Platform: Code4rena
Start Date: 16/02/2023
Pot Size: $144,750 USDC
Total HM: 17
Participants: 154
Period: 19 days
Judge: Trust
Total Solo HM: 5
Id: 216
League: ETH
Rank: 128/154
Findings: 1
Award: $42.07
🌟 Selected for report: 0
🚀 Solo Findings: 0
🌟 Selected for report: c3phas
Also found by: 0x3b, 0x6980, 0x73696d616f, 0xSmartContract, 0xackermann, 0xhacksmithh, 0xsomeone, Bnke0x0, Bough, Budaghyan, Darshan, DeFiHackLabs, Deivitto, GalloDaSballo, JCN, LethL, Madalad, MiniGlome, Morraez, P-384, PaludoX0, Phantasmagoria, Praise, RHaO-sec, Rageur, RaymondFam, ReyAdmirado, Rickard, Rolezn, SaeedAlipoor01988, Saintcode_, Sathish9098, TheSavageTeddy, Tomio, Viktor_Cortess, abiih, arialblack14, atharvasama, banky, codeislight, cryptonue, ddimitrov22, dec3ntraliz3d, descharre, dharma09, emmac002, favelanky, hl_, hunter_w3b, kaden, kodyvim, matrix_0wl, oyc_109, pavankv, scokaf, seeu, yamapyblack
42.0697 USDC - $42.07
Consider marking constant variables in storage as private to save gas (unless a constant variable should be easily accessible by another protocol or offchain logic).
contract GasTest is DSTest { Contract0 c0; Contract1 c1; function setUp() public { c0 = new Contract0(); c1 = new Contract1(); } function testGas() public view { uint256 a = 100; c0.addPublicConstant(a); c1.addPrivateConstant(a); } } contract Contract0 { uint256 constant public x = 100; function addPublicConstant(uint256 a) external pure returns (uint256) { return a + x; } } contract Contract1 { uint256 constant private x = 100; function addPrivateConstant(uint256 a) external pure returns (uint256) { return a +x; } }
╭───────────────────────────────────────────┬─────────────────┬─────┬────────┬─────┬─────────╮ │ src/test/GasTest.t.sol:Contract0 contract ┆ ┆ ┆ ┆ ┆ │ ╞═══════════════════════════════════════════╪═════════════════╪═════╪════════╪═════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 92741 ┆ 495 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ addPublicConstant ┆ 790 ┆ 790 ┆ 790 ┆ 790 ┆ 1 │ ╰───────────────────────────────────────────┴─────────────────┴─────┴────────┴─────┴─────────╯ ╭───────────────────────────────────────────┬─────────────────┬─────┬────────┬─────┬─────────╮ │ src/test/GasTest.t.sol:Contract1 contract ┆ ┆ ┆ ┆ ┆ │ ╞═══════════════════════════════════════════╪═════════════════╪═════╪════════╪═════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 83535 ┆ 449 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ addPrivateConstant ┆ 768 ┆ 768 ┆ 768 ┆ 768 ┆ 1 │ ╰───────────────────────────────────────────┴─────────────────┴─────┴────────┴─────┴─────────╯
unchecked{++i}
instead of i++
(or use assembly when applicable)Use ++i
instead of i++
. This is especially useful in for loops but this optimization can be used anywhere in your code. You can also use unchecked{++i;}
for even more gas savings but this will not check to see if i
overflows. For extra safety if you are worried about this, you can add a require statement after the loop checking if i
is equal to the final incremented value. For best gas savings, use inline assembly, however this limits the functionality you can achieve. For example you cant use Solidity syntax to internally call your own contract within an assembly block and external calls must be done with the call()
or delegatecall()
instruction. However when applicable, inline assembly will save much more gas.
