'early_prop' LIR transformation implements a simple algorithm of constant and copy propagation.
It works only with operands which have single definitions. In addition to constants it also propagates heap reads.
The main goal of the pass is to reduce register pressure.

implementation file: http://svn.apache.org/viewvc/harmony/enhanced/drlvm/trunk/vm/jitrino/src/codegenerator/ia32/Ia32EarlyPropagation.cpp