Worked on expanding backend capabilities in the bytecodealliance/wasmtime repository by implementing the 'cls' operation for all integer types within the Cranelift x64 backend. This enhancement broadened opcode support, directly improving code generation flexibility for low-level systems. The approach involved using Rust and applying principles of compiler design to ensure robust integration. Additionally, test suites were refactored and reorganized, consolidating i128-cls tests and improving the maintainability and reliability of continuous integration feedback. The work focused on both feature development and test infrastructure, resulting in more comprehensive coverage and streamlined test management for ongoing backend improvements.