diff --git a/benchmark/Package.swift b/benchmark/Package.swift
index 6ec0abb2b37..32afaae13b4 100644
--- a/benchmark/Package.swift
+++ b/benchmark/Package.swift
@@ -185,10 +185,15 @@ targets += multiSourceLibraries.map { lib in
 // Top Level Definition
 //
 
-let p = Package(
+var p = Package(
   name: "swiftbench",
   products: products,
   targets: targets,
   swiftLanguageVersions: [.v4],
   cxxLanguageStandard: .cxx20
 )
+
+// Let's build for Swift 5.5-aligned runtimes.
+#if os(macOS) || os(iOS) || os(watchOS) || os(tvOS)
+p.platforms = [.macOS(.v12), .iOS(.v15), .watchOS(.v8), .tvOS(.v15)]
+#endif