contract GasTest is DSTest { Contract0 c0; Contract1 c1; Contract2 c2; Contract3 c3; Contract4 c4; function setUp() public { c0 = new Contract0(); c1 = new Contract1(); c2 = new Contract2(); c3 = new Contract3(); c4 = new Contract4(); } function testGas() public { c0.iPlusPlus(); c1.plusPlusI(); c2.uncheckedPlusPlusI(); c3.safeUncheckedPlusPlusI(); c4.inlineAssemblyLoop(); } } contract Contract0 { //loop with i++ function iPlusPlus() public pure { uint256 j = 0; for (uint256 i; i < 10; i++) { j++; } } } contract Contract1 { //loop with ++i function plusPlusI() public pure { uint256 j = 0; for (uint256 i; i < 10; ++i) { j++; } } } contract Contract2 { //loop with unchecked{++i} function uncheckedPlusPlusI() public pure { uint256 j = 0; for (uint256 i; i < 10; ) { j++; unchecked { ++i; } } } } contract Contract3 { //loop with unchecked{++i} with additional overflow check function safeUncheckedPlusPlusI() public pure { uint256 j = 0; uint256 i = 0; for (i; i < 10; ) { j++; unchecked { ++i; } } //check for overflow assembly { if lt(i, 10) { mstore(0x00, "loop overflow") revert(0x00, 0x20) } } } } contract Contract4 { //loop with inline assembly function inlineAssemblyLoop() public pure { assembly { let j := 0 for { let i := 0 } lt(i, 10) { i := add(i, 0x01) } { j := add(j, 0x01) } } } }
╭────────────────────┬─────────────────┬──────┬────────┬──────┬─────────╮ │ Contract0 contract ┆ ┆ ┆ ┆ ┆ │ ╞════════════════════╪═════════════════╪══════╪════════╪══════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 37687 ┆ 219 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ iPlusPlus ┆ 2039 ┆ 2039 ┆ 2039 ┆ 2039 ┆ 1 │ ╰────────────────────┴─────────────────┴──────┴────────┴──────┴─────────╯ ╭────────────────────┬─────────────────┬──────┬────────┬──────┬─────────╮ │ Contract1 contract ┆ ┆ ┆ ┆ ┆ │ ╞════════════════════╪═════════════════╪══════╪════════╪══════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 37287 ┆ 217 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ plusPlusI ┆ 1989 ┆ 1989 ┆ 1989 ┆ 1989 ┆ 1 │ ╰────────────────────┴─────────────────┴──────┴────────┴──────┴─────────╯ ╭────────────────────────┬─────────────────┬──────┬────────┬──────┬─────────╮ │ Contract3 contract ┆ ┆ ┆ ┆ ┆ │ ╞════════════════════════╪═════════════════╪══════╪════════╪══════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 42693 ┆ 244 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ safeUncheckedPlusPlusI ┆ 1355 ┆ 1355 ┆ 1355 ┆ 1355 ┆ 1 │ ╰────────────────────────┴─────────────────┴──────┴────────┴──────┴─────────╯ ╭────────────────────┬─────────────────┬──────┬────────┬──────┬─────────╮ │ Contract2 contract ┆ ┆ ┆ ┆ ┆ │ ╞════════════════════╪═════════════════╪══════╪════════╪══════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 35887 ┆ 210 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ uncheckedPlusPlusI ┆ 1329 ┆ 1329 ┆ 1329 ┆ 1329 ┆ 1 │ ╰────────────────────┴─────────────────┴──────┴────────┴──────┴─────────╯ ╭────────────────────┬─────────────────┬─────┬────────┬─────┬─────────╮ │ Contract4 contract ┆ ┆ ┆ ┆ ┆ │ ╞════════════════════╪═════════════════╪═════╪════════╪═════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 26881 ┆ 164 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ inlineAssemblyLoop ┆ 709 ┆ 709 ┆ 709 ┆ 709 ┆ 1 │ ╰────────────────────┴─────────────────┴─────┴────────┴─────┴─────────╯
When defining storage variables, make sure to declare them in ascending order, according to size. When multiple variables are able to fit into one 256 bit slot, this will save storage size and gas during runtime. For example, if you have a bool
, uint256
and a bool
, instead of defining the variables in the previously mentioned order, defining the two boolean variables first will pack them both into one storage slot since they only take up one byte of storage.
