Gas Optimizations

[code423n4]

1. Title : Shorter code can be save more gas

1.) File : contracts/core/connext/facets/BridgeFacet.sol Line. 843

        _amount = _amount + sponsored;

change to :

_amount += sponsored:

2. Title : Saving gas by removing = 0

This implementation code can be saving more gas by removing = 0, it because If a variable was not set/initialized, it is assumed to have default value to 0

Tool Used

Manual Review

Mitigation Step

Remove = 0

Occurances

core/connext/facets/BridgeFacet.sol#L1103        backUnbackedDebt = 0;
core/connext/facets/BridgeFacet.sol#L1108        portalFee = 0;
contracts/core/connext/facets/BridgeFacet.sol#L1046      amountIn = 0;
contracts/core/connext/facets/PortalFacet.sol#L154        _feeAmount = 0;
contracts/core/connext/facets/ProposedOwnableFacet.sol#L272    s._routerOwnershipTimestamp = 0;
contracts/core/connext/facets/ProposedOwnableFacet.sol#L283    s._assetOwnershipTimestamp = 0;
contracts/core/connext/facets/ProposedOwnableFacet.sol#L288    s._proposedOwnershipTimestamp = 0;

3. Title : Using short reason string can be used for saving more gas

Every reason string takes at least 32 bytes. Use short reason strings that fits in 32 bytes or it will become more expensive.

Tool Used

Manual Review

Occurances

contracts/core/connext/libraries/SwapUtils.sol#L342 "Balances must match multipliers"
contracts/core/connext/libraries/SwapUtils.sol#L595 "Cannot withdraw more than available"
contracts/core/connext/libraries/SwapUtils.sol#L649 "Cannot swap more than you own"
contracts/core/connext/libraries/SwapUtils.sol#L662 "Swap didn't result in min tokens"
contracts/core/connext/libraries/SwapUtils.sol#L697 "Cannot get more than pool balance"
contracts/core/connext/libraries/SwapUtils.sol#L703 "Swap needs more than max tokens"
contracts/core/connext/libraries/SwapUtils.sol#L716 "Cannot swap more than you own"
contracts/core/connext/libraries/SwapUtils.sol#L750 "Cannot swap more than you own"
contracts/core/connext/libraries/SwapUtils.sol#L756 "Swap didn't result in min tokens"
contracts/core/connext/libraries/SwapUtils.sol#L784 "Cannot get more than pool balance"
contracts/core/connext/libraries/SwapUtils.sol#L790 "Swap didn't result in min tokens"
contracts/core/connext/libraries/SwapUtils.sol#L823 "Amounts must match pooled tokens"
contracts/core/connext/libraries/SwapUtils.sol#L917 "minAmounts must match poolTokens"
contracts/core/connext/libraries/SwapUtils.sol#L1005 "Amounts should match pool tokens"
contracts/core/connext/libraries/SwapUtils.sol#L1015  "Cannot withdraw more than available"
contracts/core/connext/libraries/AmplificationUtils.sol#L86 "futureA_ must be > 0 and < MAX_A"
contracts/core/connext/libraries/AmplificationUtils.sol#L84 "Wait 1 day before starting ramp"

[liu-zhipeng]

Duplicated