diff --git a/tools/SourceKit/lib/SwiftLang/SwiftASTManager.cpp b/tools/SourceKit/lib/SwiftLang/SwiftASTManager.cpp
index 1e2b1fd10a211..1ebbcfeb25441 100644
--- a/tools/SourceKit/lib/SwiftLang/SwiftASTManager.cpp
+++ b/tools/SourceKit/lib/SwiftLang/SwiftASTManager.cpp
@@ -539,6 +539,11 @@ bool SwiftASTManager::initCompilerInvocation(
   // We don't care about LLVMArgs
   FrontendOpts.LLVMArgs.clear();
 
+  // This validation may call stat(2) many times. Disable it to prevent
+  // performance issues.
+  Invocation.getSearchPathOptions().DisableModulesValidateSystemDependencies =
+      true;
+
   // SwiftSourceInfo files provide source location information for decls coming
   // from loaded modules. For most IDE use cases it either has an undesirable
   // impact on performance with no benefit (code completion), results in stale
diff --git a/tools/swift-ide-test/swift-ide-test.cpp b/tools/swift-ide-test/swift-ide-test.cpp
index d04bd53dab5f0..1b742281b9dfd 100644
--- a/tools/swift-ide-test/swift-ide-test.cpp
+++ b/tools/swift-ide-test/swift-ide-test.cpp
@@ -3302,6 +3302,8 @@ int main(int argc, char *argv[]) {
     options::DebugForbidTypecheckPrefix;
   InitInvok.getTypeCheckerOptions().DebugConstraintSolver =
       options::DebugConstraintSolver;
+  InitInvok.getSearchPathOptions().DisableModulesValidateSystemDependencies =
+      true;
 
   for (auto ConfigName : options::BuildConfigs)
     InitInvok.getLangOptions().addCustomConditionalCompilationFlag(ConfigName);