diff --git a/Package.swift b/Package.swift
index daca480..093adeb 100644
--- a/Package.swift
+++ b/Package.swift
@@ -33,6 +33,7 @@ let package = Package(
             swiftSettings: [
                 .unsafeFlags(["-Xfrontend", "-warn-long-function-bodies=100"], .when(configuration: .debug)),
                 .unsafeFlags(["-Xfrontend", "-warn-long-expression-type-checking=100"], .when(configuration: .debug)),
+                .unsafeFlags(["-cross-module-optimization"]),
                 .enableExperimentalFeature("CodeItemMacros"),
                 .enableUpcomingFeature("ExistentialAny"),
                 .enableUpcomingFeature("InternalImportsByDefault"),
@@ -46,6 +47,7 @@ let package = Package(
             swiftSettings: [
                 .unsafeFlags(["-Xfrontend", "-warn-long-function-bodies=100"], .when(configuration: .debug)),
                 .unsafeFlags(["-Xfrontend", "-warn-long-expression-type-checking=100"], .when(configuration: .debug)),
+                .unsafeFlags(["-cross-module-optimization"]),
                 .enableUpcomingFeature("ExistentialAny"),
                 .enableUpcomingFeature("InternalImportsByDefault"),
             ]
@@ -59,6 +61,7 @@ let package = Package(
             swiftSettings: [
                 .unsafeFlags(["-Xfrontend", "-warn-long-function-bodies=100"], .when(configuration: .debug)),
                 .unsafeFlags(["-Xfrontend", "-warn-long-expression-type-checking=100"], .when(configuration: .debug)),
+                .unsafeFlags(["-cross-module-optimization"]),
                 .enableUpcomingFeature("ExistentialAny"),
                 .enableUpcomingFeature("InternalImportsByDefault"),
             ]