diff --git a/mlir/lib/Dialect/Linalg/IR/LinalgOps.cpp b/mlir/lib/Dialect/Linalg/IR/LinalgOps.cpp
--- a/mlir/lib/Dialect/Linalg/IR/LinalgOps.cpp
+++ b/mlir/lib/Dialect/Linalg/IR/LinalgOps.cpp
@@ -1137,7 +1137,8 @@
     // If there are no dimensions in the target to match, then append the
     // `currIndices` to the last element of the reassociationMap.
     if (targetDim == targetShape.size()) {
-      reassociationMap.back().append(currIndices.begin(), currIndices.end());
+      if (!reassociationMap.empty())
+        reassociationMap.back().append(currIndices.begin(), currIndices.end());
       // Break out of the loops. We should be done here.
       break;
     }