solidity-gas-optimization

Start with storage optimizations: avoid zero-to-one writes, cache storage variables read more than once, pack structs and slots, and use constant or immutable for never-updated values. Then review loops, requires, and cross-contract calls, benchmarking each change with forge test --gas-report.

The largest wins come from avoiding zero-to-non-zero storage writes (up to 17,100 gas saved), packing storage slots (20,000+ gas per avoided slot), caching redundant storage reads, and using custom errors instead of require strings. Design-level changes like ERC1155 or multicall batching can save even more.

Inline assembly saves gas in specific cases like reverts, external calls, and branchless math, but it removes compiler safety checks such as extcodesize verification and memory pointer management. Use it only after Solidity-level techniques, and always benchmark both versions.

No, smaller integer types do not save gas on operations because the EVM works in 32-byte words and the compiler inserts masking operations. Small types only save gas when two or more of them pack into the same storage slot.

No, many tricks are version-dependent. For example, external vs public and != 0 vs > 0 no longer differ in modern compilers, and Solidity 0.8.22 auto-optimizes for-loops. The --via-ir flag can also invert results, so always benchmark on your target version.

Avoid aggressive optimization for rarely-called admin functions where readability matters more, and never use contest-grade techniques like encoding data in msg.value or ignoring send() return values in production code. These introduce loss-of-funds and correctness risks.