What are the advantages of code optimization. Define Dead-code elimination.

Code optimization enhances program efficiency by improving execution speed, reducing resource consumption, and minimizing code size while maintaining functionality. Dead-code elimination is a specific optimization technique that removes unnecessary code segments. Here's a detailed breakdown:

Advantages of Code Optimization

• Improved performance: Optimized code executes faster by eliminating redundant computations and streamlining operations.
• Reduced resource consumption: Lowers CPU usage and memory requirements through efficient instruction selection and register allocation.
• Smaller code size: Removes unnecessary operations and dead code, reducing program footprint.
• Enhanced portability: Creates more adaptable code for different processor architectures.
• Better maintainability: Simplified code structure through optimizations like common subexpression elimination.
• Energy efficiency: Reduced computations lead to lower power consumption in resource-constrained environments.

Optimization must balance performance gains with code readability and debugability, as aggressive changes can complicate maintenance.

Dead-Code Elimination

A compiler optimization technique that removes:

1. Unreachable code: Segments never executed due to program logic (e.g., code after return statements)[4][6].
2. Unused results: Computations whose outputs are never subsequently used.

Example:

// Original
int calc() {
    int a = 5*3;  // Dead code (never used)
    return 10;
    int b = 20;   // Unreachable
}

// Optimized
int calc() {
    return 10;
}

Benefits of Dead-Code Elimination

• Faster execution: Avoids unnecessary computations
• Reduced memory usage: Eliminates unused variable storage
• Simplified debugging: Removes distracting code artifacts
• Enables further optimizations: Creates cleaner code structure for subsequent transformations

However, compilers must preserve program semantics - code affecting global state or potential exceptions remains intact despite appearing dead. Modern IDEs like Visual Studio and Eclipse implement this through static analysis of control/data flow.