Abstract: A system and method for controlling execution of nested loops in parallel in a computer including multiple processors, and a compiler for generating code therefor. The code enables the computer to operate in the following manner. Each processor processes an iteration of an outer loop in a set of nested loops. If the outer loop contains more iterations than processors in the system, the processors are initially assigned early iterations, and the later iterations are assigned to the processors as they finish their earlier iterations, until the processors have processed all of the iterations. Each processor, during processing of an outer loop iteration runs the iterations comprising the inner loop serially. In order to enforce dependencies between the loops, each processor reports its progress in its iterations of the inner loop to the processor executing the succeeding outer loop iteration.

Abstract: A compiler includes a register allocation method making use of the concept of assigning temporary items to lifetime holes if such holes exist that are suitable. The compiler includes a front end for converting the input code to an intermediate representation, then this input representation is traversed to identify all of the temporary items, and to find all of the holes in the temporary items. Lists are maintained of the identified temporaries and holes. Register allocation then includes assigning temporaries to registers so long as there are free registers, and if holes are available in already-assigned temporaries then these holes are used in assigning registers. After all the available registers and holes are used, remaining temporaries are unallocated and thus represent memory references.