contract GasTest is DSTest { Contract0 c0; Contract1 c1; function setUp() public { c0 = new Contract0(); c1 = new Contract1(); } function testGas() public { bool bool0 = true; bool bool1 = false; uint256 num0 = 200; uint256 num1 = 100; c0.accessNonTightlyPacked(bool0, bool1, num0, num1); c1.accessTightlyPacked(bool0, bool1, num0, num1); } } contract Contract0 { uint256 num0 = 100; bool bool0 = false; uint256 num1 = 200; bool bool1 = true; function accessNonTightlyPacked( bool _bool0, bool _bool1, uint256 _num0, uint256 _num1 ) public { bool0 = _bool0; bool1 = _bool1; num0 = _num0; num1 = _num1; } } contract Contract1 { bool bool0 = false; bool bool1 = true; uint256 num0 = 100; uint256 num1 = 200; function accessTightlyPacked( bool _bool0, bool _bool1, uint256 _num0, uint256 _num1 ) public { bool0 = _bool0; bool1 = _bool1; num0 = _num0; num1 = _num1; } }
╭───────────────────────────────────────────┬─────────────────┬───────┬────────┬───────┬─────────╮ │ src/test/GasTest.t.sol:Contract0 contract ┆ ┆ ┆ ┆ ┆ │ ╞═══════════════════════════════════════════╪═════════════════╪═══════╪════════╪═══════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 122268 ┆ 334 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ accessNonTightlyPacked ┆ 32774 ┆ 32774 ┆ 32774 ┆ 32774 ┆ 1 │ ╰───────────────────────────────────────────┴─────────────────┴───────┴────────┴───────┴─────────╯ ╭───────────────────────────────────────────┬─────────────────┬───────┬────────┬───────┬─────────╮ │ src/test/GasTest.t.sol:Contract1 contract ┆ ┆ ┆ ┆ ┆ │ ╞═══════════════════════════════════════════╪═════════════════╪═══════╪════════╪═══════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 126247 ┆ 356 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ accessTightlyPacked ┆ 15476 ┆ 15476 ┆ 15476 ┆ 15476 ┆ 1 │ ╰───────────────────────────────────────────┴─────────────────┴───────┴────────┴───────┴─────────╯
A typical for loop definition may look like: for (uint256 i; i < arr.length; i++){}
. Instead of using array.length
, cache the array length before the loop, and use the cached value to safe gas. This will avoid an MLOAD
every loop for arrays stored in memory and an SLOAD
for arrays stored in storage. This can have significant gas savings for arrays with a large length, especially if the array is stored in storage.
contract GasTest is DSTest { Contract0 c0; Contract1 c1; Contract2 c2; Contract3 c3; function setUp() public { c0 = new Contract0(); c1 = new Contract1(); c2 = new Contract2(); c3 = new Contract3(); } function testGas() public view { uint256[] memory arr = new uint256[](10); c0.nonCachedMemoryListLength(arr); c1.cachedMemoryListLength(arr); c2.nonCachedStorageListLength(); c3.cachedStorageListLength(); } } contract Contract0 { function nonCachedMemoryListLength(uint256[] memory arr) public pure { uint256 j; for (uint256 i; i < arr.length; i++) { j = arr[i] + 10; } } } contract Contract1 { function cachedMemoryListLength(uint256[] memory arr) public pure { uint256 j; uint256 length = arr.length; for (uint256 i; i < length; i++) { j = arr[i] + 10; } } } contract Contract2 { uint256[] arr = new uint256[](10); function nonCachedStorageListLength() public view { uint256 j; for (uint256 i; i < arr.length; i++) { j = arr[i] + 10; } } } contract Contract3 { uint256[] arr = new uint256[](10); function cachedStorageListLength() public view { uint256 j; uint256 length = arr.length; for (uint256 i; i < length; i++) { j = arr[i] + 10; } } }
╭───────────────────────────────────────────┬─────────────────┬──────┬────────┬──────┬─────────╮ │ src/test/GasTest.t.sol:Contract0 contract ┆ ┆ ┆ ┆ ┆ │ ╞═══════════════════════════════════════════╪═════════════════╪══════╪════════╪══════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 128171 ┆ 672 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ nonCachedMemoryListLength ┆ 3755 ┆ 3755 ┆ 3755 ┆ 3755 ┆ 1 │ ╰───────────────────────────────────────────┴─────────────────┴──────┴────────┴──────┴─────────╯ ╭───────────────────────────────────────────┬─────────────────┬──────┬────────┬──────┬─────────╮ │ src/test/GasTest.t.sol:Contract1 contract ┆ ┆ ┆ ┆ ┆ │ ╞═══════════════════════════════════════════╪═════════════════╪══════╪════════╪══════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 128777 ┆ 675 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ cachedMemoryListLength ┆ 3733 ┆ 3733 ┆ 3733 ┆ 3733 ┆ 1 │ ╰───────────────────────────────────────────┴─────────────────┴──────┴────────┴──────┴─────────╯ ╭───────────────────────────────────────────┬─────────────────┬───────┬────────┬───────┬─────────╮ │ src/test/GasTest.t.sol:Contract2 contract ┆ ┆ ┆ ┆ ┆ │ ╞═══════════════════════════════════════════╪═════════════════╪═══════╪════════╪═══════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 118474 ┆ 539 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ nonCachedStorageListLength ┆ 27979 ┆ 27979 ┆ 27979 ┆ 27979 ┆ 1 │ ╰───────────────────────────────────────────┴─────────────────┴───────┴────────┴───────┴─────────╯ ╭───────────────────────────────────────────┬─────────────────┬───────┬────────┬───────┬─────────╮ │ src/test/GasTest.t.sol:Contract3 contract ┆ ┆ ┆ ┆ ┆ │ ╞═══════════════════════════════════════════╪═════════════════╪═══════╪════════╪═══════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 118674 ┆ 540 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ cachedStorageListLength ┆ 26984 ┆ 26984 ┆ 26984 ┆ 26984 ┆ 1 │ ╰───────────────────────────────────────────┴─────────────────┴───────┴────────┴───────┴─────────╯
You can mark public or external functions as payable to save gas. Functions that are not payable have additional logic to check if there was a value sent with a call, however, making a function payable eliminates this check. This optimization should be carefully considered due to potentially unwanted behavior when a function does not need to accept ether.
contract GasTest is DSTest { Contract0 c0; Contract1 c1; function setUp() public { c0 = new Contract0(); c1 = new Contract1(); } function testGas() public { c0.isNotPayable(); c1.isPayable(); } } contract Contract0 { function isNotPayable() public view { uint256 val = 0; val++; } } contract Contract1 { function isPayable() public payable { uint256 val = 0; val++; } }
╭────────────────────┬─────────────────┬─────┬────────┬─────┬─────────╮ │ Contract0 contract ┆ ┆ ┆ ┆ ┆ │ ╞════════════════════╪═════════════════╪═════╪════════╪═════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 32081 ┆ 190 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ isNotPayable ┆ 198 ┆ 198 ┆ 198 ┆ 198 ┆ 1 │ ╰────────────────────┴─────────────────┴─────┴────────┴─────┴─────────╯ ╭────────────────────┬─────────────────┬─────┬────────┬─────┬─────────╮ │ Contract1 contract ┆ ┆ ┆ ┆ ┆ │ ╞════════════════════╪═════════════════╪═════╪════════╪═════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 29681 ┆ 178 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ isPayable ┆ 174 ┆ 174 ┆ 174 ┆ 174 ┆ 1 │ ╰────────────────────┴─────────────────┴─────┴────────┴─────┴─────────╯
You can safe gas by breaking up a require statement with multiple conditions, into multiple require statements with a single condition.
contract GasTest is DSTest { Contract0 c0; Contract1 c1; function setUp() public { c0 = new Contract0(); c1 = new Contract1(); } function testGas() public { c0.singleRequire(3); c1.multipleRequire(3); } } contract Contract0 { function singleRequire(uint256 num) public { require(num > 1 && num < 10 && num == 3); } } contract Contract1 { function multipleRequire(uint256 num) public { require(num > 1); require(num < 10); require(num == 3); } }
╭────────────────────┬─────────────────┬─────┬────────┬─────┬─────────╮ │ Contract0 contract ┆ ┆ ┆ ┆ ┆ │ ╞════════════════════╪═════════════════╪═════╪════════╪═════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 35487 ┆ 208 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ singleRequire ┆ 286 ┆ 286 ┆ 286 ┆ 286 ┆ 1 │ ╰────────────────────┴─────────────────┴─────┴────────┴─────┴─────────╯ ╭────────────────────┬─────────────────┬─────┬────────┬─────┬─────────╮ │ Contract1 contract ┆ ┆ ┆ ┆ ┆ │ ╞════════════════════╪═════════════════╪═════╪════════╪═════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 35887 ┆ 210 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ multipleRequire ┆ 270 ┆ 270 ┆ 270 ┆ 270 ┆ 1 │ ╰────────────────────┴─────────────────┴─────┴────────┴─────┴─────────╯
When comparing integers, it is cheaper to use strict >
& <
operators over >=
& <=
operators, even if you must increment or decrement one of the operands. Note: before using this technique, it's important to consider whether incrementing/decrementing one of the operators could result in an over/underflow.
