diff --git a/mlir/lib/Dialect/MemRef/IR/MemRefOps.cpp b/mlir/lib/Dialect/MemRef/IR/MemRefOps.cpp
--- a/mlir/lib/Dialect/MemRef/IR/MemRefOps.cpp
+++ b/mlir/lib/Dialect/MemRef/IR/MemRefOps.cpp
@@ -632,6 +632,12 @@
       }
       resultIndex++;
     }
+    // If the source index is greater that the number of static sizes specified,
+    // then the semantics of the `SubViewOp` is that the size is same as the
+    // size of the the source. Do nothing here, and rely on subview op folder to
+    // fold away the subview itself.
+    if (sourceIndex >= subview.static_sizes().size())
+      return {};
     assert(subview.isDynamicSize(sourceIndex) &&
            "expected dynamic subview size");
     return subview.getDynamicSize(sourceIndex);
@@ -1913,6 +1919,29 @@
     return success();
   }
 };
+
+/// Fold `memref.subview` with empty offsets, sizes and strides to the `source`
+/// (with casts to address type consistency).
+class TrivialSubViewOpFolder final : public OpRewritePattern<SubViewOp> {
+public:
+  using OpRewritePattern<SubViewOp>::OpRewritePattern;
+
+  LogicalResult matchAndRewrite(SubViewOp subViewOp,
+                                PatternRewriter &rewriter) const override {
+    if (!subViewOp.static_offsets().empty() ||
+        !subViewOp.static_sizes().empty() ||
+        !subViewOp.static_strides().empty())
+      return failure();
+    Value source = subViewOp.source();
+    if (subViewOp.getSourceType() == subViewOp.getType()) {
+      rewriter.replaceOp(subViewOp, source);
+      return success();
+    }
+    rewriter.replaceOpWithNewOp<CastOp>(subViewOp, subViewOp.getType(), source);
+    return success();
+  }
+};
+
 } // namespace
 
 /// Return the canonical type of the result of a subview.
@@ -1938,7 +1967,7 @@
   results
       .add<OpWithOffsetSizesAndStridesConstantArgumentFolder<
                SubViewOp, SubViewReturnTypeCanonicalizer, SubViewCanonicalizer>,
-           SubViewOpMemRefCastFolder>(context);
+           SubViewOpMemRefCastFolder, TrivialSubViewOpFolder>(context);
 }
 
 OpFoldResult SubViewOp::fold(ArrayRef<Attribute> operands) {
@@ -1949,6 +1978,10 @@
       resultShapedType == sourceShapedType) {
     return getViewSource();
   }
+  // If the offsets, sizes and strides are empty, the subview is a no-op.
+  if (static_offsets().empty() && static_sizes().empty() &&
+      static_strides().empty())
+    return getViewSource();
 
   return {};
 }
diff --git a/mlir/test/Dialect/MemRef/canonicalize.mlir b/mlir/test/Dialect/MemRef/canonicalize.mlir
--- a/mlir/test/Dialect/MemRef/canonicalize.mlir
+++ b/mlir/test/Dialect/MemRef/canonicalize.mlir
@@ -417,3 +417,14 @@
 //       CHECK:   %[[RESULT:.+]] = memref.subview
 //  CHECK-SAME:       memref<2x5x7x1xf32> to memref<1x4x1xf32, #{{.+}}>
 //       CHECK:   return %[[RESULT]]
+
+// -----
+
+func @no_op_scalar_subview(%arg0 : memref<f32>) -> memref<f32, affine_map<() -> (0)>> {
+  %0 = memref.subview %arg0[] [] [] : memref<f32> to memref<f32, affine_map<() -> (0)>>
+  return %0 : memref<f32, affine_map<() -> (0)>>
+}
+//      CHECK: func @no_op_scalar_subview(
+// CHECK-SAME:     %[[ARG0:.+]]: memref<f32>
+//      CHECK:   %[[CAST:.+]] = memref.cast %[[ARG0]]
+//      CHECK:   return %[[CAST]]
diff --git a/mlir/test/Dialect/MemRef/fold-subview-ops.mlir b/mlir/test/Dialect/MemRef/fold-subview-ops.mlir
--- a/mlir/test/Dialect/MemRef/fold-subview-ops.mlir
+++ b/mlir/test/Dialect/MemRef/fold-subview-ops.mlir
@@ -251,3 +251,18 @@
 //   CHECK-DAG:    %[[IDX1:.+]] = affine.apply #[[MAP1]](%[[ARG7]])[%[[ARG3]]]
 //   CHECK-DAG:    vector.transfer_write %[[ARG1]], %[[ARG0]][%[[IDX0]], %[[IDX1]], %[[C0]]]
 //  CHECK-SAME:    {in_bounds = [true], permutation_map = #[[MAP2]]} : vector<4xf32>, memref<?x?x?xf32
+
+// -----
+
+#map = affine_map<(d0, d1)[s0, s1] -> (d0 * s1 + s0 + d1)>
+func @no_op_subview(%arg0 : memref<?x?xf32, #map>) -> index {
+  %c1 = arith.constant 1 : index
+  %0 = memref.subview %arg0[] [] [] : memref<?x?xf32, #map> to memref<?x?xf32, #map>
+  %1 = memref.dim %0, %c1 : memref<?x?xf32, #map>
+  return %1 : index
+}
+//      CHECK: func @no_op_subview(
+// CHECK-SAME:     %[[ARG0:.+]]: memref<?x?xf32
+//      CHECK:   %[[C1:.+]] = arith.constant 1 : index
+//      CHECK:   %[[RETURN:.+]] = memref.dim %[[ARG0]], %[[C1]]
+//      CHECK:   return %[[RETURN]]