SSA optimizer enhancements

[jserv]

This extends the SSA optimization framework with multiple optimization techniques that operate at the basic block level:

1. simple_sccp() - Implements Sparse Conditional Constant Propagation, performing constant propagation through assignments, constant folding for arithmetic and comparison operations, and branch folding when conditions are compile-time constants 2. eval_const_arithmetic() - Enhanced constant folding for binary operations including arithmetic (+, -, *, /, %), bitwise (<<, >>, &, |, ^), logical (&&, ||), and comparison operations (==, !=, <, <=, >, >=) with zero-division protection
2. eval_const_unary() - Constant folding for unary operations including negation (-), bitwise NOT (~), and logical NOT (!)
3. is_cse_candidate() - Identifies operations eligible for Common Subexpression Elimination across all binary operation types
4. cse() - Extended Common Subexpression Elimination supporting general binary operations with commutative operation detection for add, mul, bit_and, bit_or, bit_xor, log_and, log_or, eq, and neq

Summary by Bito

This pull request enhances the SSA optimization framework with multiple techniques at the basic block level, including Sparse Conditional Constant Propagation, improved constant folding, and Common Subexpression Elimination. Additionally, error handling has been refactored for better robustness, aiming to optimize performance and efficiency.