Merge pull request swiftlang#23805 from apple/revert-23725-optifreeze

Revert "[ParseableInterfaces] Stop explicitly optimizing cached modules"

Author: rintaro

lib/Frontend/ParseableInterfaceModuleLoader.cpp

@@ -520,6 +520,10 @@ class swift::ParseableInterfaceBuilder {
         return;
       }
 
+      // Optimize emitted modules. This has to happen after we parse arguments,
+      // because parseSILOpts would override the current optimization mode.
+      subInvocation.getSILOptions().OptMode = OptimizationMode::ForSpeed;
+
       // Build the .swiftmodule; this is a _very_ abridged version of the logic
       // in performCompile in libFrontendTool, specialized, to just the one
       // module-serialization task we're trying to do here.

test/ParseableInterface/optimization-level.swift

@@ -30,6 +30,6 @@ func f(s : inout [Int]) {
 // Test we can generate the interface of a module loaded via a .swiftinterface file correctly
 
 // RUN: %empty-directory(%t.mod)
-// RUN: %swift -emit-module -o /dev/null -emit-parseable-module-interface-path %t.mod/swift_mod.swiftinterface -O %S/Inputs/swift_mod.swift -parse-as-library
+// RUN: %swift -emit-module -o /dev/null -emit-parseable-module-interface-path %t.mod/swift_mod.swiftinterface %S/Inputs/swift_mod.swift -parse-as-library
 // RUN: %sourcekitd-test -req=interface-gen -module swift_mod -- -I %t.mod -module-cache-path %t.mod/mcp > %t.response
 // RUN: diff -u %s.from_swiftinterface.response %t.response