diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp
--- a/clang/lib/CodeGen/CGDecl.cpp
+++ b/clang/lib/CodeGen/CGDecl.cpp
@@ -1050,13 +1050,13 @@
   llvm::Type *OrigTy = constant->getType();
   if (const auto STy = dyn_cast<llvm::StructType>(OrigTy))
     return constStructWithPadding(CGM, isPattern, STy, constant);
-  if (auto *STy = dyn_cast<llvm::SequentialType>(OrigTy)) {
+  if (auto *ArrayTy = dyn_cast<llvm::ArrayType>(OrigTy)) {
     llvm::SmallVector<llvm::Constant *, 8> Values;
-    unsigned Size = STy->getNumElements();
+    uint64_t Size = ArrayTy->getNumElements();
     if (!Size)
       return constant;
-    llvm::Type *ElemTy = STy->getElementType();
-    bool ZeroInitializer = constant->isZeroValue();
+    llvm::Type *ElemTy = ArrayTy->getElementType();
+    bool ZeroInitializer = constant->isNullValue();
     llvm::Constant *OpValue, *PaddedOp;
     if (ZeroInitializer) {
       OpValue = llvm::Constant::getNullValue(ElemTy);
@@ -1072,13 +1072,10 @@
     auto *NewElemTy = Values[0]->getType();
     if (NewElemTy == ElemTy)
       return constant;
-    if (OrigTy->isArrayTy()) {
-      auto *ArrayTy = llvm::ArrayType::get(NewElemTy, Size);
-      return llvm::ConstantArray::get(ArrayTy, Values);
-    } else {
-      return llvm::ConstantVector::get(Values);
-    }
+    auto *NewArrayTy = llvm::ArrayType::get(NewElemTy, Size);
+    return llvm::ConstantArray::get(NewArrayTy, Values);
   }
+  // FIXME: Do we need to handle tail padding in vectors?
   return constant;
 }
 
diff --git a/clang/test/CodeGenCXX/auto-var-init.cpp b/clang/test/CodeGenCXX/auto-var-init.cpp
--- a/clang/test/CodeGenCXX/auto-var-init.cpp
+++ b/clang/test/CodeGenCXX/auto-var-init.cpp
@@ -1610,5 +1610,24 @@
 // CHECK-NEXT:  store <4 x double> <double 0x400921FB54442D18, double 0x400921FB54442D18, double 0x400921FB54442D18, double 0x400921FB54442D18>, <4 x double>* %custom, align [[ALIGN]]
 // CHECK-NEXT:  call void @{{.*}}used{{.*}}%custom)
 
+// TODO: This vector has tail padding
+TEST_UNINIT(doublevec24, double  __attribute__((vector_size(24))));
+// CHECK-LABEL: @test_doublevec24_uninit()
+// CHECK:       %uninit = alloca <3 x double>, align
+// CHECK-NEXT:  call void @{{.*}}used{{.*}}%uninit)
+// PATTERN-LABEL: @test_doublevec24_uninit()
+// PATTERN: store <3 x double> <double 0xFFFFFFFFFFFFFFFF, double 0xFFFFFFFFFFFFFFFF, double 0xFFFFFFFFFFFFFFFF>, <3 x double>* %uninit, align 32
+// ZERO-LABEL: @test_doublevec24_uninit()
+// ZERO: store <3 x double> zeroinitializer, <3 x double>* %uninit, align 32
+
+// TODO: This vector has tail padding
+TEST_UNINIT(longdoublevec32, long double  __attribute__((vector_size(sizeof(long double)*2))));
+// CHECK-LABEL: @test_longdoublevec32_uninit()
+// CHECK:       %uninit = alloca <2 x x86_fp80>, align
+// CHECK-NEXT:  call void @{{.*}}used{{.*}}%uninit)
+// PATTERN-LABEL: @test_longdoublevec32_uninit()
+// PATTERN: store <2 x x86_fp80> <x86_fp80 0xKFFFFFFFFFFFFFFFFFFFF, x86_fp80 0xKFFFFFFFFFFFFFFFFFFFF>, <2 x x86_fp80>* %uninit, align 32
+// ZERO-LABEL: @test_longdoublevec32_uninit()
+// ZERO: store <2 x x86_fp80> zeroinitializer, <2 x x86_fp80>* %uninit, align 32
 
 } // extern "C"