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code-423n4 / 2022-03-volt-findings

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Gas Optimizations #15

Open code423n4 opened 2 years ago

code423n4 commented 2 years ago

1) Long Revert Strings are Waste of Gas

Impact

Shortening revert strings to fit in 32 bytes will decrease deployment time gas and will decrease runtime gas when the revert condition has been met.

Revert strings that are longer than 32 bytes require at least one additional mstore, along with additional overhead for computing memory offset, etc.

Proof of Concept

https://github.com/code-423n4/2022-03-volt/blob/main/contracts/peg/NonCustodialPSM.sol#L117 https://github.com/code-423n4/2022-03-volt/blob/main/contracts/peg/NonCustodialPSM.sol#L123 https://github.com/code-423n4/2022-03-volt/blob/main/contracts/peg/NonCustodialPSM.sol#L239 https://github.com/code-423n4/2022-03-volt/blob/main/contracts/peg/NonCustodialPSM.sol#L277 https://github.com/code-423n4/2022-03-volt/blob/main/contracts/peg/NonCustodialPSM.sol#L402 https://github.com/code-423n4/2022-03-volt/blob/main/contracts/peg/NonCustodialPSM.sol#L415 https://github.com/code-423n4/2022-03-volt/blob/main/contracts/peg/NonCustodialPSM.sol#L428 https://github.com/code-423n4/2022-03-volt/blob/main/contracts/peg/NonCustodialPSM.sol#L441 https://github.com/code-423n4/2022-03-volt/blob/main/contracts/peg/NonCustodialPSM.sol#L445

Recommended Mitigation Steps

Shorten the revert strings to fit in 32 bytes.

ElliotFriedman commented 2 years ago

Agreed that these could be changed to save a bit of gas on the sad path.