Which statement correctly describes the use of the DAG representation for code generation from a Basic Block?

Question

Which statement correctly describes the use of the  DAG representation  for code generation from a Basic Block?

Answer

It can only be used for instruction scheduling, not for optimization.

Answer

It always produces optimal register allocation for the entire function.

Answer

It ensures that the minimum number of temporary variables are used by sharing nodes that represent common subexpressions.

Answer

It is a prerequisite for performing global data flow analysis across the entire control flow graph.

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