diff --git a/lib/Analysis/InstructionSimplify.cpp b/lib/Analysis/InstructionSimplify.cpp
index aaf9de28da4..bb70d1cfc3c 100644
--- a/lib/Analysis/InstructionSimplify.cpp
+++ b/lib/Analysis/InstructionSimplify.cpp
@@ -710,7 +710,7 @@ static Constant *stripAndComputeConstantOffsets(const TargetData &TD,
   Visited.insert(V);
   do {
     if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
-      if (!accumulateGEPOffset(TD, GEP, Offset))
+      if (!GEP->isInBounds() || !accumulateGEPOffset(TD, GEP, Offset))
         break;
       V = GEP->getPointerOperand();
     } else if (Operator::getOpcode(V) == Instruction::BitCast) {
diff --git a/test/Transforms/InstSimplify/ptr_diff.ll b/test/Transforms/InstSimplify/ptr_diff.ll
index 013964ccfec..1eb1fd4c097 100644
--- a/test/Transforms/InstSimplify/ptr_diff.ll
+++ b/test/Transforms/InstSimplify/ptr_diff.ll
@@ -6,8 +6,8 @@ define i64 @ptrdiff1(i8* %ptr) {
 ; CHECK: @ptrdiff1
 ; CHECK-NEXT: ret i64 42
 
-  %first = getelementptr i8* %ptr, i32 0
-  %last = getelementptr i8* %ptr, i32 42
+  %first = getelementptr inbounds i8* %ptr, i32 0
+  %last = getelementptr inbounds i8* %ptr, i32 42
   %first.int = ptrtoint i8* %first to i64
   %last.int = ptrtoint i8* %last to i64
   %diff = sub i64 %last.int, %first.int
@@ -18,16 +18,31 @@ define i64 @ptrdiff2(i8* %ptr) {
 ; CHECK: @ptrdiff2
 ; CHECK-NEXT: ret i64 42
 
-  %first1 = getelementptr i8* %ptr, i32 0
-  %first2 = getelementptr i8* %first1, i32 1
-  %first3 = getelementptr i8* %first2, i32 2
-  %first4 = getelementptr i8* %first3, i32 4
-  %last1 = getelementptr i8* %first2, i32 48
-  %last2 = getelementptr i8* %last1, i32 8
-  %last3 = getelementptr i8* %last2, i32 -4
-  %last4 = getelementptr i8* %last3, i32 -4
+  %first1 = getelementptr inbounds i8* %ptr, i32 0
+  %first2 = getelementptr inbounds i8* %first1, i32 1
+  %first3 = getelementptr inbounds i8* %first2, i32 2
+  %first4 = getelementptr inbounds i8* %first3, i32 4
+  %last1 = getelementptr inbounds i8* %first2, i32 48
+  %last2 = getelementptr inbounds i8* %last1, i32 8
+  %last3 = getelementptr inbounds i8* %last2, i32 -4
+  %last4 = getelementptr inbounds i8* %last3, i32 -4
   %first.int = ptrtoint i8* %first4 to i64
   %last.int = ptrtoint i8* %last4 to i64
   %diff = sub i64 %last.int, %first.int
   ret i64 %diff
 }
+
+define i64 @ptrdiff3(i8* %ptr) {
+; Don't bother with non-inbounds GEPs.
+; CHECK: @ptrdiff3
+; CHECK: getelementptr
+; CHECK: sub
+; CHECK: ret
+
+  %first = getelementptr i8* %ptr, i32 0
+  %last = getelementptr i8* %ptr, i32 42
+  %first.int = ptrtoint i8* %first to i64
+  %last.int = ptrtoint i8* %last to i64
+  %diff = sub i64 %last.int, %first.int
+  ret i64 %diff
+}