diff --git a/mlir/lib/IR/AsmPrinter.cpp b/mlir/lib/IR/AsmPrinter.cpp
--- a/mlir/lib/IR/AsmPrinter.cpp
+++ b/mlir/lib/IR/AsmPrinter.cpp
@@ -1650,6 +1650,9 @@
       .Case<UnrankedMemRefType>([&](UnrankedMemRefType memrefTy) {
         os << "memref<*x";
         printType(memrefTy.getElementType());
+        // Only print the memory space if it is the non-default one.
+        if (memrefTy.getMemorySpace())
+          os << ", " << memrefTy.getMemorySpace();
         os << '>';
       })
       .Case<ComplexType>([&](ComplexType complexTy) {
diff --git a/mlir/test/IR/core-ops.mlir b/mlir/test/IR/core-ops.mlir
--- a/mlir/test/IR/core-ops.mlir
+++ b/mlir/test/IR/core-ops.mlir
@@ -703,6 +703,11 @@
   return
 }
 
+// Check that unranked memrefs with non-default memory space roundtrip
+// properly.
+// CHECK-LABEL: @unranked_memref_roundtrip(memref<*xf32, 4>)
+func @unranked_memref_roundtrip(memref<*xf32, 4>)
+
 // CHECK-LABEL: func @memref_view(%arg0
 func @memref_view(%arg0 : index, %arg1 : index, %arg2 : index) {
   %0 = alloc() : memref<2048xi8>
diff --git a/mlir/test/IR/invalid-ops.mlir b/mlir/test/IR/invalid-ops.mlir
--- a/mlir/test/IR/invalid-ops.mlir
+++ b/mlir/test/IR/invalid-ops.mlir
@@ -1076,7 +1076,7 @@
 // incompatible memory space
 func @invalid_memref_cast() {
   %0 = alloc() : memref<2x5xf32, 0>
-  // expected-error@+1 {{operand type 'memref<2x5xf32>' and result type 'memref<*xf32>' are cast incompatible}}
+  // expected-error@+1 {{operand type 'memref<2x5xf32>' and result type 'memref<*xf32, 1>' are cast incompatible}}
   %1 = memref_cast %0 : memref<2x5xf32, 0> to memref<*xf32, 1>
   return
 }