The least number of temporary variables required to create a three-address code in static single assignment form for the expression p+q*r-s/(q*r)Correct answer is '5'. Can you explain this answer?

Question

Answer

Expression: p q*r-s/(q*r)

Three-address code: Three-address code is a type of intermediate code representation that breaks down an expression into a sequence of instructions, each containing at most three operands. In static single assignment (SSA) form, each variable is assigned only once.

To create a three-address code in SSA form for the given expression, we need to break it down into smaller sub-expressions and assign temporary variables to hold the intermediate results.

Sub-expressions:
1. q * r
2. s / (q * r)
3. p - (s / (q * r))

Temporary variables:
To create the three-address code, we will need temporary variables to hold the intermediate results of the sub-expressions. Let's assign temporary variables t1, t2, t3, t4, and t5.

Step-by-step breakdown:

1. Evaluate the sub-expression q * r and assign it to temporary variable t1.
- Three-address code: t1 = q * r

2. Evaluate the sub-expression s / (q * r) and assign it to temporary variable t2.
- Three-address code: t2 = s / t1

3. Evaluate the sub-expression p - (s / (q * r)) and assign it to temporary variable t3.
- Three-address code: t3 = p - t2

4. Evaluate the sub-expression q * r and assign it to temporary variable t4.
- Three-address code: t4 = q * r

5. Evaluate the sub-expression t3 / t4 and assign it to temporary variable t5.
- Three-address code: t5 = t3 / t4

Final three-address code:
1. t1 = q * r
2. t2 = s / t1
3. t3 = p - t2
4. t4 = q * r
5. t5 = t3 / t4

Number of temporary variables:
We have used 5 temporary variables (t1, t2, t3, t4, t5) to create the three-address code in SSA form for the given expression.

Answer

T1 and t3 both represent the same expression , so why we need two variable for this ? Can you please explain ?

Similar Computer Science Engineering (CSE) Doubts

Consider the following code segment.x = u - t;y = x * v;x = y + w;y = t - z;y = x * y;The minimum number of total variables required to convert the above code segment to static single assignment form is __________. Correct answer is '10'. Can you explain this answer?

Consider the following C function:int foo(){int i;int sum = 0;for(i = 1; i < = 20; i++) sum = sum + i;return sum;}Calculate the least number of temporary variables required to create an intermediate code for above C function. Correct answer is '2'. Can you explain this answer?

Consider the statementdo{i = i + 1;}While(a[i] < b);The minimum number of variables required in three address code of the above statement is _____. Correct answer is '3'. Can you explain this answer?

Consider the following 3-address code. 1₁ = t + e t_{2}=g+a 3=42 t_{4}=b+t_{2} 16=4+ There are five temporary variables in above code. Find minimum number of temporary variables can be used in the equivalent optimized 3-address code of above code.?

The minimum number of temporary variables needed to swap the contents of two variables is

Top Courses for Computer Science Engineering (CSE)View all

GATE Computer Science Engineering(CSE) 2025 Mock Test Series

Question Bank for GATE Computer Science Engineering

General Aptitude for GATE

Computer Networks

Programming and Data Structures

Top Courses for Computer Science Engineering (CSE)

Top Courses for Computer Science Engineering (CSE)

Suggested Free Tests

Related Content

Mock Test Series

Subject-wise Courses

Subject-wise Courses

Other Engg Branches

Company