diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 4e6d7bb16f51b..fd6c250efeda2 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -3163,8 +3163,8 @@ static bool ParseHeaderSearchArgs(HeaderSearchOptions &Opts, ArgList &Args,
     StringRef Val = A->getValue();
     if (Val.contains('=')) {
       auto Split = Val.split('=');
-      Opts.PrebuiltModuleFiles.insert(
-          {std::string(Split.first), std::string(Split.second)});
+      Opts.PrebuiltModuleFiles.insert_or_assign(
+          std::string(Split.first), std::string(Split.second));
     }
   }
   for (const auto *A : Args.filtered(OPT_fprebuilt_module_path))
diff --git a/clang/test/Modules/duplicated-module-file-eq-module-name.cppm b/clang/test/Modules/duplicated-module-file-eq-module-name.cppm
new file mode 100644
index 0000000000000..e86dbe2b941ef
--- /dev/null
+++ b/clang/test/Modules/duplicated-module-file-eq-module-name.cppm
@@ -0,0 +1,21 @@
+// Tests that we will pick the last `-fmodule-file=<module-name>=<path>` flag
+// for <module-name>.
+
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+// RUN: cd %t
+//
+// RUN: %clang_cc1 -std=c++20 %t/a.cppm -emit-module-interface -o %t/a.pcm
+// RUN: %clang_cc1 -std=c++20 %t/u.cpp -fmodule-file=a=%t/unexist.pcm \
+// RUN:      -fmodule-file=a=%t/a.pcm -verify -fsyntax-only
+
+//--- a.cppm
+export module a;
+export int a();
+
+//--- u.cpp
+// expected-no-diagnostics
+import a;
+int u() {
+    return a();
+}