diff --git a/lib/IR/Instructions.cpp b/lib/IR/Instructions.cpp
index 5a50b736500..c805b72d92d 100644
--- a/lib/IR/Instructions.cpp
+++ b/lib/IR/Instructions.cpp
@@ -2818,30 +2818,55 @@ CastInst::castIsValid(Instruction::CastOps op, Value *S, Type *DstTy) {
         return false;
     return SrcTy->getScalarType()->isIntegerTy() &&
            DstTy->getScalarType()->isPointerTy();
-  case Instruction::BitCast:
+  case Instruction::BitCast: {
+    PointerType *SrcPtrTy = dyn_cast<PointerType>(SrcTy->getScalarType());
+    PointerType *DstPtrTy = dyn_cast<PointerType>(DstTy->getScalarType());
+
     // BitCast implies a no-op cast of type only. No bits change.
     // However, you can't cast pointers to anything but pointers.
-    if (SrcTy->isPtrOrPtrVectorTy() != DstTy->isPtrOrPtrVectorTy())
+    if (!SrcPtrTy != !DstPtrTy)
       return false;
 
     // For non-pointer cases, the cast is okay if the source and destination bit
     // widths are identical.
-    if (!SrcTy->isPtrOrPtrVectorTy())
+    if (!SrcPtrTy)
       return SrcTy->getPrimitiveSizeInBits() == DstTy->getPrimitiveSizeInBits();
 
-    // If both are pointers then the address spaces must match and vector of
-    // pointers must have the same number of elements.
-    return SrcTy->getPointerAddressSpace() == DstTy->getPointerAddressSpace() &&
-           SrcTy->isVectorTy() == DstTy->isVectorTy() &&
-           (!SrcTy->isVectorTy() ||
-            SrcTy->getVectorNumElements() == SrcTy->getVectorNumElements());
+    // If both are pointers then the address spaces must match.
+    if (SrcPtrTy->getAddressSpace() != DstPtrTy->getAddressSpace())
+      return false;
 
-  case Instruction::AddrSpaceCast:
-    return SrcTy->isPtrOrPtrVectorTy() && DstTy->isPtrOrPtrVectorTy() &&
-           SrcTy->getPointerAddressSpace() != DstTy->getPointerAddressSpace() &&
-           SrcTy->isVectorTy() == DstTy->isVectorTy() &&
-           (!SrcTy->isVectorTy() ||
-            SrcTy->getVectorNumElements() == SrcTy->getVectorNumElements());
+    // A vector of pointers must have the same number of elements.
+    if (VectorType *SrcVecTy = dyn_cast<VectorType>(SrcTy)) {
+      if (VectorType *DstVecTy = dyn_cast<VectorType>(DstTy))
+        return (SrcVecTy->getNumElements() == DstVecTy->getNumElements());
+
+      return false;
+    }
+
+    return true;
+  }
+  case Instruction::AddrSpaceCast: {
+    PointerType *SrcPtrTy = dyn_cast<PointerType>(SrcTy->getScalarType());
+    if (!SrcPtrTy)
+      return false;
+
+    PointerType *DstPtrTy = dyn_cast<PointerType>(DstTy->getScalarType());
+    if (!DstPtrTy)
+      return false;
+
+    if (SrcPtrTy->getAddressSpace() == DstPtrTy->getAddressSpace())
+      return false;
+
+    if (VectorType *SrcVecTy = dyn_cast<VectorType>(SrcTy)) {
+      if (VectorType *DstVecTy = dyn_cast<VectorType>(DstTy))
+        return (SrcVecTy->getNumElements() == DstVecTy->getNumElements());
+
+      return false;
+    }
+
+    return true;
+  }
   }
 }
 
diff --git a/test/Assembler/invalid_cast3.ll b/test/Assembler/invalid_cast3.ll
new file mode 100644
index 00000000000..cc956cee59a
--- /dev/null
+++ b/test/Assembler/invalid_cast3.ll
@@ -0,0 +1,7 @@
+; RUN: not llvm-as < %s 2>&1 | FileCheck %s
+
+; CHECK: invalid cast opcode for cast from '<4 x i32*>' to '<2 x i32*>'
+define <2 x i32*> @illegal_vector_pointer_bitcast_num_elements(<4 x i32*> %c) {
+  %bc = bitcast <4 x i32*> %c to <2 x i32*>
+  ret <2 x i32*> %bc
+}
diff --git a/unittests/IR/InstructionsTest.cpp b/unittests/IR/InstructionsTest.cpp
index 0ae236cb3cc..cbdf18c6468 100644
--- a/unittests/IR/InstructionsTest.cpp
+++ b/unittests/IR/InstructionsTest.cpp
@@ -145,6 +145,7 @@ TEST(InstructionsTest, CastInst) {
 
   Type *V2Int64PtrTy = VectorType::get(Int64PtrTy, 2);
   Type *V2Int32PtrTy = VectorType::get(Int32PtrTy, 2);
+  Type *V4Int32PtrTy = VectorType::get(Int32PtrTy, 4);
 
   const Constant* c8 = Constant::getNullValue(V8x8Ty);
   const Constant* c64 = Constant::getNullValue(V8x64Ty);
@@ -205,6 +206,21 @@ TEST(InstructionsTest, CastInst) {
   EXPECT_FALSE(CastInst::isBitCastable(V2Int64Ty, V2Int32Ty));
 
 
+  EXPECT_FALSE(CastInst::castIsValid(Instruction::BitCast,
+                                     Constant::getNullValue(V4Int32PtrTy),
+                                     V2Int32PtrTy));
+  EXPECT_FALSE(CastInst::castIsValid(Instruction::BitCast,
+                                     Constant::getNullValue(V2Int32PtrTy),
+                                     V4Int32PtrTy));
+
+  EXPECT_FALSE(CastInst::castIsValid(Instruction::AddrSpaceCast,
+                                     Constant::getNullValue(V4Int32PtrAS1Ty),
+                                     V2Int32PtrTy));
+  EXPECT_FALSE(CastInst::castIsValid(Instruction::AddrSpaceCast,
+                                     Constant::getNullValue(V2Int32PtrTy),
+                                     V4Int32PtrAS1Ty));
+
+
   // Check that assertion is not hit when creating a cast with a vector of
   // pointers
   // First form