diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp
index 0d016e21f26..ecc83dfceb6 100644
--- a/lib/Analysis/ValueTracking.cpp
+++ b/lib/Analysis/ValueTracking.cpp
@@ -1370,6 +1370,8 @@ Value *llvm::isBytewiseValue(Value *V) {
     
     return Val;
   }
+
+  // FIXME: Vector types (e.g., <4 x i32> <i32 -1, i32 -1, i32 -1, i32 -1>).
   
   // Conceptually, we could handle things like:
   //   %a = zext i8 %X to i16
diff --git a/test/Transforms/MemCpyOpt/form-memset.ll b/test/Transforms/MemCpyOpt/form-memset.ll
index e5ace332702..8832f897b08 100644
--- a/test/Transforms/MemCpyOpt/form-memset.ll
+++ b/test/Transforms/MemCpyOpt/form-memset.ll
@@ -236,3 +236,15 @@ define void @test7(i32* nocapture %c) nounwind optsize {
 ; CHECK: call void @llvm.memset.p0i8.i64(i8* %5, i8 -1, i64 20, i32 4, i1 false)
   ret void
 }
+
+%struct.test8 = type { [4 x i32] }
+
+define void @test8() {
+entry:
+  %memtmp = alloca %struct.test8, align 16
+  %0 = bitcast %struct.test8* %memtmp to <4 x i32>*
+  store <4 x i32> <i32 -1, i32 -1, i32 -1, i32 -1>, <4 x i32>* %0, align 16
+  ret void
+; CHECK: @test8
+; CHECK: store <4 x i32> <i32 -1, i32 -1, i32 -1, i32 -1>, <4 x i32>* %0, align 16
+}