diff --git a/llvm/test/TableGen/CompressWriteLatencyEntry.td b/llvm/test/TableGen/CompressWriteLatencyEntry.td
new file mode 100644
--- /dev/null
+++ b/llvm/test/TableGen/CompressWriteLatencyEntry.td
@@ -0,0 +1,54 @@
+// RUN: llvm-tblgen -gen-subtarget -I %p/../../include %s 2>&1 | FileCheck %s
+
+// Make sure that ReadAdvance entries are correctly processed.
+// Not all ProcReadAdvance definitions implicitly inherit from SchedRead.
+// Some ProcReadAdvances are subclasses of ReadAdvance.
+
+include "llvm/Target/Target.td"
+
+def MyTarget : Target;
+
+let OutOperandList = (outs), InOperandList = (ins) in {
+  def Inst_A : Instruction;
+  def Inst_B : Instruction;
+  def Inst_C : Instruction;
+
+}
+
+let CompleteModel = 0 in {
+  def SchedModel_A: SchedMachineModel;
+}
+
+def Read_D : SchedRead;
+
+// CHECK: extern const llvm::MCWriteLatencyEntry MyTargetWriteLatencyTable[] = {
+// CHECK-NEXT:  { 0,  0}, // Invalid
+// CHECK-NEXT:  { 1,  0}, // #1 Write_A_Write_C
+// CHECK-NEXT:  { 1,  2} // #2 Write_B
+// CHECK-NEXT: }; // MyTargetWriteLatencyTable
+
+// CHECK: extern const llvm::MCReadAdvanceEntry MyTargetReadAdvanceTable[] = {
+// CHECK-NEXT:  {0,  0,  0}, // Invalid
+// CHECK-NEXT:  {0,  2,  1} // #1
+// CHECK-NEXT: }; // MyTargetReadAdvanceTable
+
+// CHECK:  static const llvm::MCSchedClassDesc SchedModel_ASchedClasses[] = {
+// CHECK-NEXT:  {DBGFIELD("InvalidSchedClass")  8191, false, false, false, 0, 0,  0, 0,  0, 0},
+// CHECK-NEXT:  {DBGFIELD("Inst_A")             1, false, false, false,  0, 0,  1, 1,  0, 0}, // #1
+// CHECK-NEXT:  {DBGFIELD("Inst_B")             1, false, false, false,  0, 0,  2, 1,  0, 0}, // #2
+// CHECK-NEXT:  {DBGFIELD("Inst_C")             1, false, false, false,  0, 0,  1, 1,  1, 1}, // #3
+// CHECK-NEXT: }; // SchedModel_ASchedClasses
+
+let SchedModel = SchedModel_A in {
+  def Write_A : SchedWriteRes<[]>;
+  def Write_B : SchedWriteRes<[]>;
+  def Write_C : SchedWriteRes<[]>;
+
+  def : InstRW<[Write_A], (instrs Inst_A)>;
+  def : InstRW<[Write_B], (instrs Inst_B)>;
+  def : InstRW<[Write_C, Read_D], (instrs Inst_C)>;
+
+  def : ReadAdvance<Read_D, 1, [Write_B]>;
+}
+
+def ProcessorA: ProcessorModel<"ProcessorA", SchedModel_A, []>;
diff --git a/llvm/utils/TableGen/CodeGenSchedule.cpp b/llvm/utils/TableGen/CodeGenSchedule.cpp
--- a/llvm/utils/TableGen/CodeGenSchedule.cpp
+++ b/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;