diff --git a/mlir/lib/Dialect/Linalg/Transforms/DropUnitDims.cpp b/mlir/lib/Dialect/Linalg/Transforms/DropUnitDims.cpp
--- a/mlir/lib/Dialect/Linalg/Transforms/DropUnitDims.cpp
+++ b/mlir/lib/Dialect/Linalg/Transforms/DropUnitDims.cpp
@@ -403,12 +403,23 @@
         srcType.getRank() < dstType.getRank() ||
         parentSrcType.getRank() == dstType.getRank())
       return failure();
+
+    // Rank-1 parentSrcType there will always have just an identity
+    // reassociation map.
+    if (parentSrcType.getRank() == 1) {
+      rewriter.replaceOpWithNewOp<TensorReshapeOp>(
+          reshapeOp, dstType, parentReshapeOp.src(),
+          rewriter.getAffineMapArrayAttr({AffineMap::getMultiDimIdentityMap(
+              dstType.getRank(), rewriter.getContext())}));
+      return success();
+    }
+
     // Check if the result tensor_reshape after folding the reshapeOp and
     // parentReshapeOp are combined.
     // If the final tensor_reshape is folding, the parentReshapeOp is
     // introducing unit-dims, and the reshapeOp does an actual reshape.
-    // If the final tensor_reshape op is expanding, the reshapeOp is introducing
-    // unit-dims, and the parentReshapeOp does an actual reshape.
+    // If the final tensor_reshape op is expanding, the reshapeOp is
+    // introducing unit-dims, and the parentReshapeOp does an actual reshape.
     bool isFoldingPattern = parentSrcType.getRank() > dstType.getRank();
     auto reassociationMaps = isFoldingPattern
                                  ? reshapeOp.getReassociationMaps()
diff --git a/mlir/test/Dialect/Linalg/drop-unit-extent-dims.mlir b/mlir/test/Dialect/Linalg/drop-unit-extent-dims.mlir
--- a/mlir/test/Dialect/Linalg/drop-unit-extent-dims.mlir
+++ b/mlir/test/Dialect/Linalg/drop-unit-extent-dims.mlir
@@ -240,3 +240,19 @@
     : tensor<1x4x1x512x1x1x512x1x4xf32> into tensor<4x512x1x512x4xf32>
   return %1 : tensor<4x512x1x512x4xf32>
 }
+
+// -----
+
+//   CHECK-DAG: #[[MAP0:.+]] = affine_map<(d0, d1) -> (d0, d1)>
+//       CHECK: func @fold_reshape
+//       CHECK: linalg.tensor_reshape %{{.*}} [#[[MAP0]]
+//  CHECK-SAME:   tensor<2xf32> into tensor<2x1xf32>
+func @fold_reshape(%arg0: tensor<2xf32>) -> tensor<2x1xf32>
+{
+  %0 = linalg.tensor_reshape %arg0 [affine_map<(d0, d1, d2) -> (d0, d1, d2)>] : tensor<2xf32> into tensor<2x1x1xf32>
+  %1 = linalg.tensor_reshape %0
+  [affine_map<(d0, d1, d2) -> (d0)>,
+   affine_map<(d0, d1, d2) -> (d1, d2)>
+  ] : tensor<2x1x1xf32> into tensor<2x1xf32>
+  return %1 : tensor<2x1xf32>
+}