1 files changed, 6 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/MachineFunction.cpp b/llvm/lib/CodeGen/MachineFunction.cpp
index 4a838b8..d8f786e 100644
--- a/llvm/lib/CodeGen/MachineFunction.cpp
+++ b/llvm/lib/CodeGen/MachineFunction.cpp
@@ -974,6 +974,9 @@ void MachineFunction::makeDebugValueSubstitution(DebugInstrOperandPair A,
                                                  unsigned Subreg) {
   // Catch any accidental self-loops.
   assert(A.first != B.first);
+  // Don't allow any substitutions _from_ the memory operand number.
+  assert(A.second != DebugOperandMemNumber);
+
   DebugValueSubstitutions.push_back({A, B, Subreg});
 }
 
@@ -1239,6 +1242,9 @@ bool MachineFunction::useDebugInstrRef() const {
   return false;
 }
 
+// Use one million as a high / reserved number.
+const unsigned MachineFunction::DebugOperandMemNumber = 1000000;
+
 /// \}
 
 //===----------------------------------------------------------------------===//