Index: include/clang/Basic/CodeGenOptions.def
===================================================================
--- include/clang/Basic/CodeGenOptions.def
+++ include/clang/Basic/CodeGenOptions.def
@@ -109,6 +109,7 @@
 
 CODEGENOPT(InstrumentForProfiling , 1, 0) ///< Set when -pg is enabled.
 CODEGENOPT(CallFEntry , 1, 0) ///< Set when -mfentry is enabled.
+CODEGENOPT(MNopMCount , 1, 0) ///< Set when -mnop-mcount is enabled.
 CODEGENOPT(LessPreciseFPMAD  , 1, 0) ///< Enable less precise MAD instructions to
                                      ///< be generated.
 CODEGENOPT(PrepareForLTO     , 1, 0) ///< Set when -flto is enabled on the
Index: include/clang/Driver/Options.td
===================================================================
--- include/clang/Driver/Options.td
+++ include/clang/Driver/Options.td
@@ -2383,6 +2383,8 @@
 def mno_pie_copy_relocations : Flag<["-"], "mno-pie-copy-relocations">, Group<m_Group>;
 def mfentry : Flag<["-"], "mfentry">, HelpText<"Insert calls to fentry at function entry (x86 only)">,
   Flags<[CC1Option]>, Group<m_Group>;
+def mnop_mcount : Flag<["-"], "mnop-mcount">, HelpText<"Generate mcount/__fentry__ calls as nops. To activate they need to be patched in.">,
+  Flags<[CC1Option]>, Group<m_Group>;
 def mips16 : Flag<["-"], "mips16">, Group<m_mips_Features_Group>;
 def mno_mips16 : Flag<["-"], "mno-mips16">, Group<m_mips_Features_Group>;
 def mmicromips : Flag<["-"], "mmicromips">, Group<m_mips_Features_Group>;
Index: lib/CodeGen/CodeGenFunction.cpp
===================================================================
--- lib/CodeGen/CodeGenFunction.cpp
+++ lib/CodeGen/CodeGenFunction.cpp
@@ -889,6 +889,8 @@
         Fn->addFnAttr("instrument-function-entry-inlined",
                       getTarget().getMCountName());
       }
+      if (CGM.getCodeGenOpts().MNopMCount)
+        Fn->addFnAttr("mnop-mcount", "true");
     }
   }
 
Index: lib/Driver/ToolChains/Clang.cpp
===================================================================
--- lib/Driver/ToolChains/Clang.cpp
+++ lib/Driver/ToolChains/Clang.cpp
@@ -4688,6 +4688,9 @@
   if (TC.SupportsProfiling())
     Args.AddLastArg(CmdArgs, options::OPT_mfentry);
 
+  if (TC.SupportsProfiling())
+    Args.AddLastArg(CmdArgs, options::OPT_mnop_mcount);
+
   if (Args.getLastArg(options::OPT_fapple_kext) ||
       (Args.hasArg(options::OPT_mkernel) && types::isCXX(InputType)))
     CmdArgs.push_back("-fapple-kext");
Index: lib/Frontend/CompilerInvocation.cpp
===================================================================
--- lib/Frontend/CompilerInvocation.cpp
+++ lib/Frontend/CompilerInvocation.cpp
@@ -1092,6 +1092,7 @@
 
   Opts.InstrumentForProfiling = Args.hasArg(OPT_pg);
   Opts.CallFEntry = Args.hasArg(OPT_mfentry);
+  Opts.MNopMCount = Args.hasArg(OPT_mnop_mcount);
   Opts.EmitOpenCLArgMetadata = Args.hasArg(OPT_cl_kernel_arg_info);
 
   if (const Arg *A = Args.getLastArg(OPT_fcf_protection_EQ)) {
Index: test/CodeGen/mnop-mcount.c
===================================================================
--- /dev/null
+++ test/CodeGen/mnop-mcount.c
@@ -0,0 +1,18 @@
+// RUN: %clang_cc1 -pg -mfentry -mnop-mcount -triple s390x-ibm-linux -emit-llvm -o - %s | FileCheck  %s
+// RUN: %clang_cc1 -pg -mnop-mcount -triple s390x-ibm-linux -emit-llvm -o - %s | FileCheck  %s
+// RUN: %clang_cc1 -mfentry -mnop-mcount -triple s390x-ibm-linux -emit-llvm -o - %s | FileCheck -check-prefix=NOPG %s
+// RUN: %clang_cc1 -mnop-mcount -triple s390x-ibm-linux -emit-llvm -o - %s | FileCheck -check-prefix=NOPG %s
+
+int foo(void) {
+  return 0;
+}
+
+int __attribute__((no_instrument_function)) no_instrument(void) {
+  return foo();
+}
+
+//CHECK: attributes #0 = { {{.*}}"mnop-mcount"="true"{{.*}} }
+//CHECK: attributes #1 = { {{.*}} }
+//CHECK-NOT: attributes #1 = { {{.*}}"mnop-mcount"="true"{{.*}} }
+//NOPG-NOT: attributes #0 = { {{.*}}"mnop-mcount"{{.*}} }
+//NOPG-NOT: attributes #1 = { {{.*}}"mnop-mcount"{{.*}} }