Index: llvm/utils/TableGen/CodeGenSchedule.cpp
===================================================================
--- llvm/utils/TableGen/CodeGenSchedule.cpp
+++ llvm/utils/TableGen/CodeGenSchedule.cpp
@@ -734,14 +734,12 @@
 }
 
 bool CodeGenSchedModels::hasReadOfWrite(Record *WriteDef) const {
-  for (const CodeGenSchedRW &Read : SchedReads) {
-    Record *ReadDef = Read.TheDef;
-    if (!ReadDef || !ReadDef->isSubClassOf("ProcReadAdvance"))
-      continue;
-
-    RecVec ValidWrites = ReadDef->getValueAsListOfDefs("ValidWrites");
-    if (is_contained(ValidWrites, WriteDef)) {
-      return true;
+  for (auto& ProcModel : ProcModels) {
+    const RecVec &RADefs = ProcModel.ReadAdvanceDefs;
+    for (auto& RADef : RADefs) {
+      RecVec ValidWrites = RADef->getValueAsListOfDefs("ValidWrites");
+      if (is_contained(ValidWrites, WriteDef))
+        return true;
     }
   }
   return false;