This optimization is applicable when the optimizer is turned off.
contract GasTest is DSTest { Contract0 c0; Contract1 c1; Contract2 c2; Contract3 c3; function setUp() public { c0 = new Contract0(); c1 = new Contract1(); c2 = new Contract2(); c3 = new Contract3(); } function testGas() public view { c0.gte(); c1.gtPlusMinusOne(); c2.lte(); c3.ltPlusOne(); } } contract Contract0 { function gte() external pure returns (bool) { return 2 >= 2; } } contract Contract1 { function gtPlusMinusOne() external pure returns (bool) { return 2 > 2 - 1; } } contract Contract2 { function lte() external pure returns (bool) { return 2 <= 2; } } contract Contract3 { function ltPlusOne() external pure returns (bool) { return 2 < 2 + 1; } }
╭───────────────────────────────────────────┬─────────────────┬─────┬────────┬─────┬─────────╮ │ src/test/GasTest.t.sol:Contract0 contract ┆ ┆ ┆ ┆ ┆ │ ╞═══════════════════════════════════════════╪═════════════════╪═════╪════════╪═════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 37487 ┆ 218 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ gte ┆ 330 ┆ 330 ┆ 330 ┆ 330 ┆ 1 │ ╰───────────────────────────────────────────┴─────────────────┴─────┴────────┴─────┴─────────╯ ╭───────────────────────────────────────────┬─────────────────┬─────┬────────┬─────┬─────────╮ │ src/test/GasTest.t.sol:Contract1 contract ┆ ┆ ┆ ┆ ┆ │ ╞═══════════════════════════════════════════╪═════════════════╪═════╪════════╪═════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 37487 ┆ 218 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ gtPlusMinusOne ┆ 327 ┆ 327 ┆ 327 ┆ 327 ┆ 1 │ ╰───────────────────────────────────────────┴─────────────────┴─────┴────────┴─────┴─────────╯ ╭───────────────────────────────────────────┬─────────────────┬─────┬────────┬─────┬─────────╮ │ src/test/GasTest.t.sol:Contract2 contract ┆ ┆ ┆ ┆ ┆ │ ╞═══════════════════════════════════════════╪═════════════════╪═════╪════════╪═════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 37487 ┆ 218 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ lte ┆ 330 ┆ 330 ┆ 330 ┆ 330 ┆ 1 │ ╰───────────────────────────────────────────┴─────────────────┴─────┴────────┴─────┴─────────╯ ╭───────────────────────────────────────────┬─────────────────┬─────┬────────┬─────┬─────────╮ │ src/test/GasTest.t.sol:Contract3 contract ┆ ┆ ┆ ┆ ┆ │ ╞═══════════════════════════════════════════╪═════════════════╪═════╪════════╪═════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 37487 ┆ 218 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ ltPlusOne ┆ 327 ┆ 327 ┆ 327 ┆ 327 ┆ 1 │ ╰───────────────────────────────────────────┴─────────────────┴─────┴────────┴─────┴─────────╯
Consider using assembly for math instead of Solidity. You can check for overflow/underflow in assembly to ensure safety. If using Solidity versions < 0.8.0 and you are using Safemath, you can gain significant gas savings by using assembly to calculate values and checking for overflow/underflow.
