DU-chains(Definition-Use) in compiler design
- Consist of a definition of a variable and all its uses, reachable from that definition
- Are created using a form of static code analysis
- Are prerequisite for many compiler optimization including constant propagation and common sub-expression elimination
- All of the above
Answer: D
Explanation:
Use-Definition Chain (UD Chain) is a data structure that consists of a use, U, of a variable, and all the definitions, D, of that variable that can reach that use without any other intervening definitions. A UD Chain generally means the assignment of some value to a variable.
A counterpart of a UD Chain is a Definition-Use Chain (DU Chain), which consists of a definition, D, of a variable and all the uses, U, reachable from that definition without any other intervening definitions.
Both UD and DU chains are created by using a form of static code analysis known as data flow analysis. Knowing the use-def and def-use chains for a program or subprogram is a prerequisite for many compiler optimizations, including constant propagation and common subexpression elimination.
Refer : https://en.wikipedia.org/wiki/Use-define_chain
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