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Strength Reduction

*Strength Reduction* (SR) [2] replaces expensive
operations by equivalent cheaper ones from the target machine
language. Some machine instructions are considerably cheaper than
others and can often be used as special cases of more expensive
operators. For instance, is invariably cheaper to implement as
than as a call to an exponentiation routine. Moreover, an
additive operator is generally cheaper than a multiplicative operator.
SR is a very powerful algorithm to
transform computations involving multiplications and additions
together into computations only using additions. It is a natural
candidate to optimize the current HPJava compiler
because of the complexity of the terms in the subscript
expression of a multiarray element access.

Bryan Carpenter
2004-04-24