Before revision:  First solutions to this problem have been proposed, such as TVM  or ISAMIR, which work on a loop-level representation of operators and rewrite the program before an instruction embedding into the operator is performed .
After revision:  First solutions to this problem have been proposed, such as TVM or ISAMIR, which work on a loop-level representation of operators and specify data layout and possible program transformations before the embedding into the operator is performed .