diff --git a/llvm/include/llvm/IR/Intrinsics.td b/llvm/include/llvm/IR/Intrinsics.td
index e0ee12391b31d..efecb476c49ee 100644
--- a/llvm/include/llvm/IR/Intrinsics.td
+++ b/llvm/include/llvm/IR/Intrinsics.td
@@ -977,8 +977,12 @@ def int_instrprof_mcdc_tvbitmap_update : Intrinsic<[],
                                         [llvm_ptr_ty, llvm_i64_ty,
                                          llvm_i32_ty, llvm_ptr_ty]>;
 
-def int_call_preallocated_setup : DefaultAttrsIntrinsic<[llvm_token_ty], [llvm_i32_ty]>;
-def int_call_preallocated_arg : DefaultAttrsIntrinsic<[llvm_ptr_ty], [llvm_token_ty, llvm_i32_ty]>;
+def int_call_preallocated_setup
+    : DefaultAttrsIntrinsic<[llvm_token_ty], [llvm_i32_ty],
+                            [ImmArg<ArgIndex<0>>]>;
+def int_call_preallocated_arg
+    : DefaultAttrsIntrinsic<[llvm_ptr_ty], [llvm_token_ty, llvm_i32_ty],
+                            [ImmArg<ArgIndex<1>>]>;
 def int_call_preallocated_teardown : DefaultAttrsIntrinsic<[], [llvm_token_ty]>;
 
 // This intrinsic is intentionally undocumented and users shouldn't call it;
diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index 9fda08645e118..0e1c52a27cfdf 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -5810,9 +5810,7 @@ void Verifier::visitIntrinsicCall(Intrinsic::ID ID, CallBase &Call) {
     break;
   }
   case Intrinsic::call_preallocated_setup: {
-    auto *NumArgs = dyn_cast<ConstantInt>(Call.getArgOperand(0));
-    Check(NumArgs != nullptr,
-          "llvm.call.preallocated.setup argument must be a constant");
+    auto *NumArgs = cast<ConstantInt>(Call.getArgOperand(0));
     bool FoundCall = false;
     for (User *U : Call.users()) {
       auto *UseCall = dyn_cast<CallBase>(U);
@@ -5820,9 +5818,7 @@ void Verifier::visitIntrinsicCall(Intrinsic::ID ID, CallBase &Call) {
             "Uses of llvm.call.preallocated.setup must be calls");
       Intrinsic::ID IID = UseCall->getIntrinsicID();
       if (IID == Intrinsic::call_preallocated_arg) {
-        auto *AllocArgIndex = dyn_cast<ConstantInt>(UseCall->getArgOperand(1));
-        Check(AllocArgIndex != nullptr,
-              "llvm.call.preallocated.alloc arg index must be a constant");
+        auto *AllocArgIndex = cast<ConstantInt>(UseCall->getArgOperand(1));
         auto AllocArgIndexInt = AllocArgIndex->getValue();
         Check(AllocArgIndexInt.sge(0) &&
                   AllocArgIndexInt.slt(NumArgs->getValue()),
diff --git a/llvm/test/Verifier/preallocated-invalid.ll b/llvm/test/Verifier/preallocated-invalid.ll
index 38ed1067c497d..921fa69dcb23b 100644
--- a/llvm/test/Verifier/preallocated-invalid.ll
+++ b/llvm/test/Verifier/preallocated-invalid.ll
@@ -65,7 +65,7 @@ define void @preallocated_one_call() {
     ret void
 }
 
-; CHECK: must be a constant
+; CHECK: immarg operand has non-immediate parameter
 define void @preallocated_setup_constant() {
     %ac = call i32 @blackbox()
     %cs = call token @llvm.call.preallocated.setup(i32 %ac)