Question

DAG representation of a basic block allows __________

(a) Automatic detection of local common sub expressions

(b) Detection of induction variables

(c) Automatic detection of loop variant

(d) None of the mentioned

I had been asked this question in an international level competition.

My question is taken from Handle of Right sentinel Grammar in chapter Bottom Up Parsing of Compiler

Answer 1

The correct option is (a) Automatic detection of local common sub expressions

For explanation I would say: It detects local sub expression.