diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -3501,6 +3501,11 @@
   if (Args.hasArg(options::OPT_emit_interface_stubs)) {
     llvm::SmallVector<phases::ID, phases::MaxNumberOfPhases> PhaseList;
     if (Args.hasArg(options::OPT_c)) {
+      // Claim -emit-merged-ifs if we aren't going to invoke llvm-ifs.
+      // The intention of -emit-merged-ifs is to force llvm-ifs to generate text
+      // instead of a ifso. Perhaps this should be inverted.
+      if (Args.hasArg(options::OPT_emit_merged_ifs))
+        Args.ClaimAllArgs(options::OPT_emit_merged_ifs);
       llvm::SmallVector<phases::ID, phases::MaxNumberOfPhases> CompilePhaseList;
       types::getCompilationPhases(types::TY_IFS_CPP, CompilePhaseList);
       llvm::copy_if(CompilePhaseList, std::back_inserter(PhaseList),
diff --git a/clang/test/InterfaceStubs/warnings.c b/clang/test/InterfaceStubs/warnings.c
new file mode 100644
--- /dev/null
+++ b/clang/test/InterfaceStubs/warnings.c
@@ -0,0 +1,3 @@
+// RUN: %clang -emit-interface-stubs -emit-merged-ifs -c %s -o - 2>&1 | FileCheck %s
+// CHECK-NOT: warning: argument unused during compilation: '-emit-merged-ifs'
+int main() {}