'ssa' - convert HIR into single static assignment(SSA) form/
The pass converts Control Flow Graph into single static assignment (SSA) form where each operand has exactly one assignment.
The SSA form provides explicit use-def links between operands and their defining instructions, which simplifies and speeds up high-level optimizations.
header file: http://svn.apache.org/viewvc/harmony/enhanced/drlvm/trunk/vm/jitrino/src/optimizer/ssa/SSA.h
implementation file: http://svn.apache.org/viewvc/harmony/enhanced/drlvm/trunk/vm/jitrino/src/optimizer/ssa/SSA.cpp