Index: lib/CodeGen/DwarfEHPrepare.cpp
===================================================================
--- lib/CodeGen/DwarfEHPrepare.cpp
+++ lib/CodeGen/DwarfEHPrepare.cpp
@@ -80,7 +80,6 @@
 char DwarfEHPrepare::ID = 0;
 INITIALIZE_TM_PASS_BEGIN(DwarfEHPrepare, "dwarfehprepare",
                          "Prepare DWARF exceptions", false, false)
-INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
 INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)
 INITIALIZE_TM_PASS_END(DwarfEHPrepare, "dwarfehprepare",
                        "Prepare DWARF exceptions", false, false)
@@ -91,7 +90,7 @@
 
 void DwarfEHPrepare::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.addRequired<TargetTransformInfoWrapperPass>();
-  AU.addRequired<DominatorTreeWrapperPass>();
+  AU.addUsedIfAvailable<DominatorTreeWrapperPass>();
 }
 
 /// GetExceptionObject - Return the exception object from the value passed into
@@ -255,7 +254,10 @@
 
 bool DwarfEHPrepare::runOnFunction(Function &Fn) {
   assert(TM && "DWARF EH preparation requires a target machine");
-  DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
+  if (auto *DTWP = getAnalysisIfAvailable<DominatorTreeWrapperPass>())
+    DT = &DTWP->getDomTree();
+  else
+    DT = nullptr;
   TLI = TM->getSubtargetImpl(Fn)->getTargetLowering();
   bool Changed = InsertUnwindResumeCalls(Fn);
   DT = nullptr;
Index: lib/CodeGen/TargetPassConfig.cpp
===================================================================
--- lib/CodeGen/TargetPassConfig.cpp
+++ lib/CodeGen/TargetPassConfig.cpp
@@ -24,6 +24,7 @@
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/CodeGen/RegAllocRegistry.h"
 #include "llvm/CodeGen/RegisterUsageInfo.h"
+#include "llvm/IR/Dominators.h"
 #include "llvm/IR/IRPrintingPasses.h"
 #include "llvm/IR/LegacyPassManager.h"
 #include "llvm/IR/Verifier.h"
@@ -502,6 +503,8 @@
     LLVM_FALLTHROUGH;
   case ExceptionHandling::DwarfCFI:
   case ExceptionHandling::ARM:
+    if (getOptLevel() != CodeGenOpt::None)
+      addPass(&DominatorTreeWrapperPass::ID);
     addPass(createDwarfEHPass(TM));
     break;
   case ExceptionHandling::WinEH:
@@ -509,6 +512,8 @@
     // add both preparation passes. Each pass will only actually run if it
     // recognizes the personality function.
     addPass(createWinEHPass(TM));
+    if (getOptLevel() != CodeGenOpt::None)
+      addPass(&DominatorTreeWrapperPass::ID);
     addPass(createDwarfEHPass(TM));
     break;
   case ExceptionHandling::None:
Index: test/CodeGen/X86/O0-pipeline.ll
===================================================================
--- test/CodeGen/X86/O0-pipeline.ll
+++ test/CodeGen/X86/O0-pipeline.ll
@@ -25,7 +25,6 @@
 ; CHECK-NEXT:       Inserts calls to mcount-like functions
 ; CHECK-NEXT:     Rewrite Symbols
 ; CHECK-NEXT:     FunctionPass Manager
-; CHECK-NEXT:       Dominator Tree Construction
 ; CHECK-NEXT:       Exception handling preparation
 ; CHECK-NEXT:       Safe Stack instrumentation pass
 ; CHECK-NEXT:       Insert stack protectors