ADT: Fix MapVector::erase()

Actually update the changed indexes in the map portion of `MapVector`
when erasing from the middle.  Add a unit test that checks for this.

Note that `MapVector::erase()` is a linear time operation (it was and
still is).  I'll commit a new method in a moment called
`MapVector::remove_if()` that deletes multiple entries in linear time,
which should be slightly less painful.

llvm-svn: 213084

1 files changed, 15 insertions, 0 deletions

diff --git a/llvm/unittests/ADT/MapVectorTest.cpp b/llvm/unittests/ADT/MapVectorTest.cpp
index 11178bc15e8..dd84e7ebd13 100644
--- a/llvm/unittests/ADT/MapVectorTest.cpp
+++ b/llvm/unittests/ADT/MapVectorTest.cpp
@@ -53,3 +53,18 @@ TEST(MapVectorTest, insert_pop) {
   EXPECT_EQ(MV[1], 2);
   EXPECT_EQ(MV[4], 7);
 }
+
+TEST(MapVectorTest, erase) {
+  MapVector<int, int> MV;
+
+  MV.insert(std::make_pair(1, 2));
+  MV.insert(std::make_pair(3, 4));
+  MV.insert(std::make_pair(5, 6));
+  ASSERT_EQ(MV.size(), 3u);
+
+  MV.erase(MV.find(1));
+  ASSERT_EQ(MV.size(), 2u);
+  ASSERT_EQ(MV.find(1), MV.end());
+  ASSERT_EQ(MV[3], 4);
+  ASSERT_EQ(MV[5], 6);
+}