Index: include/llvm/ADT/IntervalMap.h
===================================================================
--- include/llvm/ADT/IntervalMap.h
+++ include/llvm/ADT/IntervalMap.h
@@ -1134,6 +1134,18 @@
     I.find(x);
     return I;
   }
+
+  /// contains(a, b) - Return true if this map contains at least one value from
+  /// the range [a;b]
+  bool contains(KeyT a, KeyT b) {
+    assert(Traits::nonEmpty(a, b));
+    const_iterator I = find(a);
+    if (!I.valid())
+      return false;
+    // [a;b] and [x;y] intersect iff x<=b and a<=y. The find() call guarantees
+    // the second part, so it is sufficient to check the first one.
+    return !Traits::stopLess(b, I.start());
+  }
 };
 
 /// treeSafeLookup - Return the mapped value at x or NotFound, assuming a
Index: unittests/ADT/IntervalMapTest.cpp
===================================================================
--- unittests/ADT/IntervalMapTest.cpp
+++ unittests/ADT/IntervalMapTest.cpp
@@ -611,6 +611,50 @@
 
 }
 
+TEST(IntervalMapTest, Contains) {
+  UUMap::Allocator allocator;
+  UUMap map(allocator);
+  map.insert(10, 20, 0);
+  map.insert(30, 40, 0);
+  map.insert(50, 60, 0);
+
+  EXPECT_FALSE(map.contains(0, 9));
+  EXPECT_TRUE(map.contains(0, 10));
+  EXPECT_TRUE(map.contains(0, 15));
+  EXPECT_TRUE(map.contains(0, 25));
+  EXPECT_TRUE(map.contains(0, 45));
+  EXPECT_TRUE(map.contains(10, 45));
+  EXPECT_TRUE(map.contains(30, 45));
+  EXPECT_TRUE(map.contains(35, 36));
+  EXPECT_TRUE(map.contains(40, 45));
+  EXPECT_FALSE(map.contains(45, 45));
+  EXPECT_TRUE(map.contains(60, 60));
+  EXPECT_TRUE(map.contains(60, 66));
+  EXPECT_FALSE(map.contains(66, 66));
+}
+
+TEST(IntervalMapTest, ContainsHalfOpen) {
+  UUHalfOpenMap::Allocator allocator;
+  UUHalfOpenMap map(allocator);
+  map.insert(10, 20, 0);
+  map.insert(30, 40, 0);
+  map.insert(50, 60, 0);
+
+  EXPECT_FALSE(map.contains(0, 9));
+  EXPECT_FALSE(map.contains(0, 10));
+  EXPECT_TRUE(map.contains(0, 15));
+  EXPECT_TRUE(map.contains(0, 25));
+  EXPECT_TRUE(map.contains(0, 45));
+  EXPECT_TRUE(map.contains(10, 45));
+  EXPECT_TRUE(map.contains(30, 45));
+  EXPECT_TRUE(map.contains(35, 36));
+  EXPECT_FALSE(map.contains(40, 45));
+  EXPECT_FALSE(map.contains(45, 46));
+  EXPECT_FALSE(map.contains(60, 61));
+  EXPECT_FALSE(map.contains(60, 66));
+  EXPECT_FALSE(map.contains(66, 67));
+}
+
 TEST(IntervalMapOverlapsTest, SmallMaps) {
   typedef IntervalMapOverlaps<UUMap,UUMap> UUOverlaps;
   UUMap::Allocator allocator;