diff --git a/llvm/include/llvm/InitializePasses.h b/llvm/include/llvm/InitializePasses.h
--- a/llvm/include/llvm/InitializePasses.h
+++ b/llvm/include/llvm/InitializePasses.h
@@ -418,6 +418,7 @@
 void initializeWasmEHPreparePass(PassRegistry&);
 void initializeWinEHPreparePass(PassRegistry&);
 void initializeWriteBitcodePassPass(PassRegistry&);
+void initializeX86DAGToDAGISelPass(PassRegistry &);
 void initializeXRayInstrumentationPass(PassRegistry&);
 
 } // end namespace llvm
diff --git a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
--- a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -26,6 +26,7 @@
 #include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/IntrinsicsX86.h"
 #include "llvm/IR/Type.h"
+#include "llvm/InitializePasses.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/KnownBits.h"
@@ -35,6 +36,7 @@
 using namespace llvm;
 
 #define DEBUG_TYPE "x86-isel"
+#define PASS_NAME "X86 DAG->DAG Instruction Selection"
 
 STATISTIC(NumLoadMoved, "Number of loads moved below TokenFactor");
 
@@ -170,13 +172,12 @@
   public:
     static char ID;
 
-    explicit X86DAGToDAGISel(X86TargetMachine &tm, CodeGenOpt::Level OptLevel)
-        : SelectionDAGISel(ID, tm, OptLevel), Subtarget(nullptr),
+    explicit X86DAGToDAGISel(X86TargetMachine *tm = nullptr,
+                             CodeGenOpt::Level OptLevel = CodeGenOpt::Default)
+        : SelectionDAGISel(ID, *tm, OptLevel), Subtarget(nullptr),
           OptForMinSize(false), IndirectTlsSegRefs(false) {}
 
-    StringRef getPassName() const override {
-      return "X86 DAG->DAG Instruction Selection";
-    }
+    StringRef getPassName() const override { return PASS_NAME; }
 
     bool runOnMachineFunction(MachineFunction &MF) override {
       // Reset the subtarget each time through.
@@ -578,6 +579,8 @@
 
 char X86DAGToDAGISel::ID = 0;
 
+INITIALIZE_PASS(X86DAGToDAGISel, DEBUG_TYPE, PASS_NAME, false, false)
+
 // Returns true if this masked compare can be implemented legally with this
 // type.
 static bool isLegalMaskCompare(SDNode *N, const X86Subtarget *Subtarget) {
@@ -6199,5 +6202,5 @@
 /// ready for instruction scheduling.
 FunctionPass *llvm::createX86ISelDag(X86TargetMachine &TM,
                                      CodeGenOpt::Level OptLevel) {
-  return new X86DAGToDAGISel(TM, OptLevel);
+  return new X86DAGToDAGISel(&TM, OptLevel);
 }
diff --git a/llvm/lib/Target/X86/X86TargetMachine.cpp b/llvm/lib/Target/X86/X86TargetMachine.cpp
--- a/llvm/lib/Target/X86/X86TargetMachine.cpp
+++ b/llvm/lib/Target/X86/X86TargetMachine.cpp
@@ -102,6 +102,7 @@
   initializeX86PartialReductionPass(PR);
   initializePseudoProbeInserterPass(PR);
   initializeX86ReturnThunksPass(PR);
+  initializeX86DAGToDAGISelPass(PR);
 }
 
 static std::unique_ptr<TargetLoweringObjectFile> createTLOF(const Triple &TT) {