diff --git a/llvm/lib/Target/DirectX/DXILIntrinsicExpansion.cpp b/llvm/lib/Target/DirectX/DXILIntrinsicExpansion.cpp
index 501231298ed25a..ac85859af8a53e 100644
--- a/llvm/lib/Target/DirectX/DXILIntrinsicExpansion.cpp
+++ b/llvm/lib/Target/DirectX/DXILIntrinsicExpansion.cpp
@@ -171,8 +171,9 @@ static bool expandLengthIntrinsic(CallInst *Orig) {
   Value *Elt = Builder.CreateExtractElement(X, (uint64_t)0);
   auto *XVec = dyn_cast<FixedVectorType>(Ty);
   unsigned XVecSize = XVec->getNumElements();
-  assert(Ty->isVectorTy() && XVecSize > 1 &&
-         "dx.length requires a vector of length 2 or more");
+  if (!(Ty->isVectorTy() && XVecSize > 1))
+    report_fatal_error(Twine("Invalid input type for length intrinsic"),
+                       /* gen_crash_diag=*/false);
 
   Value *Sum = Builder.CreateFMul(Elt, Elt);
   for (unsigned I = 1; I < XVecSize; I++) {
diff --git a/llvm/test/CodeGen/DirectX/length_invalid_intrinsic_error.ll b/llvm/test/CodeGen/DirectX/length_invalid_intrinsic_error.ll
index ac3a0513eb6b27..277fbaa462b0fa 100644
--- a/llvm/test/CodeGen/DirectX/length_invalid_intrinsic_error.ll
+++ b/llvm/test/CodeGen/DirectX/length_invalid_intrinsic_error.ll
@@ -1,10 +1,10 @@
 ; RUN: not opt -S -dxil-op-lower -mtriple=dxil-pc-shadermodel6.3-library %s 2>&1 | FileCheck %s
 
-; DXIL operation length does not support scalar types
-; CHECK: error: invalid intrinsic signature
+; DXIL operation length does not support 1-element vector types.
+; CHECK: LLVM ERROR: Invalid input type for length intrinsic
 
-define noundef float @test_length_float(float noundef %p0) {
+define noundef float @test_length_float(<1 x float> noundef %p0) {
 entry:
-  %hlsl.length = call float @llvm.dx.length.f32(float %p0)
+  %hlsl.length = call float @llvm.dx.length.v1f32(<1 x float> %p0)
   ret float %hlsl.length
 }
diff --git a/llvm/test/CodeGen/DirectX/length_invalid_intrinsic_error_scalar.ll b/llvm/test/CodeGen/DirectX/length_invalid_intrinsic_error_scalar.ll
new file mode 100644
index 00000000000000..ac3a0513eb6b27
--- /dev/null
+++ b/llvm/test/CodeGen/DirectX/length_invalid_intrinsic_error_scalar.ll
@@ -0,0 +1,10 @@
+; RUN: not opt -S -dxil-op-lower -mtriple=dxil-pc-shadermodel6.3-library %s 2>&1 | FileCheck %s
+
+; DXIL operation length does not support scalar types
+; CHECK: error: invalid intrinsic signature
+
+define noundef float @test_length_float(float noundef %p0) {
+entry:
+  %hlsl.length = call float @llvm.dx.length.f32(float %p0)
+  ret float %hlsl.length
+}