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
@@ -1298,7 +1298,8 @@
 /// copies.
 static bool isReshapableDimBand(unsigned dim, unsigned extent,
                                 ArrayRef<int64_t> sizes,
-                                ArrayRef<AffineExpr> strides) {
+                                ArrayRef<AffineExpr> strides,
+                                bool isIdentityLayout) {
   // Bands of extent one can be reshaped, as they are not reshaped at all.
   if (extent == 1)
     return true;
@@ -1316,8 +1317,10 @@
     if (ShapedType::isDynamic(sizes[idx + 1]))
       return false;
     // TODO: Refine this by passing the proper nDims and nSymbols so we can
-    // simplify on the fly and catch more reshapable cases.
-    if (strides[idx] != strides[idx + 1] * sizes[idx + 1])
+    // simplify on the fly and catch more reshapable cases. For now, if we
+    // know it is an identity layout, ignore strides to support dynamic cases.
+    if (!isIdentityLayout &&
+        (strides[idx] != strides[idx + 1] * sizes[idx + 1]))
       return false;
   }
   return true;
@@ -1334,6 +1337,7 @@
   AffineExpr offset;
   SmallVector<AffineExpr, 4> strides;
   auto status = getStridesAndOffset(type, strides, offset);
+  auto isIdentityLayout = type.getLayout().isIdentity();
   (void)status;
   assert(succeeded(status) && "expected strided memref");
 
@@ -1350,7 +1354,8 @@
     unsigned dim = m.getNumResults();
     int64_t size = 1;
     AffineExpr stride = strides[currentDim + dim - 1];
-    if (!isReshapableDimBand(currentDim, dim, sizes, strides)) {
+    if (!isReshapableDimBand(currentDim, dim, sizes, strides,
+                             isIdentityLayout)) {
       size = ShapedType::kDynamicSize;
       stride = AffineExpr();
     } else {
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
@@ -406,6 +406,8 @@
   return %collapsed : memref<?x?xf32>
 }
 
+// -----
+
 // CHECK-LABEL:   func @collapse_after_memref_cast(
 // CHECK-SAME:      %[[INPUT:.*]]: memref<?x512x1x?xf32>) -> memref<?x?xf32> {
 // CHECK:           %[[COLLAPSED:.*]] = memref.collapse_shape %[[INPUT]]
@@ -419,6 +421,21 @@
 
 // -----
 
+// CHECK-LABEL:   func @collapse_after_memref_cast_type_change_dynamic(
+// CHECK-SAME:      %[[INPUT:.*]]: memref<1x1x1x?xi64>) -> memref<?x?xi64> {
+// CHECK:           %[[COLLAPSED:.*]] = memref.collapse_shape %[[INPUT]]
+// CHECK_SAME:        {{\[\[}}0, 1, 2], [3]] : memref<1x1x1x?xi64> into memref<1x?xi64>
+// CHECK:           %[[DYNAMIC:.*]] = memref.cast %[[COLLAPSED]] :
+// CHECK-SAME:         memref<1x?xi64> to memref<?x?xi64>
+// CHECK:           return %[[DYNAMIC]] : memref<?x?xi64>
+func @collapse_after_memref_cast_type_change_dynamic(%arg0: memref<1x1x1x?xi64>) -> memref<?x?xi64> {
+  %casted = memref.cast %arg0 : memref<1x1x1x?xi64> to memref<1x1x?x?xi64>
+  %collapsed = memref.collapse_shape %casted [[0, 1, 2], [3]] : memref<1x1x?x?xi64> into memref<?x?xi64>
+  return %collapsed : memref<?x?xi64>
+}
+
+// -----
+
 func @reduced_memref(%arg0: memref<2x5x7x1xf32>, %arg1 :index)
     -> memref<1x4x1xf32, affine_map<(d0, d1, d2)[s0] -> (d0 * 35 + s0 + d1 * 7 + d2)>> {
   %c0 = arith.constant 0 : index