>(NumTsAvailable) {
+  SmallVector() : SmallVectorImpl<T>(N) {
   }
 
-  explicit SmallVector(unsigned Size, const T &Value = T())
-    : SmallVectorImpl<T>(NumTsAvailable) {
+  explicit SmallVector(size_t Size, const T &Value = T())
+    : SmallVectorImpl<T>(N) {
     this->assign(Size, Value);
   }
 
   template<typename ItTy>
-  SmallVector(ItTy S, ItTy E) : SmallVectorImpl<T>(NumTsAvailable) {
+  SmallVector(ItTy S, ItTy E) : SmallVectorImpl<T>(N) {
     this->append(S, E);
   }
 
-  SmallVector(const SmallVector &RHS) : SmallVectorImpl<T>(NumTsAvailable) {
+  template <typename RangeTy>
+  explicit SmallVector(const llvm::iterator_range<RangeTy> R)
+      : SmallVectorImpl<T>(N) {
+    this->append(R.begin(), R.end());
+  }
+
+  SmallVector(const SmallVector &RHS) : SmallVectorImpl<T>(N) {
     if (!RHS.empty())
       SmallVectorImpl<T>::operator=(RHS);
   }
@@ -878,8 +910,7 @@ public:
     return *this;
   }
 
-#if LLVM_USE_RVALUE_REFERENCES
-  SmallVector(SmallVector &&RHS) : SmallVectorImpl<T>(NumTsAvailable) {
+  SmallVector(SmallVector &&RHS) : SmallVectorImpl<T>(N) {
     if (!RHS.empty())
       SmallVectorImpl<T>::operator=(::std::move(RHS));
   }
@@ -888,34 +919,15 @@ public:
     SmallVectorImpl<T>::operator=(::std::move(RHS));
     return *this;
   }
-#endif
-
-};
-
-/// Specialize SmallVector at N=0.  This specialization guarantees
-/// that it can be instantiated at an incomplete T if none of its
-/// members are required.
-template <typename T>
-class SmallVector<T,0> : public SmallVectorImpl<T> {
-public:
-  SmallVector() : SmallVectorImpl<T>(0) {}
-
-  explicit SmallVector(unsigned Size, const T &Value = T())
-    : SmallVectorImpl<T>(0) {
-    this->assign(Size, Value);
-  }
 
-  template<typename ItTy>
-  SmallVector(ItTy S, ItTy E) : SmallVectorImpl<T>(0) {
-    this->append(S, E);
-  }
-
-  SmallVector(const SmallVector &RHS) : SmallVectorImpl<T>(0) {
-    SmallVectorImpl<T>::operator=(RHS);
+  SmallVector(SmallVectorImpl<T> &&RHS) : SmallVectorImpl<T>(N) {
+    if (!RHS.empty())
+      SmallVectorImpl<T>::operator=(::std::move(RHS));
   }
 
-  SmallVector &operator=(const SmallVectorImpl<T> &RHS) {
-    return SmallVectorImpl<T>::operator=(RHS);
+  const SmallVector &operator=(SmallVectorImpl<T> &&RHS) {
+    SmallVectorImpl<T>::operator=(::std::move(RHS));
+    return *this;
   }
 
 };