diff --git a/clang/lib/Driver/ToolChains/Arch/PPC.h b/clang/lib/Driver/ToolChains/Arch/PPC.h
--- a/clang/lib/Driver/ToolChains/Arch/PPC.h
+++ b/clang/lib/Driver/ToolChains/Arch/PPC.h
@@ -35,7 +35,7 @@
 
 FloatABI getPPCFloatABI(const Driver &D, const llvm::opt::ArgList &Args);
 
-std::string getPPCTargetCPU(const llvm::opt::ArgList &Args,
+std::string getPPCTargetCPU(const Driver &D, const llvm::opt::ArgList &Args,
                             const llvm::Triple &T);
 const char *getPPCAsmModeForCPU(StringRef Name);
 ReadGOTPtrMode getPPCReadGOTPtrMode(const Driver &D, const llvm::Triple &Triple,
diff --git a/clang/lib/Driver/ToolChains/Arch/PPC.cpp b/clang/lib/Driver/ToolChains/Arch/PPC.cpp
--- a/clang/lib/Driver/ToolChains/Arch/PPC.cpp
+++ b/clang/lib/Driver/ToolChains/Arch/PPC.cpp
@@ -35,7 +35,13 @@
 }
 
 /// getPPCTargetCPU - Get the (LLVM) name of the PowerPC cpu we are targeting.
-std::string ppc::getPPCTargetCPU(const ArgList &Args, const llvm::Triple &T) {
+std::string ppc::getPPCTargetCPU(const Driver &D, const ArgList &Args,
+                                 const llvm::Triple &T) {
+  if (const Arg *A = Args.getLastArg(clang::driver::options::OPT_march_EQ)) {
+    D.Diag(diag::err_drv_unsupported_opt_for_target)
+        << A->getSpelling() << T.getTriple();
+  }
+
   if (Arg *A = Args.getLastArg(clang::driver::options::OPT_mcpu_EQ)) {
     StringRef CPUName = A->getValue();
 
diff --git a/clang/lib/Driver/ToolChains/CommonArgs.cpp b/clang/lib/Driver/ToolChains/CommonArgs.cpp
--- a/clang/lib/Driver/ToolChains/CommonArgs.cpp
+++ b/clang/lib/Driver/ToolChains/CommonArgs.cpp
@@ -410,7 +410,7 @@
   case llvm::Triple::ppcle:
   case llvm::Triple::ppc64:
   case llvm::Triple::ppc64le:
-    return ppc::getPPCTargetCPU(Args, T);
+    return ppc::getPPCTargetCPU(D, Args, T);
 
   case llvm::Triple::csky:
     if (const Arg *A = Args.getLastArg(options::OPT_mcpu_EQ))
diff --git a/clang/test/Driver/ppc-cpus.c b/clang/test/Driver/ppc-cpus.c
--- a/clang/test/Driver/ppc-cpus.c
+++ b/clang/test/Driver/ppc-cpus.c
@@ -37,3 +37,6 @@
 // RUN: %clang -### -c -target powerpc64 %s -mcpu=405     2>&1 | FileCheck %s --check-prefix=GENERIC
 //
 // GENERIC: "-target-cpu" "ppc64"
+
+// RUN: %clang -### -c --target=powerpc64 %s -march=generic 2>&1 | FileCheck --check-prefix=MARCH %s
+// MARCH: error: unsupported option '-march=' for target 'powerpc64'