diff --git a/lib/SIL/IR/OperandOwnership.cpp b/lib/SIL/IR/OperandOwnership.cpp
index fade6f9b17c..99d70ff4244 100644
--- a/lib/SIL/IR/OperandOwnership.cpp
+++ b/lib/SIL/IR/OperandOwnership.cpp
@@ -821,7 +821,14 @@ BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, PoundAssert)
 BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, GlobalStringTablePointer)
 BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, TypePtrAuthDiscriminator)
 BUILTIN_OPERAND_OWNERSHIP(InstantaneousUse, TargetOSVersionAtLeast)
-BUILTIN_OPERAND_OWNERSHIP(UnownedInstantaneousUse, Copy)
+OperandOwnership OperandOwnershipBuiltinClassifier::visitCopy(BuiltinInst *bi,
+                                                              StringRef) {
+  if (bi->getFunction()->getConventions().useLoweredAddresses()) {
+    return OperandOwnership::UnownedInstantaneousUse;
+  } else {
+    return OperandOwnership::DestroyingConsume;
+  }
+}
 BUILTIN_OPERAND_OWNERSHIP(DestroyingConsume, StartAsyncLet)
 BUILTIN_OPERAND_OWNERSHIP(DestroyingConsume, EndAsyncLet)
 BUILTIN_OPERAND_OWNERSHIP(DestroyingConsume, StartAsyncLetWithLocalBuffer)
diff --git a/lib/SILOptimizer/Mandatory/AddressLowering.cpp b/lib/SILOptimizer/Mandatory/AddressLowering.cpp
index 774266ffc91..ba7a52a835e 100644
--- a/lib/SILOptimizer/Mandatory/AddressLowering.cpp
+++ b/lib/SILOptimizer/Mandatory/AddressLowering.cpp
@@ -2617,6 +2617,19 @@ protected:
     vmi->setOperand(opAddr);
   }
 
+  void visitBuiltinInst(BuiltinInst *bi) {
+    switch (bi->getBuiltinKind().getValueOr(BuiltinValueKind::None)) {
+    case BuiltinValueKind::Copy: {
+      SILValue opAddr = addrMat.materializeAddress(use->get());
+      bi->setOperand(0, opAddr);
+      break;
+    }
+    default:
+      bi->dump();
+      llvm::report_fatal_error("^^^ Unimplemented builtin opaque value use.");
+    }
+  }
+
   void visitBeginBorrowInst(BeginBorrowInst *borrow);
 
   void visitEndBorrowInst(EndBorrowInst *end) {}
@@ -3112,6 +3125,22 @@ protected:
     ApplyRewriter(bai, pass).convertBeginApplyWithOpaqueYield();
   }
 
+  void visitBuiltinInst(BuiltinInst *bi) {
+    switch (bi->getBuiltinKind().getValueOr(BuiltinValueKind::None)) {
+    case BuiltinValueKind::Copy: {
+      SILValue addr = addrMat.materializeAddress(bi);
+      builder.createBuiltin(
+          bi->getLoc(), bi->getName(),
+          SILType::getEmptyTupleType(bi->getType().getASTContext()),
+          bi->getSubstitutions(), {addr, bi->getOperand(0)});
+      break;
+    }
+    default:
+      bi->dump();
+      llvm::report_fatal_error("^^^ Unimplemented builtin opaque value def.");
+    }
+  }
+
   // Rewrite the apply for an indirect result.
   void visitDestructureTupleInst(DestructureTupleInst *destructure) {
     SILValue srcVal = destructure->getOperand();
diff --git a/test/SILOptimizer/opaque_values_Onone_stdlib.swift b/test/SILOptimizer/opaque_values_Onone_stdlib.swift
new file mode 100644
index 00000000000..19c4ab8bc0e
--- /dev/null
+++ b/test/SILOptimizer/opaque_values_Onone_stdlib.swift
@@ -0,0 +1,34 @@
+// RUN: %target-swift-frontend -parse-stdlib -enable-experimental-move-only -module-name main -enable-sil-opaque-values -parse-as-library -emit-sil -Onone %s | %FileCheck %s
+
+// Like opaque_values_Onone.swift but for code that needs to be compiled with 
+// -parse-stdlib.
+
+class X {}
+
+func consume(_ x : __owned X) {}
+
+func foo(@_noImplicitCopy _ x: __owned X) {
+  consume(_copy(x))
+  consume(x)
+}
+
+// CHECK-LABEL: sil [transparent] [_semantics "lifetimemanagement.copy"] @_copy : {{.*}} {
+// CHECK:       {{bb[0-9]+}}([[OUT_ADDR:%[^,]+]] : $*T, [[IN_ADDR:%[^,]+]] : $*T):
+// CHECK:         [[TMP_ADDR:%[^,]+]] = alloc_stack $T
+// CHECK:         copy_addr [[IN_ADDR]] to [init] [[TMP_ADDR]] : $*T
+// CHECK:         [[REGISTER_5:%[^,]+]] = builtin "copy"<T>([[OUT_ADDR]] : $*T, [[TMP_ADDR]] : $*T) : $()
+// CHECK:         dealloc_stack [[TMP_ADDR]] : $*T
+// CHECK:         return {{%[^,]+}} : $()
+// CHECK-LABEL: } // end sil function '_copy'
+@_transparent
+@_semantics("lifetimemanagement.copy")
+@_silgen_name("_copy")
+public func _copy<T>(_ value: T) -> T {
+  #if $BuiltinCopy
+    Builtin.copy(value)
+  #else
+    value
+  #endif
+}
+
+