Cache array length in for loops can save gas #83
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0xKiwi
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duplicate of #198 |
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Handle
WatchPug
Vulnerability details
Reading array length at each iteration of the loop takes 6 gas (3 for mload and 3 to place memory_offset) in the stack.
Caching the array length in the stack saves around 3 gas per iteration.
Instances include:
NFTXVaultUpgradeable.sol#receiveNFTs()https://github.com/code-423n4/2021-12-nftx/blob/194073f750b7e2c9a886ece34b6382b4f1355f36/nftx-protocol-v2/contracts/solidity/NFTXVaultUpgradeable.sol#L406
https://github.com/code-423n4/2021-12-nftx/blob/194073f750b7e2c9a886ece34b6382b4f1355f36/nftx-protocol-v2/contracts/solidity/NFTXVaultUpgradeable.sol#L419
NFTXVaultUpgradeable.sol#withdrawNFTsTo()https://github.com/code-423n4/2021-12-nftx/blob/194073f750b7e2c9a886ece34b6382b4f1355f36/nftx-protocol-v2/contracts/solidity/NFTXVaultUpgradeable.sol#L442-L444
NFTXVaultUpgradeable.sol#swapTo()https://github.com/code-423n4/2021-12-nftx/blob/194073f750b7e2c9a886ece34b6382b4f1355f36/nftx-protocol-v2/contracts/solidity/NFTXVaultUpgradeable.sol#L267
NFTXStakingZap.sol#_addLiquidity721WETH()https://github.com/code-423n4/2021-12-nftx/blob/194073f750b7e2c9a886ece34b6382b4f1355f36/nftx-protocol-v2/contracts/solidity/NFTXStakingZap.sol#L341
NFTXLPStaking.sol#claimMultipleRewards()https://github.com/code-423n4/2021-12-nftx/blob/194073f750b7e2c9a886ece34b6382b4f1355f36/nftx-protocol-v2/contracts/solidity/NFTXLPStaking.sol#L206
NFTXMarketplaceZap.sol#_swap721()https://github.com/code-423n4/2021-12-nftx/blob/194073f750b7e2c9a886ece34b6382b4f1355f36/nftx-protocol-v2/contracts/solidity/NFTXMarketplaceZap.sol#L437
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