Bring the return value of SmallVector::insert in line with std::vector::insert.

It always returns the iterator for the first inserted element, or the passed in
iterator if the inserted range was empty. Flesh out the unit test more and fix
all the cases it uncovered so far.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158645 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 41 insertions, 14 deletions

diff --git a/include/llvm/ADT/SmallVector.h b/include/llvm/ADT/SmallVector.h
index 02eee62..2d71249 100644
--- a/include/llvm/ADT/SmallVector.h
+++ b/include/llvm/ADT/SmallVector.h
@@ -540,14 +540,14 @@ public:
   }
 
   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 NumToInsert == 0 ? this->end() : this->end()-1;
+      return this->begin()+InsertElt;
     }
 
-    // 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));
 
@@ -588,14 +588,15 @@ 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 From == To ? this->end() : this->end()-1;
+      return this->begin()+InsertElt;
     }
 
     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));
@@ -628,9 +629,9 @@ public:
     this->uninitialized_copy(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.
diff --git a/unittests/ADT/SmallVectorTest.cpp b/unittests/ADT/SmallVectorTest.cpp
index 8f6d2f4..d35e5bc 100644
--- a/unittests/ADT/SmallVectorTest.cpp
+++ b/unittests/ADT/SmallVectorTest.cpp
@@ -342,7 +342,9 @@ TEST_F(SmallVectorTest, InsertTest) {
   SCOPED_TRACE("InsertTest");
 
   makeSequence(theVector, 1, 3);
-  theVector.insert(theVector.begin() + 1, Constructable(77));
+  VectorType::iterator I =
+    theVector.insert(theVector.begin() + 1, Constructable(77));
+  EXPECT_EQ(theVector.begin() + 1, I);
   assertValuesInOrder(theVector, 4u, 1, 77, 2, 3);
 }
 
@@ -351,24 +353,48 @@ TEST_F(SmallVectorTest, InsertRepeatedTest) {
   SCOPED_TRACE("InsertRepeatedTest");
 
   makeSequence(theVector, 10, 15);
-  theVector.insert(theVector.begin() + 1, 2, Constructable(16));
+  VectorType::iterator I =
+    theVector.insert(theVector.begin() + 1, 2, Constructable(16));
+  EXPECT_EQ(theVector.begin() + 1, I);
   assertValuesInOrder(theVector, 8u, 10, 16, 16, 11, 12, 13, 14, 15);
 
+  // Insert at end.
+  I = theVector.insert(theVector.end(), 2, Constructable(16));
+  EXPECT_EQ(theVector.begin() + 8, I);
+  assertValuesInOrder(theVector, 10u, 10, 16, 16, 11, 12, 13, 14, 15, 16, 16);
+
+  // Empty insert.
   EXPECT_EQ(theVector.end(),
             theVector.insert(theVector.end(), 0, Constructable(42)));
+  EXPECT_EQ(theVector.begin() + 1,
+            theVector.insert(theVector.begin() + 1, 0, Constructable(42)));
 }
 
 // Insert range.
 TEST_F(SmallVectorTest, InsertRangeTest) {
-  SCOPED_TRACE("InsertRepeatedTest");
+  SCOPED_TRACE("InsertRangeTest");
+
+  Constructable Arr[3] =
+    { Constructable(77), Constructable(77), Constructable(77) };
 
   makeSequence(theVector, 1, 3);
-  theVector.insert(theVector.begin() + 1, 3, Constructable(77));
+  VectorType::iterator I =
+    theVector.insert(theVector.begin() + 1, Arr, Arr+3);
+  EXPECT_EQ(theVector.begin() + 1, I);
   assertValuesInOrder(theVector, 6u, 1, 77, 77, 77, 2, 3);
 
+  // Insert at end.
+  I = theVector.insert(theVector.end(), Arr, Arr+3);
+  EXPECT_EQ(theVector.begin() + 6, I);
+  assertValuesInOrder(theVector, 9u, 1, 77, 77, 77, 2, 3, 77, 77, 77);
+
+  // Empty insert.
   EXPECT_EQ(theVector.end(), theVector.insert(theVector.end(),
                                               theVector.begin(),
                                               theVector.begin()));
+  EXPECT_EQ(theVector.begin() + 1, theVector.insert(theVector.begin() + 1,
+                                                    theVector.begin(),
+                                                    theVector.begin()));
 }
 
 // Comparison tests.