diff --git a/runtime/vm/compiler/backend/il_arm64.cc b/runtime/vm/compiler/backend/il_arm64.cc
index 9cc43f7..112d9bf 100644
--- a/runtime/vm/compiler/backend/il_arm64.cc
+++ b/runtime/vm/compiler/backend/il_arm64.cc
@@ -1582,7 +1582,8 @@
 
 LocationSummary* CCallInstr::MakeLocationSummary(Zone* zone,
                                                  bool is_optimizing) const {
-  constexpr Register saved_csp = kAbiFirstPreservedCpuReg;
+  // Compare FfiCallInstr's use of kFfiAnyNonAbiRegister.
+  constexpr Register saved_csp = CallingConventions::kFfiAnyNonAbiRegister;
   ASSERT(IsAbiPreservedRegister(saved_csp));
   return MakeLocationSummaryInternal(zone, (R(saved_csp)));
 }