1. What is the primary goal of instruction selection in a compiler?
A) To optimize the performance of the target program
B) To generate machine-specific instructions from intermediate code
C) To detect syntax errors in the source code
D) To allocate registers efficiently
Answer: B) To generate machine-specific instructions from intermediate code
2. Which of the following describes instruction scheduling in the context of compilers?
A) Selecting the appropriate data structures for the program
B) Ordering the instructions to optimize the performance of the target architecture
C) Assigning machine registers to variables
D) Generating intermediate code for the compiler
Answer: B) Ordering the instructions to optimize the performance of the target architecture
3. What does instruction scheduling aim to minimize?
A) The number of registers used
B) The number of machine instructions generated
C) The time required to execute the program
D) The number of syntax errors in the code
Answer: C) The time required to execute the program
4. Which of the following is a technique used for instruction selection?
A) Syntax tree traversal
B) Register allocation
C) Pattern matching based on instruction templates
D) Loop unrolling
Answer: C) Pattern matching based on instruction templates
5. What does “optimal instruction scheduling” mean?
A) Generating the fewest number of instructions
B) Arranging instructions so that the execution time is minimized, considering dependencies and available resources
C) Generating the simplest assembly code
D) Ensuring no redundant instructions are generated
Answer: B) Arranging instructions so that the execution time is minimized, considering dependencies and available resources
6. Which of the following is an important factor considered during instruction scheduling?
A) The number of variables used in the program
B) The number of registers available
C) Instruction dependencies, such as data and control dependencies
D) The memory size
Answer: C) Instruction dependencies, such as data and control dependencies
7. Which of the following is an example of a “data hazard” in instruction scheduling?
A) When an instruction depends on the result of a previous instruction
B) When an instruction is dependent on a conditional branch
C) When two instructions use the same register
D) When an instruction accesses memory before another instruction
Answer: A) When an instruction depends on the result of a previous instruction
8. What is the main challenge in instruction scheduling for modern processors?
A) Managing syntax errors
B) Reducing the number of instructions generated
C) Considering the processorās pipeline stages and available execution units
D) Allocating memory for variables
Answer: C) Considering the processorās pipeline stages and available execution units
9. Which of the following is a common technique used in instruction scheduling?
A) Loop unrolling
B) Software pipelining
C) Register renaming
D) Branch prediction
Answer: B) Software pipelining
10. What does “instruction latency” refer to in the context of instruction scheduling?
A) The number of instructions in a basic block
B) The delay between the issue of an instruction and its execution
C) The number of registers required by the program
D) The time taken to allocate a register for a variable
Answer: B) The delay between the issue of an instruction and its execution
11. Which of the following is true about the scheduling of dependent instructions?
A) Dependent instructions can be scheduled in any order
B) Dependent instructions must be scheduled in the order they appear in the source code
C) Dependent instructions must be scheduled in the order of their execution to avoid conflicts
D) Dependent instructions can be scheduled randomly
Answer: C) Dependent instructions must be scheduled in the order of their execution to avoid conflicts
12. In instruction selection, what is the role of “templates”?
A) They define the structure of machine-specific instructions
B) They represent the syntax of the source code
C) They are used for loop optimization
D) They handle error detection in intermediate code
Answer: A) They define the structure of machine-specific instructions
13. Which of the following is a disadvantage of poor instruction scheduling?
A) Reduced program size
B) Increased execution time due to pipeline stalls or resource conflicts
C) Reduced number of instructions
D) More efficient use of registers
Answer: B) Increased execution time due to pipeline stalls or resource conflicts
14. Which of the following statements best describes “post-RA (Register Allocation) instruction scheduling”?
A) Scheduling instructions after the machine code has been generated
B) Scheduling instructions to avoid memory bottlenecks
C) Scheduling instructions considering available registers
D) Scheduling instructions to reduce register spilling
Answer: C) Scheduling instructions considering available registers
15. What does the term “loop unrolling” refer to in instruction scheduling?
A) Breaking a loop into multiple smaller loops to improve parallelism
B) Merging multiple loops into a single loop
C) Increasing the number of iterations in a loop for better performance
D) Reducing the number of instructions within a loop
Answer: A) Breaking a loop into multiple smaller loops to improve parallelism