diff --git a/llvm/include/llvm/IR/InstrTypes.h b/llvm/include/llvm/IR/InstrTypes.h
--- a/llvm/include/llvm/IR/InstrTypes.h
+++ b/llvm/include/llvm/IR/InstrTypes.h
@@ -1723,6 +1723,9 @@
 
   /// Determine if the call cannot be tail merged.
   bool cannotMerge() const { return hasFnAttr(Attribute::NoMerge); }
+  void setCannotMerge() {
+    addAttribute(AttributeList::FunctionIndex, Attribute::NoMerge);
+  }
 
   /// Determine if the invoke is convergent
   bool isConvergent() const { return hasFnAttr(Attribute::Convergent); }
diff --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
--- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -693,7 +693,6 @@
   FunctionCallee AsanMemoryAccessCallbackSized[2][2];
 
   FunctionCallee AsanMemmove, AsanMemcpy, AsanMemset;
-  InlineAsm *EmptyAsm;
   Value *LocalDynamicShadow = nullptr;
   const GlobalsMetadata &GlobalsMD;
   DenseMap<const AllocaInst *, bool> ProcessedAllocas;
@@ -913,14 +912,12 @@
 
   bool HasNonEmptyInlineAsm = false;
   bool HasReturnsTwiceCall = false;
-  std::unique_ptr<CallInst> EmptyInlineAsm;
 
   FunctionStackPoisoner(Function &F, AddressSanitizer &ASan)
       : F(F), ASan(ASan), DIB(*F.getParent(), /*AllowUnresolved*/ false),
         C(ASan.C), IntptrTy(ASan.IntptrTy),
         IntptrPtrTy(PointerType::get(IntptrTy, 0)), Mapping(ASan.Mapping),
-        StackAlignment(1 << Mapping.Scale),
-        EmptyInlineAsm(CallInst::Create(ASan.EmptyAsm)) {}
+        StackAlignment(1 << Mapping.Scale) {}
 
   bool runOnFunction() {
     if (!ClStack) return false;
@@ -1082,9 +1079,8 @@
 
   void visitCallBase(CallBase &CB) {
     if (CallInst *CI = dyn_cast<CallInst>(&CB)) {
-      HasNonEmptyInlineAsm |= CI->isInlineAsm() &&
-                              !CI->isIdenticalTo(EmptyInlineAsm.get()) &&
-                              &CB != ASan.LocalDynamicShadow;
+      HasNonEmptyInlineAsm |=
+          CI->isInlineAsm() && &CB != ASan.LocalDynamicShadow;
       HasReturnsTwiceCall |= CI->canReturnTwice();
     }
   }
@@ -1621,10 +1617,7 @@
                             {Addr, ExpVal});
   }
 
-  // We don't do Call->setDoesNotReturn() because the BB already has
-  // UnreachableInst at the end.
-  // This EmptyAsm is required to avoid callback merge.
-  IRB.CreateCall(EmptyAsm, {});
+  Call->setCannotMerge();
   return Call;
 }
 
@@ -2598,10 +2591,6 @@
       M.getOrInsertFunction(kAsanPtrCmp, IRB.getVoidTy(), IntptrTy, IntptrTy);
   AsanPtrSubFunction =
       M.getOrInsertFunction(kAsanPtrSub, IRB.getVoidTy(), IntptrTy, IntptrTy);
-  // We insert an empty inline asm after __asan_report* to avoid callback merge.
-  EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
-                            StringRef(""), StringRef(""),
-                            /*hasSideEffects=*/true);
   if (Mapping.InGlobal)
     AsanShadowGlobal = M.getOrInsertGlobal("__asan_shadow",
                                            ArrayType::get(IRB.getInt8Ty(), 0));
diff --git a/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp b/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
--- a/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
@@ -595,9 +595,6 @@
 
   /// Branch weights for origin store.
   MDNode *OriginStoreWeights;
-
-  /// An empty volatile inline asm that prevents callback merge.
-  InlineAsm *EmptyAsm;
 };
 
 void insertModuleCtor(Module &M) {
@@ -854,10 +851,6 @@
   MemsetFn = M.getOrInsertFunction(
     "__msan_memset", IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IRB.getInt32Ty(),
     IntptrTy);
-  // We insert an empty inline asm after __msan_report* to avoid callback merge.
-  EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
-                            StringRef(""), StringRef(""),
-                            /*hasSideEffects=*/true);
 
   MsanInstrumentAsmStoreFn =
       M.getOrInsertFunction("__msan_instrument_asm_store", IRB.getVoidTy(),
@@ -1211,8 +1204,7 @@
     if (!Origin)
       Origin = (Value *)IRB.getInt32(0);
     assert(Origin->getType()->isIntegerTy());
-    IRB.CreateCall(MS.WarningFn, Origin);
-    IRB.CreateCall(MS.EmptyAsm, {});
+    IRB.CreateCall(MS.WarningFn, Origin)->setCannotMerge();
     // FIXME: Insert UnreachableInst if !MS.Recover?
     // This may invalidate some of the following checks and needs to be done
     // at the very end.
diff --git a/llvm/test/Instrumentation/MemorySanitizer/msan_basic.ll b/llvm/test/Instrumentation/MemorySanitizer/msan_basic.ll
--- a/llvm/test/Instrumentation/MemorySanitizer/msan_basic.ll
+++ b/llvm/test/Instrumentation/MemorySanitizer/msan_basic.ll
@@ -95,7 +95,6 @@
 ; CHECK: call void @__msan_warning_with_origin_noreturn(i32
 ; CHECK-ORIGINS-SAME %[[ORIGIN]])
 ; CHECK-CONT: 
-; CHECK-NEXT: call void asm sideeffect
 ; CHECK-NEXT: unreachable
 ; CHECK: br i1 %tobool
 ; CHECK: ret void