Index: clang/lib/CodeGen/BackendUtil.cpp
===================================================================
--- clang/lib/CodeGen/BackendUtil.cpp
+++ clang/lib/CodeGen/BackendUtil.cpp
@@ -1312,7 +1312,9 @@
                                            /*DropTypeTests=*/true));
           });
 
-    if (Level != PassBuilder::OptimizationLevel::O0) {
+    if (CodeGenOpts.InstrumentFunctions ||
+        CodeGenOpts.InstrumentFunctionsAfterInlining ||
+        CodeGenOpts.InstrumentFunctionEntryBare) {
       PB.registerPipelineStartEPCallback(
           [](ModulePassManager &MPM, PassBuilder::OptimizationLevel Level) {
             MPM.addPass(createModuleToFunctionPassAdaptor(
Index: llvm/include/llvm/Transforms/Utils/EntryExitInstrumenter.h
===================================================================
--- llvm/include/llvm/Transforms/Utils/EntryExitInstrumenter.h
+++ llvm/include/llvm/Transforms/Utils/EntryExitInstrumenter.h
@@ -19,8 +19,6 @@
 
 namespace llvm {
 
-class Function;
-
 struct EntryExitInstrumenterPass
     : public PassInfoMixin<EntryExitInstrumenterPass> {
   EntryExitInstrumenterPass(bool PostInlining) : PostInlining(PostInlining) {}
@@ -28,6 +26,8 @@
   PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
 
   bool PostInlining;
+
+  static bool isRequired() { return true; }
 };
 
 } // namespace llvm
Index: llvm/test/Transforms/EntryExitInstrumenter/mcount.ll
===================================================================
--- llvm/test/Transforms/EntryExitInstrumenter/mcount.ll
+++ llvm/test/Transforms/EntryExitInstrumenter/mcount.ll
@@ -1,4 +1,7 @@
-; RUN: opt -passes="function(ee-instrument),cgscc(inline),function(post-inline-ee-instrument)" -S < %s | FileCheck %s
+; RUN: opt --O0 --ee-instrument --inline --post-inline-ee-instrument -S < %s | FileCheck %s
+
+; Check if the pass is enabbled on both -O0 and higher optimization levels
+; RUN: opt --O2 --ee-instrument --post-inline-ee-instrument -S < %s | FileCheck --check-prefix=OPT %s
 
 ; Running the passes twice should not result in more instrumentation.
 ; RUN: opt -passes="function(ee-instrument),function(ee-instrument),cgscc(inline),function(post-inline-ee-instrument),function(post-inline-ee-instrument)" -S < %s | FileCheck %s
@@ -18,6 +21,15 @@
 ; CHECK-NEXT: %1 = call i8* @llvm.returnaddress(i32 0)
 ; CHECK-NEXT: call void @__cyg_profile_func_exit(i8* bitcast (void ()* @leaf_function to i8*), i8* %1)
 ; CHECK-NEXT: ret void
+
+; OPT-LABEL: define void @leaf_function()
+; OPT: entry:
+; OPT-NEXT: call void @mcount()
+; OPT-NEXT: %0 = call i8* @llvm.returnaddress(i32 0)
+; OPT-NEXT: call void @__cyg_profile_func_enter(i8* bitcast (void ()* @leaf_function to i8*), i8* %0)
+; OPT-NEXT: %1 = call i8* @llvm.returnaddress(i32 0)
+; OPT-NEXT: call void @__cyg_profile_func_exit(i8* bitcast (void ()* @leaf_function to i8*), i8* %1)
+; OPT-NEXT: ret void
 }
 
 
@@ -42,6 +54,16 @@
 
 ; CHECK-NEXT: call void @__cyg_profile_func_exit(i8* bitcast (void ()* @root_function to i8*), i8* %3)
 ; CHECK-NEXT: ret void
+
+; OPT-LABEL: define void @root_function()
+; OPT: entry:
+; OPT-NEXT: call void @mcount()
+
+; OPT-NEXT: %0 = call i8* @llvm.returnaddress(i32 0)
+; OPT-NEXT: call void @__cyg_profile_func_enter(i8* bitcast (void ()* @root_function to i8*), i8* %0)
+; OPT-NEXT: %1 = call i8* @llvm.returnaddress(i32 0)
+; OPT-NEXT: call void @__cyg_profile_func_exit(i8* bitcast (void ()* @root_function to i8*), i8* %1)
+; OPT-NEXT: ret void
 }