A Comment on Index Register Allocation
A technique is presented to reduce the enumeration
required by a known procedure for optimal 
index register allocation in straight-line programs.
 This technique is based on the construction of 
a link diagram, which shows at any step the future occurrences
of indexes which must be loaded into index 
registers.  This diagram determines in advance the required
register configuration at certain steps of 
the program, so that the program is subdivided into separate
portions to which the allocation procedure 
may be applied independently.
CACM September, 1967
Luccio, F.
