Index: compiler-rt/trunk/lib/sanitizer_common/sanitizer_vector.h
===================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_vector.h
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_vector.h
@@ -82,6 +82,10 @@
       return;
     }
     uptr old_size = Size();
+    if (size <= old_size) {
+      end_ = begin_ + size;
+      return;
+    }
     EnsureSize(size);
     if (old_size < size) {
       for (uptr i = old_size; i < size; i++)
Index: compiler-rt/trunk/lib/sanitizer_common/tests/sanitizer_vector_test.cc
===================================================================
--- compiler-rt/trunk/lib/sanitizer_common/tests/sanitizer_vector_test.cc
+++ compiler-rt/trunk/lib/sanitizer_common/tests/sanitizer_vector_test.cc
@@ -39,4 +39,13 @@
   }
 }
 
+TEST(Vector, ResizeReduction) {
+  Vector<int> v;
+  v.PushBack(0);
+  v.PushBack(0);
+  EXPECT_EQ(v.Size(), 2u);
+  v.Resize(1);
+  EXPECT_EQ(v.Size(), 1u);
+}
+
 }  // namespace __sanitizer