diff --git a/libs/vkd3d-shader/ir.c b/libs/vkd3d-shader/ir.c
index 03813656..76987310 100644
--- a/libs/vkd3d-shader/ir.c
+++ b/libs/vkd3d-shader/ir.c
@@ -1502,6 +1502,10 @@ static void vsir_validate_register(struct validation_context *ctx,
     if (reg->precision >= VKD3D_SHADER_REGISTER_PRECISION_COUNT)
         validator_error(ctx, VKD3D_SHADER_ERROR_VSIR_INVALID_PRECISION, "Invalid register precision %#x.",
                 reg->precision);
+
+    if (reg->data_type >= VKD3D_DATA_COUNT)
+        validator_error(ctx, VKD3D_SHADER_ERROR_VSIR_INVALID_DATA_TYPE, "Invalid register data type %#x.",
+                reg->data_type);
 }
 
 static void vsir_validate_dst_param(struct validation_context *ctx,
diff --git a/libs/vkd3d-shader/vkd3d_shader_private.h b/libs/vkd3d-shader/vkd3d_shader_private.h
index 6bb0882e..4c483520 100644
--- a/libs/vkd3d-shader/vkd3d_shader_private.h
+++ b/libs/vkd3d-shader/vkd3d_shader_private.h
@@ -201,6 +201,7 @@ enum vkd3d_shader_error
     VKD3D_SHADER_ERROR_VSIR_INVALID_SHIFT               = 9005,
     VKD3D_SHADER_ERROR_VSIR_INVALID_SWIZZLE             = 9006,
     VKD3D_SHADER_ERROR_VSIR_INVALID_PRECISION           = 9007,
+    VKD3D_SHADER_ERROR_VSIR_INVALID_DATA_TYPE           = 9008,
 };
 
 enum vkd3d_shader_opcode
@@ -580,6 +581,8 @@ enum vkd3d_data_type
     VKD3D_DATA_UINT8,
     VKD3D_DATA_UINT64,
     VKD3D_DATA_BOOL,
+
+    VKD3D_DATA_COUNT,
 };
 
 static inline bool data_type_is_integer(enum vkd3d_data_type data_type)