diff --git a/include/llvm/IntrinsicInst.h b/include/llvm/IntrinsicInst.h
index 6a8f3763926..1e1dca2ebab 100644
--- a/include/llvm/IntrinsicInst.h
+++ b/include/llvm/IntrinsicInst.h
@@ -320,6 +320,28 @@ namespace llvm {
     }
   };
   
+  /// MemoryUseIntrinsic - This is the common base class for the memory use
+  /// marker intrinsics.
+  ///
+  struct MemoryUseIntrinsic : public IntrinsicInst {
+
+    // Methods for support type inquiry through isa, cast, and dyn_cast:
+    static inline bool classof(const MemoryUseIntrinsic *) { return true; }
+    static inline bool classof(const IntrinsicInst *I) {
+      switch (I->getIntrinsicID()) {
+      case Intrinsic::lifetime_start:
+      case Intrinsic::lifetime_end:
+      case Intrinsic::invariant_start:
+      case Intrinsic::invariant_end:
+        return true;
+      default: return false;
+      }
+    }
+    static inline bool classof(const Value *V) {
+      return isa<IntrinsicInst>(V) && classof(cast<IntrinsicInst>(V));
+    }
+  };
+
 }
 
 #endif
diff --git a/lib/Transforms/Utils/Local.cpp b/lib/Transforms/Utils/Local.cpp
index 0167ea0bcb2..aef0f5f03c2 100644
--- a/lib/Transforms/Utils/Local.cpp
+++ b/lib/Transforms/Utils/Local.cpp
@@ -252,6 +252,9 @@ bool llvm::isInstructionTriviallyDead(Instruction *I) {
   // We don't want debug info removed by anything this general.
   if (isa<DbgInfoIntrinsic>(I)) return false;
 
+  // Likewise for memory use markers.
+  if (isa<MemoryUseIntrinsic>(I)) return false;
+
   if (!I->mayHaveSideEffects()) return true;
 
   // Special case intrinsics that "may have side effects" but can be deleted
diff --git a/test/Transforms/InstCombine/invariant.ll b/test/Transforms/InstCombine/invariant.ll
new file mode 100644
index 00000000000..c67ad331959
--- /dev/null
+++ b/test/Transforms/InstCombine/invariant.ll
@@ -0,0 +1,16 @@
+; Test to make sure unused llvm.invariant.start calls are not trivially eliminated
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+declare void @g(i8*)
+
+declare { }* @llvm.invariant.start(i64, i8* nocapture) nounwind readonly
+
+define i8 @f() {
+  %a = alloca i8                                  ; <i8*> [#uses=4]
+  store i8 0, i8* %a
+  %i = call { }* @llvm.invariant.start(i64 1, i8* %a) ; <{ }*> [#uses=0]
+  ; CHECK: call { }* @llvm.invariant.start
+  call void @g(i8* %a)
+  %r = load i8* %a                                ; <i8> [#uses=1]
+  ret i8 %r
+}