diff --git a/mlir/lib/Analysis/Presburger/Simplex.cpp b/mlir/lib/Analysis/Presburger/Simplex.cpp
--- a/mlir/lib/Analysis/Presburger/Simplex.cpp
+++ b/mlir/lib/Analysis/Presburger/Simplex.cpp
@@ -66,6 +66,7 @@
     tableau.resizeVertically(nRow);
   rowUnknown.push_back(~con.size());
   con.emplace_back(Orientation::Row, makeRestricted, nRow - 1);
+  undoLog.push_back(UndoLogEntry::RemoveLastConstraint);
 
   // Zero out the new row.
   tableau.fillRow(nRow - 1, 0);
@@ -131,7 +132,6 @@
 
   normalizeRow(nRow - 1);
   // Push to undo log along with the index of the new constraint.
-  undoLog.push_back(UndoLogEntry::RemoveLastConstraint);
   return con.size() - 1;
 }