Detect when there is only single prefetch op needed on higher dimension boxes
Detect when there is only single prefetch op needed on higher dimension boxes


Former-commit-id: 2ae6c7c24de51fe5e0832f0845ca82cb7815cbc6
Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide