Code Optimization

General Concepts What is the main goal of code optimization? A) To increase the size of the code B) To make the code more readable C) To improve the performance and efficiency of the code D) To simplify the syntax Answer: C) To improve the performance and efficiency of the code Which of the following is NOT a common optimization goal? A) Reducing execution time B) Minimizing memory usage C) Increasing code complexity D) Enhancing code maintainability Answer: C) Increasing code complexity What does “loop unrolling” aim to achieve? A) To increase the number of loop iterations B) To reduce the overhead of loop control C) To replace loops with recursive functions D) To add additional loop variables Answer: B) To reduce the overhead of loop control Which technique involves replacing a sequence of instructions with a single, more efficient instruction? A) Peephole optimization B) Constant folding C) Loop fusion D) Dead code elimination Answer: A) Peephole optimization What is “constant folding” in the context of optimization? A) Evaluating constant expressions at compile time rather than runtime B) Increasing the number of constants in the code C) Converting constants into variables D) Removing constants from the code Answer: A) Evaluating constant expressions at compile time rather than runtime Loop Optimization What does “loop fusion” involve? A) Combining multiple loops with the same iteration space into a single loop B) Splitting a loop into smaller loops C) Increasing the number of loops in the code D) Removing all loops Answer: A) Combining multiple loops with the same iteration space into a single loop How does “loop invariant code motion” help in optimization? A) By moving computations that do not change within the loop outside of the loop B) By increasing the number of computations within the loop C) By converting loops into conditionals D) By adding more loop iterations Answer: A) By moving computations that do not change within the loop outside of the loop What is the purpose of “loop unrolling”? A) To reduce the number of loop control instructions and increase performance B) To increase the number of loop iterations C) To convert loops into recursive functions D) To add more loop variables Answer: A) To reduce the number of loop control instructions and increase performance Which optimization technique involves removing redundant operations inside a loop? A) Loop invariant code motion B) Loop unrolling C) Constant folding D) Dead code elimination Answer: A) Loop invariant code motion What is “loop peeling”? A) Separating a few iterations of a loop to simplify its body B) Increasing the number of iterations in a loop C) Converting loops into conditionals D) Adding additional loop control variables Answer: A) Separating a few iterations of a loop to simplify its body Code Simplification What is the purpose of “dead code elimination”? A) To remove code that does not affect the program’s outcome B) To increase the complexity of the code C) To add additional code paths D) To manage function parameters Answer: A) To remove code that does not affect the program’s outcome What does “common subexpression elimination” do? A) Replaces duplicate expressions with a single computation B) Increases the number of expressions in the code C) Converts expressions into function calls D) Adds additional arithmetic operations Answer: A) Replaces duplicate expressions with a single computation What is the goal of “strength reduction”? A) To replace expensive operations with less expensive ones B) To increase the number of arithmetic operations C) To add more complex operations D) To convert operations into function calls Answer: A) To replace expensive operations with less expensive ones Which technique involves simplifying complex conditional expressions? A) Conditional simplification B) Common subexpression elimination C) Constant folding D) Loop unrolling Answer: A) Conditional simplification What is “function inlining”? A) Replacing a function call with the function’s code to avoid the overhead of the call B) Converting functions into loops C) Increasing the number of function parameters D) Removing function calls entirely Answer: A) Replacing a function call with the function’s code to avoid the overhead of the call Data Flow Optimization What is the primary goal of “register allocation”? A) To assign variables to CPU registers for faster access B) To increase the number of variables in the code C) To manage stack space for function calls D) To optimize loop performance Answer: A) To assign variables to CPU registers for faster access What is “escape analysis” used for in optimization? A) To determine the lifetime of variables and optimize memory usage B) To manage function call parameters C) To handle recursion D) To increase the number of function calls Answer: A) To determine the lifetime of variables and optimize memory usage Which optimization technique focuses on reducing memory access time by improving data locality? A) Data locality optimization B) Loop unrolling C) Function inlining D) Constant propagation Answer: A) Data locality optimization What does “dead store elimination” refer to in optimization? A) Removing code that writes to memory but does not read from it B) Increasing the number of memory writes C) Converting writes to memory into function calls D) Adding more memory accesses Answer: A) Removing code that writes to memory but does not read from it What is the purpose of “value numbering”? A) To identify and eliminate redundant calculations by tracking the values of expressions B) To increase the number of variables in the code C) To convert values into constants D) To manage stack space Answer: A) To identify and eliminate redundant calculations by tracking the values of expressions Advanced Techniques What is “partial redundancy elimination”? A) Removing redundant computations that occur across different paths of control flow B) Adding more redundant computations C) Converting computations into function calls D) Simplifying conditional statements Answer: A) Removing redundant computations that occur across different paths of control flow How does “profile-guided optimization” enhance performance? A) By using runtime profiling information to guide optimizations B) By increasing the number of function calls C) By simplifying control flow constructs D) By converting all code to machine code Answer: A) By using runtime profiling information to guide optimizations What does “speculative execution” involve? A) Executing code paths before they are known to be needed to improve performance B) Increasing the number of conditional branches C) Removing all conditional checks D) Converting execution to loops Answer: A) Executing code paths before they are known to be needed to improve performance What is “loop fusion”? A) Combining multiple loops with the same iteration space into a single loop B) Splitting a loop into smaller loops C) Converting loops into conditionals D) Adding more loops to the code Answer: A) Combining multiple loops with the same iteration space into a single loop Which optimization technique is used to avoid unnecessary recomputation by caching results? A) Memoization B) Loop unrolling C) Strength reduction D) Function inlining Answer: A) Memoization Control Flow Optimization What does “branch prediction” aim to achieve in code