Slight simplification of addressing math in interpolate.
Slight simplification of addressing math in interpolate.


Former-commit-id: 042984f23f9f58bc2d3e077f76cd02b26209160c
Trass3r/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,darkbuck/Halide,darkbuck/Halide