1. In a compilation environment, a method executed by a computing device comprising: detecting a series of loop nests corresponding to source code; processing a higher-level internal representation comprising a data structure corresponding to the source code, the processing including: splitting the data structure containing array nodes of a graph into sub-graphs containing break nodes and non-break array nodes, the break nodes obtained by placing break marks at one or more of the array nodes and where the break nodes are roots of the sub-graphs, completely instantiating the break nodes before their parent nodes are processed, and, for the non-break array nodes, instantiating only elements required for a current iteration space tile; and tiling the series of loop nests together.