optimization? A) To guess the direction of branches to minimize pipeline stalls and improve performance B) To increase the number of branches in the code C) To remove all conditional branches D) To convert branches into loops Answer: A) To guess the direction of branches to minimize pipeline stalls and improve performance How does “instruction scheduling” improve performance? A) By rearranging instructions to minimize pipeline stalls and improve parallelism B) By adding more instructions to the code C) By increasing the number of conditional branches D) By converting instructions into function calls Answer: A) By rearranging instructions to minimize pipeline stalls and improve parallelism What is “branch folding” in the context of optimization? A) Combining multiple branches into a single branch to simplify control flow B) Increasing the number of branches in the code C) Converting branches into loops D) Removing all branches from the code Answer: A) Combining multiple branches into a single branch to simplify control flow What does “instruction fusion” refer to in optimization? A) Combining multiple instructions into a single instruction to improve performance B) Adding more instructions to the code C) Removing all instructions D) Converting instructions into function calls Answer: A) Combining multiple instructions into a single instruction to improve performance What is the purpose of “loop splitting”? A) To divide a loop into multiple smaller loops to improve performance B) To increase the number of iterations in a loop C) To convert loops into conditionals D) To add more loop control variables Answer: A) To divide a loop into multiple smaller loops to improve performance Miscellaneous Which optimization technique involves removing unnecessary calculations from the code? A) Redundant computation elimination B) Loop unrolling C) Function inlining D) Constant folding Answer: A) Redundant computation elimination What is “register spilling”? A) The process of moving data from registers to memory when there are not enough registers available B) Adding more registers to the CPU C) Increasing the number of memory accesses D) Converting registers into memory variables Answer: A) The process of moving data from registers to memory when there are not enough registers available Which technique is used to optimize the usage of cache memory? A) Cache blocking B) Loop unrolling C) Function inlining D) Constant folding Answer: A) Cache blocking What is the purpose of “code motion”? A) To move computations out of loops or conditionals to avoid redundant execution B) To add more computations inside loops C) To convert code into recursive functions D) To simplify control flow Answer: A) To move computations out of loops or conditionals to avoid redundant execution Which optimization technique focuses on improving the execution of frequently executed paths of code? A) Hot path optimization B) Function inlining C) Loop fusion D) Dead code elimination Answer: A) Hot path optimization What is “data flow analysis” used for in optimization? A) To track how data moves through a program and optimize its usage B) To increase the number of variables in the code C) To manage memory allocation D) To convert code into assembly language Answer: A) To track how data moves through a program and optimize its usage Which technique involves using runtime information to guide optimization decisions? A) Profile-guided optimization B) Constant folding C) Function inlining D) Loop unrolling Answer: A) Profile-guided optimization What is the main benefit of “interprocedural optimization”? A) To optimize across function boundaries and improve overall performance B) To simplify function calls C) To increase the number of function parameters D) To convert functions into loops Answer: A) To optimize across function boundaries and improve overall performance What does “register promotion” involve? A) Moving variables from memory to registers to improve performance B) Increasing the number of memory accesses C) Converting registers into memory variables D) Adding more registers to the CPU Answer: A) Moving variables from memory to registers to improve performance Which technique involves analyzing and optimizing code paths that are executed most frequently? A) Hot path optimization B) Dead code elimination C) Constant folding D) Loop unrolling Answer: A) Hot path optimization What is “constant propagation”? A) Replacing variables with their constant values throughout the code B) Increasing the number of constants in the code C) Converting constants into variables D) Removing constants from the code Answer: A) Replacing variables with their constant values throughout the code Which technique involves combining operations into a single instruction for efficiency? A) Instruction fusion B) Loop unrolling C) Dead code elimination D) Function inlining Answer: A) Instruction fusion What is the purpose of “branch folding” in optimization? A) To combine multiple branches into a single branch to simplify control flow B) To increase the number of branches in the code C) To remove all branches from the code D) To convert branches into loops Answer: A) To combine multiple branches into a single branch to simplify control flow What does “loop interchange” involve? A) Swapping the order of nested loops to improve performance B) Increasing the number of loops in the code C) Converting loops into conditionals D) Adding more loop control variables Answer: A) Swapping the order of nested loops to improve performance Which technique helps to optimize the execution of branch instructions by guessing their outcome? A) Branch prediction B) Loop unrolling C) Function inlining D) Dead code elimination Answer: A) Branch prediction What is “data layout optimization” used for? A) To arrange data structures in memory to improve access patterns and performance B) To increase the number of data structures in the code C) To convert data structures into functions D) To remove data structures from the code Answer: A) To arrange data structures in memory to improve access patterns and performance What does “instruction scheduling” aim to achieve in optimization? A) To arrange instructions to minimize pipeline stalls and maximize parallelism B) To increase the number of instructions C) To convert instructions into function calls D) To add more conditional branches Answer: A) To arrange instructions to minimize pipeline stalls and maximize parallelism Which technique involves reducing the number of instructions executed by combining similar instructions? A) Instruction fusion B) Loop unrolling C) Constant folding D) Function inlining Answer: A) Instruction fusion What is the main purpose of “instruction-level parallelism”? A) To execute multiple instructions simultaneously to improve performance B) To increase the number of instructions in the code C) To simplify instruction execution D) To convert instructions into loops Answer: A) To execute multiple instructions simultaneously to improve performance What does “compile-time optimization” refer to? A) Performing optimizations during the compilation process rather than at runtime B) Executing code at runtime to optimize performance C) Adding more runtime checks D) Converting compiled code into assembly language Answer: A) Performing optimizations during the compilation process rather than at runtime