Add fast path for ValueOf, ReflectValueOf

schema/field.go

@@ -465,6 +465,14 @@ func (field *Field) setupValuerAndSetter() {
 	}
 
 	// ValueOf returns field's value and if it is zero
+	fieldIndex := field.StructField.Index[0]
+	switch {
+	case len(field.StructField.Index) == 1 && fieldIndex > 0:
+		field.ValueOf = func(ctx context.Context, value reflect.Value) (interface{}, bool) {
+			fieldValue := reflect.Indirect(value).Field(fieldIndex)
+			return fieldValue.Interface(), fieldValue.IsZero()
+		}
+	default:
 		field.ValueOf = func(ctx context.Context, v reflect.Value) (interface{}, bool) {
 			v = reflect.Indirect(v)
 			for _, fieldIdx := range field.StructField.Index {
@@ -484,6 +492,7 @@ func (field *Field) setupValuerAndSetter() {
 			fv, zero := v.Interface(), v.IsZero()
 			return fv, zero
 		}
+	}
 
 	if field.Serializer != nil {
 		oldValuerOf := field.ValueOf
@@ -509,6 +518,12 @@ func (field *Field) setupValuerAndSetter() {
 	}
 
 	// ReflectValueOf returns field's reflect value
+	switch {
+	case len(field.StructField.Index) == 1 && fieldIndex > 0:
+		field.ReflectValueOf = func(ctx context.Context, value reflect.Value) reflect.Value {
+			return reflect.Indirect(value).Field(fieldIndex)
+		}
+	default:
 		field.ReflectValueOf = func(ctx context.Context, v reflect.Value) reflect.Value {
 			v = reflect.Indirect(v)
 			for idx, fieldIdx := range field.StructField.Index {
@@ -528,6 +543,7 @@ func (field *Field) setupValuerAndSetter() {
 			}
 			return v
 		}
+	}
 
 	fallbackSetter := func(ctx context.Context, value reflect.Value, v interface{}, setter func(context.Context, reflect.Value, interface{}) error) (err error) {
 		if v == nil {

tests/go.mod

@@ -3,6 +3,7 @@ module gorm.io/gorm/tests
 go 1.14
 
 require (
+	github.com/golang-sql/civil v0.0.0-20220223132316-b832511892a9 // indirect
 	github.com/google/uuid v1.3.0
 	github.com/jackc/pgx/v4 v4.15.0 // indirect
 	github.com/jinzhu/now v1.1.4