Update SetVector to rely on the underlying set's insert to return a pair<iterator, bool>

This is to be consistent with StringSet and ultimately with the standard
library's associative container insert function.

This lead to updating SmallSet::insert to return pair<iterator, bool>,
and then to update SmallPtrSet::insert to return pair<iterator, bool>,
and then to update all the existing users of those functions...

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222334 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/ADT/PostOrderIterator.h

@@ -57,7 +57,7 @@ public:
   // Return true if edge destination should be visited.
   template<typename NodeType>
   bool insertEdge(NodeType *From, NodeType *To) {
-    return Visited.insert(To);
+    return Visited.insert(To).second;
   }
 
   // Called after all children of BB have been visited.

include/llvm/ADT/SetVector.h

@@ -100,7 +100,7 @@ public:
   /// \brief Insert a new element into the SetVector.
   /// \returns true iff the element was inserted into the SetVector.
   bool insert(const value_type &X) {
-    bool result = set_.insert(X);
+    bool result = set_.insert(X).second;
     if (result)
       vector_.push_back(X);
     return result;
@@ -110,7 +110,7 @@ public:
   template<typename It>
   void insert(It Start, It End) {
     for (; Start != End; ++Start)
-      if (set_.insert(*Start))
+      if (set_.insert(*Start).second)
         vector_.push_back(*Start);
   }
 

include/llvm/ADT/SmallPtrSet.h

@@ -100,7 +100,7 @@ protected:
   /// insert_imp - This returns true if the pointer was new to the set, false if
   /// it was already in the set.  This is hidden from the client so that the
   /// derived class can check that the right type of pointer is passed in.
-  bool insert_imp(const void * Ptr);
+  std::pair<const void *const *, bool> insert_imp(const void *Ptr);
 
   /// erase_imp - If the set contains the specified pointer, remove it and
   /// return true, otherwise return false.  This is hidden from the client so
@@ -253,10 +253,14 @@ protected:
       : SmallPtrSetImplBase(SmallStorage, SmallSize) {}
 
 public:
+  typedef SmallPtrSetIterator<PtrType> iterator;
+  typedef SmallPtrSetIterator<PtrType> const_iterator;
+
   /// insert - This returns true if the pointer was new to the set, false if it
   /// was already in the set.
-  bool insert(PtrType Ptr) {
-    return insert_imp(PtrTraits::getAsVoidPointer(Ptr));
+  std::pair<iterator, bool> insert(PtrType Ptr) {
+    auto p = insert_imp(PtrTraits::getAsVoidPointer(Ptr));
+    return std::make_pair(iterator(p.first, CurArray + CurArraySize), p.second);
   }
 
   /// erase - If the set contains the specified pointer, remove it and return
@@ -276,8 +280,6 @@ public:
       insert(*I);
   }
 
-  typedef SmallPtrSetIterator<PtrType> iterator;
-  typedef SmallPtrSetIterator<PtrType> const_iterator;
   inline iterator begin() const {
     return iterator(CurArray, CurArray+CurArraySize);
   }

include/llvm/ADT/SmallSet.h

@@ -14,6 +14,7 @@
 #ifndef LLVM_ADT_SMALLSET_H
 #define LLVM_ADT_SMALLSET_H
 
+#include "llvm/ADT/None.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include <set>
@@ -60,16 +61,21 @@ public:
 
   /// insert - Insert an element into the set if it isn't already there.
   /// Returns true if the element is inserted (it was not in the set before).
-  bool insert(const T &V) {
+  /// The first value of the returned pair is unused and provided for
+  /// partial compatibility with the standard library self-associative container
+  /// concept.
+  // FIXME: Add iterators that abstract over the small and large form, and then
+  // return those here.
+  std::pair<NoneType, bool> insert(const T &V) {
     if (!isSmall())
-      return Set.insert(V).second;
+      return std::make_pair(None, Set.insert(V).second);
 
     VIterator I = vfind(V);
     if (I != Vector.end())    // Don't reinsert if it already exists.
-      return false;
+      return std::make_pair(None, false);
     if (Vector.size() < N) {
       Vector.push_back(V);
-      return true;
+      return std::make_pair(None, true);
     }
 
     // Otherwise, grow from vector to set.
@@ -78,7 +84,7 @@ public:
       Vector.pop_back();
     }
     Set.insert(V);
-    return true;
+    return std::make_pair(None, true);
   }
 
   template <typename IterT>

include/llvm/Analysis/DominanceFrontierImpl.h

@@ -172,7 +172,7 @@ ForwardDominanceFrontierBase<BlockT>::calculate(const DomTreeT &DT,
     DomSetType &S = this->Frontiers[currentBB];
 
     // Visit each block only once.
-    if (visited.insert(currentBB)) {
+    if (visited.insert(currentBB).second) {
       // Loop over CFG successors to calculate DFlocal[currentNode]
       for (auto SI = BlockTraits::child_begin(currentBB),
                 SE = BlockTraits::child_end(currentBB);

include/llvm/Analysis/ScalarEvolutionExpressions.h

@@ -577,7 +577,7 @@ namespace llvm {
     SmallPtrSet<const SCEV *, 8> Visited;
 
     void push(const SCEV *S) {
-      if (Visited.insert(S) && Visitor.follow(S))
+      if (Visited.insert(S).second && Visitor.follow(S))
         Worklist.push_back(S);
     }
   public:

include/llvm/CodeGen/MachineDominators.h

@@ -303,7 +303,7 @@ public:
   void recordSplitCriticalEdge(MachineBasicBlock *FromBB,
                               MachineBasicBlock *ToBB,
                               MachineBasicBlock *NewBB) {
-    bool Inserted = NewBBs.insert(NewBB);
+    bool Inserted = NewBBs.insert(NewBB).second;
     (void)Inserted;
     assert(Inserted &&
            "A basic block inserted via edge splitting cannot appear twice");

include/llvm/Support/GenericDomTreeConstruction.h

@@ -125,7 +125,7 @@ Eval(DominatorTreeBase<typename GraphT::NodeType>& DT,
     typename GraphT::NodeType* VAncestor = DT.Vertex[VInfo.Parent];
 
     // Process Ancestor first
-    if (Visited.insert(VAncestor) && VInfo.Parent >= LastLinked) {
+    if (Visited.insert(VAncestor).second && VInfo.Parent >= LastLinked) {
       Work.push_back(VAncestor);
       continue;
     }