diff --git a/llvm/lib/Target/AArch64/AArch64StackTagging.cpp b/llvm/lib/Target/AArch64/AArch64StackTagging.cpp
--- a/llvm/lib/Target/AArch64/AArch64StackTagging.cpp
+++ b/llvm/lib/Target/AArch64/AArch64StackTagging.cpp
@@ -334,6 +334,8 @@
       AU.addRequired<StackSafetyGlobalInfoWrapperPass>();
     if (MergeInit)
       AU.addRequired<AAResultsWrapperPass>();
+    AU.addRequired<PostDominatorTreeWrapperPass>();
+    AU.addRequired<DominatorTreeWrapperPass>();
   }
 };
 
@@ -345,6 +347,8 @@
                       false, false)
 INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
 INITIALIZE_PASS_DEPENDENCY(StackSafetyGlobalInfoWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(PostDominatorTreeWrapperPass)
 INITIALIZE_PASS_END(AArch64StackTagging, DEBUG_TYPE, "AArch64 Stack Tagging",
                     false, false)
 
@@ -503,31 +507,14 @@
   if (SInfo.AllocasToInstrument.empty())
     return false;
 
-  std::unique_ptr<DominatorTree> DeleteDT;
-  DominatorTree *DT = nullptr;
-  if (auto *P = getAnalysisIfAvailable<DominatorTreeWrapperPass>())
-    DT = &P->getDomTree();
-
-  if (DT == nullptr && (SInfo.AllocasToInstrument.size() > 1 ||
-                        !F->hasFnAttribute(Attribute::OptimizeNone))) {
-    DeleteDT = std::make_unique<DominatorTree>(*F);
-    DT = DeleteDT.get();
-  }
-
-  std::unique_ptr<PostDominatorTree> DeletePDT;
-  PostDominatorTree *PDT = nullptr;
-  if (auto *P = getAnalysisIfAvailable<PostDominatorTreeWrapperPass>())
-    PDT = &P->getPostDomTree();
-
-  if (PDT == nullptr && !F->hasFnAttribute(Attribute::OptimizeNone)) {
-    DeletePDT = std::make_unique<PostDominatorTree>(*F);
-    PDT = DeletePDT.get();
-  }
+  DominatorTree &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
+  PostDominatorTree &PDT =
+      getAnalysis<PostDominatorTreeWrapperPass>().getPostDomTree();
 
   SetTagFunc =
       Intrinsic::getDeclaration(F->getParent(), Intrinsic::aarch64_settag);
 
-  Instruction *Base = insertBaseTaggedPointer(SInfo.AllocasToInstrument, DT);
+  Instruction *Base = insertBaseTaggedPointer(SInfo.AllocasToInstrument, &DT);
 
   int NextTag = 0;
   for (auto &I : SInfo.AllocasToInstrument) {
@@ -552,7 +539,7 @@
 
     bool StandardLifetime =
         SInfo.UnrecognizedLifetimes.empty() &&
-        memtag::isStandardLifetime(Info.LifetimeStart, Info.LifetimeEnd, DT,
+        memtag::isStandardLifetime(Info.LifetimeStart, Info.LifetimeEnd, &DT,
                                    ClMaxLifetimes);
     // Calls to functions that may return twice (e.g. setjmp) confuse the
     // postdominator analysis, and will leave us to keep memory tagged after
@@ -567,8 +554,7 @@
       tagAlloca(AI, Start->getNextNode(), Start->getArgOperand(1), Size);
 
       auto TagEnd = [&](Instruction *Node) { untagAlloca(AI, Node, Size); };
-      if (!DT || !PDT ||
-          !memtag::forAllReachableExits(*DT, *PDT, Start, Info.LifetimeEnd,
+      if (!memtag::forAllReachableExits(DT, PDT, Start, Info.LifetimeEnd,
                                         SInfo.RetVec, TagEnd)) {
         for (auto *End : Info.LifetimeEnd)
           End->eraseFromParent();
diff --git a/llvm/test/CodeGen/AArch64/stack-tagging.ll b/llvm/test/CodeGen/AArch64/stack-tagging.ll
--- a/llvm/test/CodeGen/AArch64/stack-tagging.ll
+++ b/llvm/test/CodeGen/AArch64/stack-tagging.ll
@@ -102,6 +102,34 @@
 ; CHECK:  ret void
 
 
+define void @ScopeOptnone(i32 %b) sanitize_memtag optnone noinline {
+entry:
+  %x = alloca i32, align 4
+  %tobool = icmp eq i32 %b, 0
+  br i1 %tobool, label %if.end, label %if.then
+
+if.then:
+  %0 = bitcast i32* %x to i8*
+  call void @llvm.lifetime.start.p0i8(i64 4, i8* nonnull %0)
+  call void @use8(i8* %0) #3
+  call void @llvm.lifetime.end.p0i8(i64 4, i8* nonnull %0)
+  br label %if.end
+
+if.end:
+  ret void
+}
+
+; CHECK-LABEL: define void @ScopeOptnone(
+; CHECK:  br i1
+; CHECK:  call void @llvm.lifetime.start.p0i8(
+; CHECK:  call void @llvm.aarch64.settag(
+; CHECK:  call void @use8(
+; CHECK:  call void @llvm.aarch64.settag(
+; CHECK:  call void @llvm.lifetime.end.p0i8(
+; CHECK:  br label
+; CHECK:  ret void
+
+
 ; Spooked by the multiple lifetime ranges, StackTagging remove all of them and sets tags on entry and exit.
 define void @BadScope(i32 %b) sanitize_memtag {
 entry: