Instruction Selection
What is the primary goal of instruction selection in a compiler?
A) To choose the most efficient machine instructions for a given intermediate representation
B) To generate assembly code
C) To optimize memory allocation
D) To handle function calls
Answer: A) To choose the most efficient machine instructions for a given intermediate representation
In the context of instruction selection, what is an “instruction pattern”?
A) A template used to match intermediate representations with target machine instructions
B) A method for generating intermediate code
C) A strategy for memory management
D) A technique for optimizing loops
Answer: A) A template used to match intermediate representations with target machine instructions
Which of the following techniques is used to improve the effectiveness of instruction selection?
A) Instruction pattern matching
B) Register allocation
C) Data flow analysis
D) Control flow analysis
Answer: A) Instruction pattern matching
What is a “cost model” in instruction selection?
A) A method to estimate the performance impact of different instruction sequences
B) A technique to generate intermediate code
C) A strategy to manage memory allocation
D) A tool for debugging
Answer: A) A method to estimate the performance impact of different instruction sequences
What does “target-independent code generation” mean in instruction selection?
A) Generating code that can be adapted to different target architectures
B) Generating code specific to a single target architecture
C) Optimizing memory usage
D) Handling function calls
Answer: A) Generating code that can be adapted to different target architectures
Instruction Scheduling
What is the primary purpose of instruction scheduling?
A) To arrange instructions in an optimal order to improve performance and minimize delays
B) To generate intermediate code
C) To handle function calls
D) To manage memory allocation
Answer: A) To arrange instructions in an optimal order to improve performance and minimize delays
What is “static instruction scheduling”?
A) Scheduling instructions based on compile-time information without considering runtime behavior
B) Scheduling instructions at runtime based on actual execution
C) Managing memory allocation
D) Handling function calls
Answer: A) Scheduling instructions based on compile-time information without considering runtime behavior
Which of the following is a common technique used in static instruction scheduling?
A) List scheduling
B) Register allocation
C) Data flow analysis
D) Code generation
Answer: A) List scheduling
What is “dynamic instruction scheduling”?
A) Scheduling instructions at runtime based on actual execution and runtime data
B) Scheduling instructions based on compile-time information
C) Managing memory allocation
D) Generating intermediate code
Answer: A) Scheduling instructions at runtime based on actual execution and runtime data
Which scheduling technique involves reordering instructions to avoid pipeline stalls?
A) Instruction-level parallelism
B) Loop unrolling
C) Dependency scheduling
D) Instruction fusion
Answer: C) Dependency scheduling
Techniques and Algorithms
What is “list scheduling” in the context of instruction scheduling?
A) A technique where instructions are scheduled based on a list of their dependencies and priorities
B) A method for generating intermediate code
C) A technique for memory management
D) A strategy for function calls
Answer: A) A technique where instructions are scheduled based on a list of their dependencies and priorities
What is the purpose of “software pipelining” in instruction scheduling?
A) To overlap the execution of loop iterations to improve performance
B) To manage memory allocation
C) To optimize function calls
D) To generate intermediate code
Answer: A) To overlap the execution of loop iterations to improve performance
In instruction scheduling, what does “loop unrolling” refer to?
A) A technique to increase instruction-level parallelism by expanding the loop body
B) A method for managing memory allocation
C) A technique to handle function calls
D) A strategy for code generation
Answer: A) A technique to increase instruction-level parallelism by expanding the loop body
What is “VLIW” in instruction scheduling?
A) Very Long Instruction Word, a type of architecture that allows multiple instructions to be executed simultaneously
B) Variable Length Instruction Word
C) Virtual Long Instruction Word
D) Vector Length Instruction Word
Answer: A) Very Long Instruction Word, a type of architecture that allows multiple instructions to be executed simultaneously
What is “out-of-order execution” in the context of instruction scheduling?
A) Executing instructions based on their availability rather than their original program order to improve performance
B) Executing instructions strictly in their original order
C) Managing memory allocation
D) Handling function calls
Answer: A) Executing instructions based on their availability rather than their original program order to improve performance
Performance Considerations
What is “instruction-level parallelism”?
A) The degree to which multiple instructions can be executed simultaneously
B) The degree to which functions can be executed simultaneously
C) The degree to which memory can be accessed simultaneously
D) The degree to which variables can be accessed simultaneously
Answer: A) The degree to which multiple instructions can be executed simultaneously
What is the main benefit of “speculative execution” in instruction scheduling?
A) To improve performance by executing instructions before it is certain that they are needed
B) To manage memory allocation more efficiently
C) To handle function calls
D) To generate intermediate code
Answer: A) To improve performance by executing instructions before it is certain that they are needed
How does “register renaming” contribute to instruction scheduling?
A) By reducing false dependencies and enabling more parallelism in instruction execution
B) By increasing memory access times
C) By simplifying code generation
D) By managing function calls
Answer: A) By reducing false dependencies and enabling more parallelism in instruction execution
What is the impact of “cache coherence” on instruction scheduling?
A) Ensuring that changes to data in caches are consistent across different processors or cores, which affects instruction scheduling and performance
B) Reducing the number of instructions executed
C) Simplifying memory allocation
D) Managing function calls
Answer: A) Ensuring that changes to data in caches are consistent across different processors or cores, which affects instruction scheduling and performance
What is “branch prediction” used for in instruction scheduling?
A) To predict the outcome of conditional branches and reduce pipeline stalls
B) To manage memory allocation
C) To handle function calls
D) To generate intermediate code
Answer: A) To predict the outcome of conditional branches and reduce pipeline stalls
Optimization Techniques
What is “trace scheduling”?
A) A technique to schedule instructions along frequently executed paths (traces) to improve performance
B) A method for managing memory allocation
C) A technique for generating intermediate code
D) A strategy for handling function calls
Answer: A) A technique to schedule instructions along frequently executed paths (traces) to improve performance
What does “dynamic scheduling” involve?
A) Scheduling instructions at runtime based on real-time execution information
B) Scheduling instructions at compile time
C) Managing memory allocation
D) Generating intermediate code
Answer: A) Scheduling instructions at runtime based on real-time execution information
What is “loop fusion” in instruction scheduling?
A) Combining multiple loops into a single loop to improve performance by reducing loop overhead
B) Separating loops to increase parallelism
C) Reducing the number of instructions executed
D) Handling function calls
Answer: A) Combining multiple loops into a single loop to improve performance by reducing loop overhead
What is “loop splitting” used for?
A) To break a loop into smaller loops to improve instruction scheduling and reduce register pressure
B) To combine multiple loops
C) To manage memory allocation
D) To handle function calls
Answer: A) To break a loop into smaller loops to improve instruction scheduling and reduce register pressure
What is “instruction fusion”?
A) Combining multiple instructions into a single instruction to reduce the number of instructions and improve performance
B) Splitting instructions into smaller units
C) Managing memory allocation more efficiently
D) Handling function calls
Answer: A) Combining multiple instructions into a single instruction to reduce the number of instructions and improve performance
Compiler Techniques
What is “instruction scheduling with register constraints”?
A) Scheduling instructions while considering constraints imposed by the availability of registers
B) Scheduling instructions without considering registers
C) Generating intermediate code
D) Managing memory allocation
Answer: A) Scheduling instructions while considering constraints imposed by the availability of registers
How does “peephole optimization” relate to instruction scheduling?
A) It involves making small local improvements to instruction sequences to enhance performance
B) It manages memory allocation
C) It handles function calls
D) It generates intermediate code
Answer: A) It involves making small local improvements to instruction sequences to enhance performance
What is the role of “post-pass optimization” in instruction scheduling?
A) To perform optimizations after the initial instruction scheduling to further enhance performance
B) To handle memory allocation
C) To generate intermediate code
D) To manage function calls
Answer: A) To perform optimizations after the initial instruction scheduling to further enhance performance
What is “function-level scheduling”?
A) Scheduling instructions at the level of entire functions to improve performance
B) Scheduling instructions within a single loop
C) Generating intermediate code
D) Managing memory allocation
Answer: A) Scheduling instructions at the level of entire functions to improve performance
What is “software pipelining” used for in the context of loops?
A) To overlap the execution of loop iterations to improve performance
B) To unroll loops
C) To manage memory allocation
D) To handle function calls
Answer: A) To overlap the execution of loop iterations to improve performance
Advanced Concepts
What is “superscalar architecture”?
A) An architecture that allows multiple instructions to be executed simultaneously in a single clock cycle
B) An architecture that executes instructions sequentially
C) An architecture focused on managing memory allocation
D) An architecture for handling function calls
Answer: A) An architecture that allows multiple instructions to be executed simultaneously in a single clock cycle
What is “out-of-order execution”?
A) A technique that allows instructions to be executed as resources are available, rather than strictly in the order they appear
B) Executing instructions in their original order
C) Managing memory allocation
D) Handling function calls
Answer: A) A technique that allows instructions to be executed as resources are available, rather than strictly in the order they appear
What is “branch prediction” used for in instruction scheduling?
A) To guess the direction of a branch to reduce pipeline stalls
B) To handle memory allocation
C) To manage function calls
D) To generate intermediate code
Answer: A) To guess the direction of a branch to reduce pipeline stalls
What does “loop unrolling” do?
A) It increases instruction-level parallelism by expanding the loop body
B) It reduces the number of instructions executed
C) It handles function calls
D) It manages memory allocation
Answer: A) It increases instruction-level parallelism by expanding the loop body
What is “loop interchange” in instruction scheduling?
A) Changing the order of nested loops to improve performance by improving cache utilization and parallelism
B) Combining multiple loops
C) Reducing the number of instructions executed
D) Handling function calls
Answer: A) Changing the order of nested loops to improve performance by improving cache utilization and parallelism
Miscellaneous
What is the main advantage of “instruction-level parallelism”?
A) It allows multiple instructions to be executed simultaneously, improving performance
B) It increases memory usage
C) It reduces the number of function calls
D) It simplifies code generation
Answer: A) It allows multiple instructions to be executed simultaneously, improving performance
What is “data dependence analysis” used for in instruction scheduling?
A) To determine dependencies between instructions to ensure correct execution order
B) To manage memory allocation
C) To handle function calls
D) To generate intermediate code
Answer: A) To determine dependencies between instructions to ensure correct execution order
How does “loop fusion” affect instruction scheduling?
A) It can improve performance by reducing loop overhead and increasing parallelism
B) It reduces the number of instructions executed
C) It manages memory allocation
D) It handles function calls
Answer: A) It can improve performance by reducing loop overhead and increasing parallelism
What is “register renaming” used to address in instruction scheduling?
A) It addresses false dependencies between instructions to improve parallelism
B) It simplifies memory management
C) It handles function calls
D) It generates intermediate code
Answer: A) It addresses false dependencies between instructions to improve parallelism
What is the goal of “out-of-order execution”?
A) To improve performance by executing instructions as soon as their operands are available, regardless of their original order
B) To ensure instructions are executed in their original order
C) To manage memory allocation
D) To handle function calls
Answer: A) To improve performance by executing instructions as soon as their operands are available, regardless of their original order
Advanced Scheduling Techniques
What is “trace scheduling”?
A) Scheduling frequently executed paths (traces) in the code to improve performance
B) Managing memory allocation
C) Generating intermediate code
D) Handling function calls
Answer: A) Scheduling frequently executed paths (traces) in the code to improve performance
What does “loop blocking” aim to achieve?
A) It aims to improve cache performance by dividing loops into smaller blocks
B) It reduces the number of instructions executed
C) It simplifies function calls
D) It manages memory allocation
Answer: A) It aims to improve cache performance by dividing loops into smaller blocks
What is the purpose of “software pipelining”?
A) To overlap the execution of loop iterations to increase performance
B) To manage memory allocation more efficiently
C) To simplify function calls
D) To generate intermediate code
Answer: A) To overlap the execution of loop iterations to increase performance
What does “register allocation” involve in the context of instruction scheduling?
A) Allocating a limited number of registers to hold variables and intermediate results to minimize memory access
B) Scheduling instructions to improve performance
C) Managing function calls
D) Generating intermediate code
Answer: A) Allocating a limited number of registers to hold variables and intermediate results to minimize memory access
What is “instruction fusion”?
A) Combining multiple instructions into a single instruction to reduce the number of instructions and improve performance
B) Splitting instructions into smaller units
C) Managing memory allocation
D) Handling function calls
Answer: A) Combining multiple instructions into a single instruction to reduce the number of instructions and improve performance
Performance and Optimization
What is “pipeline stall”?
A) A delay that occurs in a pipeline when the next instruction cannot be executed due to dependencies or resource constraints
B) A technique to optimize function calls
C) A method for managing memory allocation
D) A strategy for generating intermediate code
Answer: A) A delay that occurs in a pipeline when the next instruction cannot be executed due to dependencies or resource constraints
What is “speculative execution”?
A) Executing instructions before it is certain they are needed to improve performance
B) Managing memory allocation
C) Handling function calls
D) Generating intermediate code
Answer: A) Executing instructions before it is certain they are needed to improve performance
What does “loop invariant code motion” aim to achieve?
A) Moving computations that do not change across loop iterations outside of the loop to improve performance
B) Reducing the number of function calls
C) Simplifying memory management
D) Handling function calls
Answer: A) Moving computations that do not change across loop iterations outside of the loop to improve performance
How does “data dependence” affect instruction scheduling?
A) It determines the order in which instructions must be executed to ensure correct results
B) It simplifies memory management
C) It reduces the number of instructions executed
D) It handles function calls
Answer: A) It determines the order in which instructions must be executed to ensure correct results
What is “instruction selection” in the context of code generation?
A) The process of choosing the most efficient machine instructions for a given intermediate representation
B) The process of generating intermediate code
C) The process of managing memory allocation
D) The process of handling function calls
Answer: A) The process of choosing the most efficient machine instructions for a given intermediate representation