diff --git a/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp b/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp
index 079cd11..62c396e 100644
--- a/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp
@@ -658,6 +658,31 @@
       .addUse(Idx);
 }
 
+MachineInstrBuilder
+MachineIRBuilder::buildAtomicCmpXchg(unsigned OldValRes, unsigned Addr,
+                                     unsigned CmpVal, unsigned NewVal,
+                                     MachineMemOperand &MMO) {
+#ifndef NDEBUG
+  LLT OldValResTy = MRI->getType(OldValRes);
+  LLT AddrTy = MRI->getType(Addr);
+  LLT CmpValTy = MRI->getType(CmpVal);
+  LLT NewValTy = MRI->getType(NewVal);
+  assert(OldValResTy.isScalar() && "invalid operand type");
+  assert(AddrTy.isPointer() && "invalid operand type");
+  assert(CmpValTy.isValid() && "invalid operand type");
+  assert(NewValTy.isValid() && "invalid operand type");
+  assert(OldValResTy == CmpValTy && "type mismatch");
+  assert(OldValResTy == NewValTy && "type mismatch");
+#endif
+
+  return buildInstr(TargetOpcode::G_ATOMIC_CMPXCHG)
+      .addDef(OldValRes)
+      .addUse(Addr)
+      .addUse(CmpVal)
+      .addUse(NewVal)
+      .addMemOperand(&MMO);
+}
+
 void MachineIRBuilder::validateTruncExt(unsigned Dst, unsigned Src,
                                         bool IsExtend) {
 #ifndef NDEBUG