Gas Optimization: > 0 is less efficient than != 0 for uint in require condition

[code423n4]

Handle

gzeon

Vulnerability details

Impact

> 0 is less gas efficient than != 0 for uint in require condition when optimizer is enabled
Ref: https://twitter.com/GalloDaSballo/status/1485430908165443590

Proof of Concept

$ grep -Rn "> 0" ./contracts | grep require
./contracts/ControllerV1.sol:311:        require(rewards > 0, 'rewards is zero');
./contracts/ControllerV1.sol:342:        require(supplyAmount > 0 || borrowAmount > 0, 'amount is less than 0');
./contracts/ControllerV1.sol:358:        require(supplyAmount > 0 || borrowAmount > 0, 'amount0 and amount1 is 0');
./contracts/dex/bsc/UniV2ClassDex.sol:199:        require(amountIn > 0, 'INSUFFICIENT_INPUT_AMOUNT');
./contracts/dex/bsc/UniV2ClassDex.sol:200:        require(reserveIn > 0 && reserveOut > 0, 'INSUFFICIENT_LIQUIDITY');
./contracts/dex/bsc/UniV2ClassDex.sol:208:        require(amountOut > 0, 'INSUFFICIENT_OUTPUT_AMOUNT');
./contracts/dex/bsc/UniV2ClassDex.sol:209:        require(reserveIn > 0 && reserveOut > 0, 'INSUFFICIENT_LIQUIDITY');
./contracts/dex/eth/UniV2Dex.sol:197:        require(amountIn > 0, 'INSUFFICIENT_INPUT_AMOUNT');
./contracts/dex/eth/UniV2Dex.sol:198:        require(reserveIn > 0 && reserveOut > 0, 'INSUFFICIENT_LIQUIDITY');
./contracts/dex/eth/UniV2Dex.sol:206:        require(amountOut > 0, 'INSUFFICIENT_OUTPUT_AMOUNT');
./contracts/dex/eth/UniV2Dex.sol:207:        require(reserveIn > 0 && reserveOut > 0, 'INSUFFICIENT_LIQUIDITY');
./contracts/dex/eth/UniV3Dex.sol:126:        require(secondsAgo > 0, "SecondsAgo must >0");
./contracts/dex/eth/UniV3Dex.sol:165:        require(amount0Delta > 0 || amount1Delta > 0);
./contracts/farming/FarmingPools.sol:96:        require(amount > 0, "Cannot stake 0");
./contracts/farming/FarmingPools.sol:104:        require(amount > 0, "Cannot withdraw 0");
./contracts/gov/GovernorAlpha.sol:248:        require(proposalCount >= proposalId && proposalId > 0, "GovernorAlpha::state: invalid proposal id");
./contracts/lib/Exponential.sol:346:        require(b > 0, errorMessage);
./contracts/liquidity/LPool.sol:57:        require(initialExchangeRateMantissa > 0, "Initial Exchange Rate Mantissa should be greater zero");
./contracts/OLETokenLock.sol:46:        require(amount > 0, "no amount available");
./contracts/OLETokenLock.sol:57:        require(releaseVars[beneficiary].amount > 0, 'beneficiary does not exist');
./contracts/OLETokenLock.sol:75:        require(releaseVar.amount > 0, "beneficiary does not exist");
./contracts/OpenLevV1Lib.sol:81:        require(defaultFeesRate < 10000 && insuranceRatio < 100 && defaultMarginLimit > 0 && updatePriceDiscount <= 100
./contracts/OpenLevV1Lib.sol:112:        require(feesRate < 10000 && marginLimit > 0 && dexs.length > 0, 'PRI');
./contracts/OpenLevV1Lib.sol:297:            require(borrow > 0, "BB0");
./contracts/Reserve.sol:32:        require(amount > 0, "amount is 0!");
./contracts/test/MockTaxToken.sol:348:        require(amount > 0, "Transfer amount must be greater than zero");
./contracts/test/MockUniswapV3Factory.sol:71:        require(tickSpacing > 0 && tickSpacing < 16384);
./contracts/test/MockUniswapV3Pair.sol:826:require(_liquidity > 0, 'L');
./contracts/XOLE.sol:71:        require(totalSupply > 0, "Can't share without locked OLE");
./contracts/XOLE.sol:252:        require(_value > 0, "Non zero value");
./contracts/XOLE.sol:266:        require(_value > 0, "need non - zero value");
./contracts/XOLE.sol:267:        require(_locked.amount > 0, "No existing lock found");
./contracts/XOLE.sol:279:        require(_locked.amount > 0, "Nothing is locked");

[ColaM12]

Duplicate to #21