diff --git a/mlir/include/mlir/Dialect/Affine/IR/AffineOps.h b/mlir/include/mlir/Dialect/Affine/IR/AffineOps.h
--- a/mlir/include/mlir/Dialect/Affine/IR/AffineOps.h
+++ b/mlir/include/mlir/Dialect/Affine/IR/AffineOps.h
@@ -47,7 +47,8 @@
 /// id), transferring chunks of number_of_elements_per_stride every stride until
 /// %num_elements are transferred. Either both or no stride arguments should be
 /// specified. The value of 'num_elements' must be a multiple of
-/// 'number_of_elements_per_stride'.
+/// 'number_of_elements_per_stride'. If the source and destination locations
+/// overlap the behavior of this operation is not defined.
 //
 // For example, an AffineDmaStartOp operation that transfers 256 elements of a
 // memref '%src' in memory space 0 at indices [%i + 3, %j] to memref '%dst' in
diff --git a/mlir/include/mlir/Dialect/MemRef/IR/MemRef.h b/mlir/include/mlir/Dialect/MemRef/IR/MemRef.h
--- a/mlir/include/mlir/Dialect/MemRef/IR/MemRef.h
+++ b/mlir/include/mlir/Dialect/MemRef/IR/MemRef.h
@@ -62,7 +62,9 @@
 // 'index' type, and specify a stride for the slower memory space (memory space
 // with a lower memory space id), transferring chunks of
 // number_of_elements_per_stride every stride until %num_elements are
-// transferred. Either both or no stride arguments should be specified.
+// transferred. Either both or no stride arguments should be specified. If the
+// source and destination locations overlap the behavior of this operation is
+// not defined.
 //
 // For example, a DmaStartOp operation that transfers 256 elements of a memref
 // '%src' in memory space 0 at indices [%i, %j] to memref '%dst' in memory space
diff --git a/mlir/lib/Dialect/Affine/IR/AffineOps.cpp b/mlir/lib/Dialect/Affine/IR/AffineOps.cpp
--- a/mlir/lib/Dialect/Affine/IR/AffineOps.cpp
+++ b/mlir/lib/Dialect/Affine/IR/AffineOps.cpp
@@ -1078,10 +1078,6 @@
   if (!getOperand(getTagMemRefOperandIndex()).getType().isa<MemRefType>())
     return emitOpError("expected DMA tag to be of memref type");
 
-  // DMAs from different memory spaces supported.
-  if (getSrcMemorySpace() == getDstMemorySpace()) {
-    return emitOpError("DMA should be between different memory spaces");
-  }
   unsigned numInputsAllMaps = getSrcMap().getNumInputs() +
                               getDstMap().getNumInputs() +
                               getTagMap().getNumInputs();
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
@@ -943,10 +943,6 @@
                     [](Type t) { return t.isIndex(); }))
     return emitOpError("expected tag indices to be of index type");
 
-  // DMAs from different memory spaces supported.
-  if (getSrcMemorySpace() == getDstMemorySpace())
-    return emitOpError("DMA should be between different memory spaces");
-
   // Optional stride-related operands must be either both present or both
   // absent.
   if (numOperands != numExpectedOperands &&
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
@@ -388,15 +388,6 @@
 
 // -----
 
-func @dma_start_same_space(
-    %src: memref<2x2xf32>, %idx: index, %dst: memref<2xf32>,
-    %tag: memref<i32,2>) {
-  // expected-error@+1 {{DMA should be between different memory spaces}}
-  memref.dma_start %src[%idx, %idx], %dst[%idx], %idx, %tag[] : memref<2x2xf32>, memref<2xf32>, memref<i32,2>
-}
-
-// -----
-
 func @dma_start_too_many_operands(
     %src: memref<2x2xf32>, %idx: index, %dst: memref<2xf32,1>,
     %tag: memref<i32,2>) {