Index: clang/lib/Driver/ToolChains/Clang.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Clang.cpp
+++ clang/lib/Driver/ToolChains/Clang.cpp
@@ -3772,6 +3772,10 @@
     Args.ClaimAllArgs(options::OPT_fmodules_disable_diagnostic_validation);
   }
 
+  // Claim `-fmodule-output` and `-fmodule-output=` to avoid unused warnings.
+  Args.ClaimAllArgs(options::OPT_fmodule_output);
+  Args.ClaimAllArgs(options::OPT_fmodule_output_EQ);
+
   return HaveModules;
 }
 
Index: clang/test/Driver/module-output.cppm
===================================================================
--- clang/test/Driver/module-output.cppm
+++ clang/test/Driver/module-output.cppm
@@ -6,6 +6,9 @@
 // Tests that the .pcm file will be generated in the same path with the specified one in the comamnd line.
 // RUN: %clang -std=c++20 %s -fmodule-output=%t/pcm/Hello.pcm -o %t/Hello.o \
 // RUN:   -c -### 2>&1 | FileCheck %s --check-prefix=CHECK-SPECIFIED
+//
+// RUN: %clang -std=c++20 %s -fmodule-output=Hello.pcm -fmodule-output -c -fsyntax-only \
+// RUN:   -### 2>&1 | FileCheck %s --check-prefix=CHECK-NOT-USED
 
 export module Hello;
 
@@ -13,3 +16,7 @@
 // CHECK: "-emit-obj" {{.*}}"-main-file-name" "module-output.cppm" {{.*}}"-o" "{{.*}}/Hello.o" "-x" "pcm" "{{.*}}/Hello.pcm"
 // CHECK-SPECIFIED: "-emit-module-interface" {{.*}}"-main-file-name" "module-output.cppm" {{.*}}"-o" "{{.*}}/Hello.pcm" "-x" "c++" "{{.*}}/module-output.cppm"
 // CHECK-SPECIFIED: "-emit-obj" {{.*}}"-main-file-name" "module-output.cppm" {{.*}}"-o" "{{.*}}/Hello.o" "-x" "pcm" "{{.*}}/Hello.pcm"
+// CHECK-NOT-USED-NOT: warning: argument unused during compilation: '-fmodule-output' 
+// CHECK-NOT-USED-NOT: warning: argument unused during compilation: '-fmodule-output=Hello.pcm' 
+// CHECK-NOT-USED-NOT: "-fmodule-output"
+// CHECK-NOT-USED-NOT: "-fmodule-output="