diff --git a/mlir/lib/Dialect/SPIRV/SPIRVOps.cpp b/mlir/lib/Dialect/SPIRV/SPIRVOps.cpp
--- a/mlir/lib/Dialect/SPIRV/SPIRVOps.cpp
+++ b/mlir/lib/Dialect/SPIRV/SPIRVOps.cpp
@@ -1955,8 +1955,13 @@
   // SPIR-V spec: "Storage Class is the Storage Class of the memory holding the
   // object. It cannot be Generic. It must be the same as the Storage Class
   // operand of the Result Type."
-  if (varOp.storageClass() == spirv::StorageClass::Generic)
-    return varOp.emitOpError("storage class cannot be 'Generic'");
+  // Also, Function storage class is reserved by spv.Variable.
+  auto storageClass = varOp.storageClass();
+  if (storageClass == spirv::StorageClass::Generic ||
+      storageClass == spirv::StorageClass::Function) {
+    return varOp.emitOpError("storage class cannot be '")
+           << stringifyStorageClass(storageClass) << "'";
+  }
 
   if (auto init =
           varOp.getAttrOfType<FlatSymbolRefAttr>(kInitializerAttrName)) {
diff --git a/mlir/test/Dialect/SPIRV/structure-ops.mlir b/mlir/test/Dialect/SPIRV/structure-ops.mlir
--- a/mlir/test/Dialect/SPIRV/structure-ops.mlir
+++ b/mlir/test/Dialect/SPIRV/structure-ops.mlir
@@ -347,6 +347,13 @@
 
 // -----
 
+spv.module Logical GLSL450 {
+  // expected-error @+1 {{storage class cannot be 'Function'}}
+  spv.globalVariable @var0 : !spv.ptr<f32, Function>
+}
+
+// -----
+
 spv.module Logical GLSL450 {
   spv.func @foo() "None" {
     // expected-error @+1 {{op must appear in a module-like op's block}}