Time Left - 15:00 mins

# GATE CS 2021 : Compiler Design Quiz 7

Attempt now to get your rank among 546 students!

Question 1

Consider the following syntax tree for the expression :

((a+b)-((b+a)*(a-b) ) )+((a-b)*(a+b) )

The letters A through I are used to name the nodes, and are not part of the expression tree. The operator labels of the interior nodes are the +, -, or * adjacent to the nodes. Assume that + and * are commutative operators, although - is not. Construct the expression DAG from this tree, treating + and * as commutative.

Which of the following statements is TRUE(T)/FALSE(F) about which nodes will be combined?

(i) B and C will be combined

(ii) D and H will be combined

(iii) E and C will not be combined

(iv) F and I will not be combined

(v) I and G will not be combined

((a+b)-((b+a)*(a-b) ) )+((a-b)*(a+b) )

The letters A through I are used to name the nodes, and are not part of the expression tree. The operator labels of the interior nodes are the +, -, or * adjacent to the nodes. Assume that + and * are commutative operators, although - is not. Construct the expression DAG from this tree, treating + and * as commutative.

Which of the following statements is TRUE(T)/FALSE(F) about which nodes will be combined?

(i) B and C will be combined

(ii) D and H will be combined

(iii) E and C will not be combined

(iv) F and I will not be combined

(v) I and G will not be combined

Question 2

During intermediate code generation , we use 3 - address code in which we have 3 forms available : Quadruples , Triples and Indirect Triples. Now consider the below statements :

S1 : In Quadruples , statements can be moved around

S2 : In Triples , space is not wasted.

S3 : In Indirect Triples , space is not wasted but access time increases.

Which is correct ?

Question 3

Find the minimum number of temporary variable which is used to represent the following 3 address code in the optimized manner -

T1=a+b

T2=T1+c

T3=T1*T2

T4=2*T3

T5=T4+d

T6=T5+T4

T1=a+b

T2=T1+c

T3=T1*T2

T4=2*T3

T5=T4+d

T6=T5+T4

Question 4

One of the purposes of using intermediate code in compilers is to

Question 5

Which of the following is the machine dependent phase of compiler?

Question 6

What is the equivalent 3-address code for the above DAG?

- 546 attempts
- 4 upvotes
- 5 comments

Oct 16GATE & PSU CS

Posted by: