diff --git a/lib/Transforms/Vectorize/LoopVectorize.cpp b/lib/Transforms/Vectorize/LoopVectorize.cpp
index 9e7335af5f7..1d82c7b8f54 100644
--- a/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -2866,6 +2866,12 @@ bool LoopVectorizationLegality::canVectorizeInstrs() {
 
           DEBUG(dbgs() << "LV: Found an induction variable.\n");
           Inductions[Phi] = InductionInfo(StartValue, IK);
+
+          // Until we explicitly handle the case of an induction variable with
+          // an outside loop user we have to give up vectorizing this loop.
+          if (hasOutsideLoopUser(TheLoop, it, AllowedExit))
+            return false;
+
           continue;
         }
 
diff --git a/test/Transforms/LoopVectorize/no_outside_user.ll b/test/Transforms/LoopVectorize/no_outside_user.ll
index 6f0357c5e54..c83d7aac7b6 100644
--- a/test/Transforms/LoopVectorize/no_outside_user.ll
+++ b/test/Transforms/LoopVectorize/no_outside_user.ll
@@ -12,6 +12,7 @@ target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f3
 ; We used to vectorize this loop. But it has a value that is used outside of the
 ; and is not a recognized reduction variable "tmp17".
 
+; CHECK-LABEL: main
 ; CHECK-NOT: <2 x i32>
 
 define i32 @main()  {
@@ -38,4 +39,33 @@ f1.exit.loopexit:
   ret i32 %.lcssa
 }
 
+; Don't vectorize this loop. Its phi node (induction variable) has an outside
+; loop user. We currently don't handle this case.
+; PR17179
 
+; CHECK-LABEL: test2
+; CHECK-NOT:  <2 x
+
+@x1 = common global i32 0, align 4
+@x2 = common global i32 0, align 4
+@x0 = common global i32 0, align 4
+
+define i32 @test2()  {
+entry:
+  store i32 0, i32* @x1, align 4
+  %0 = load i32* @x0, align 4
+  br label %for.cond1.preheader
+
+for.cond1.preheader:
+  %inc7 = phi i32 [ 0, %entry ], [ %inc, %for.cond1.preheader ]
+  %inc = add nsw i32 %inc7, 1
+  %cmp = icmp eq i32 %inc, 52
+  br i1 %cmp, label %for.end5, label %for.cond1.preheader
+
+for.end5:
+  %inc7.lcssa = phi i32 [ %inc7, %for.cond1.preheader ]
+  %xor = xor i32 %inc7.lcssa, %0
+  store i32 52, i32* @x1, align 4
+  store i32 1, i32* @x2, align 4
+  ret i32 %xor
+}