diff --git a/src/base/SMPInstr.cpp b/src/base/SMPInstr.cpp
index c1cacaec41511c248bf4ca83dd33cf609ffdaaee..b9dca371eaab27ed44a6016518716fab417989f9 100644
--- a/src/base/SMPInstr.cpp
+++ b/src/base/SMPInstr.cpp
@@ -4687,6 +4687,13 @@ bool SMPInstr::MDNormalizeStackOps(bool UseFP, STARS_sval_t FPDelta, bool Recomp
 							this->USEMemOp = NewOp;
 						}
 						else {
+							SMP_msg("\nFATAL ERROR in MDNormalizeStackOps: Stack operand is not the USEMemOp. Inst dump follows.\n");
+							SMP_msg("Stack Op: ");
+							PrintOperand(OldOp);
+							SMP_msg("   USEMemOp: ");
+							PrintOperand(this->USEMemOp);
+							SMP_msg(" \n");
+							this->Dump();
 							assert(false);
 						}
 					}