contract GasTest is DSTest { Contract0 c0; Contract1 c1; Contract2 c2; Contract3 c3; Contract4 c4; Contract5 c5; Contract6 c6; Contract7 c7; function setUp() public { c0 = new Contract0(); c1 = new Contract1(); c2 = new Contract2(); c3 = new Contract3(); c4 = new Contract4(); c5 = new Contract5(); c6 = new Contract6(); c7 = new Contract7(); } function testGas() public { c0.addTest(34598345, 100); c1.addAssemblyTest(34598345, 100); c2.subTest(34598345, 100); c3.subAssemblyTest(34598345, 100); c4.mulTest(34598345, 100); c5.mulAssemblyTest(34598345, 100); c6.divTest(34598345, 100); c7.divAssemblyTest(34598345, 100); } } contract Contract0 { //addition in Solidity function addTest(uint256 a, uint256 b) public pure { uint256 c = a + b; } } contract Contract1 { //addition in assembly function addAssemblyTest(uint256 a, uint256 b) public pure { assembly { let c := add(a, b) if lt(c, a) { mstore(0x00, "overflow") revert(0x00, 0x20) } } } } contract Contract2 { //subtraction in Solidity function subTest(uint256 a, uint256 b) public pure { uint256 c = a - b; } } contract Contract3 { //subtraction in assembly function subAssemblyTest(uint256 a, uint256 b) public pure { assembly { let c := sub(a, b) if gt(c, a) { mstore(0x00, "underflow") revert(0x00, 0x20) } } } } contract Contract4 { //multiplication in Solidity function mulTest(uint256 a, uint256 b) public pure { uint256 c = a * b; } } contract Contract5 { //multiplication in assembly function mulAssemblyTest(uint256 a, uint256 b) public pure { assembly { let c := mul(a, b) if lt(c, a) { mstore(0x00, "overflow") revert(0x00, 0x20) } } } } contract Contract6 { //division in Solidity function divTest(uint256 a, uint256 b) public pure { uint256 c = a * b; } } contract Contract7 { //division in assembly function divAssemblyTest(uint256 a, uint256 b) public pure { assembly { let c := div(a, b) if gt(c, a) { mstore(0x00, "underflow") revert(0x00, 0x20) } } } }
╭────────────────────┬─────────────────┬─────┬────────┬─────┬─────────╮ │ Contract0 contract ┆ ┆ ┆ ┆ ┆ │ ╞════════════════════╪═════════════════╪═════╪════════╪═════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 40493 ┆ 233 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ addTest ┆ 303 ┆ 303 ┆ 303 ┆ 303 ┆ 1 │ ╰────────────────────┴─────────────────┴─────┴────────┴─────┴─────────╯ ╭────────────────────┬─────────────────┬─────┬────────┬─────┬─────────╮ │ Contract1 contract ┆ ┆ ┆ ┆ ┆ │ ╞════════════════════╪═════════════════╪═════╪════════╪═════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 37087 ┆ 216 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ addAssemblyTest ┆ 263 ┆ 263 ┆ 263 ┆ 263 ┆ 1 │ ╰────────────────────┴─────────────────┴─────┴────────┴─────┴─────────╯ ╭────────────────────┬─────────────────┬─────┬────────┬─────┬─────────╮ │ Contract2 contract ┆ ┆ ┆ ┆ ┆ │ ╞════════════════════╪═════════════════╪═════╪════════╪═════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 40293 ┆ 232 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ subTest ┆ 300 ┆ 300 ┆ 300 ┆ 300 ┆ 1 │ ╰────────────────────┴─────────────────┴─────┴────────┴─────┴─────────╯ ╭────────────────────┬─────────────────┬─────┬────────┬─────┬─────────╮ │ Contract3 contract ┆ ┆ ┆ ┆ ┆ │ ╞════════════════════╪═════════════════╪═════╪════════╪═════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 37287 ┆ 217 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ subAssemblyTest ┆ 263 ┆ 263 ┆ 263 ┆ 263 ┆ 1 │ ╰────────────────────┴─────────────────┴─────┴────────┴─────┴─────────╯ ╭────────────────────┬─────────────────┬─────┬────────┬─────┬─────────╮ │ Contract4 contract ┆ ┆ ┆ ┆ ┆ │ ╞════════════════════╪═════════════════╪═════╪════════╪═════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 41893 ┆ 240 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ mulTest ┆ 325 ┆ 325 ┆ 325 ┆ 325 ┆ 1 │ ╰────────────────────┴─────────────────┴─────┴────────┴─────┴─────────╯ ╭────────────────────┬─────────────────┬─────┬────────┬─────┬─────────╮ │ Contract5 contract ┆ ┆ ┆ ┆ ┆ │ ╞════════════════════╪═════════════════╪═════╪════════╪═════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 37087 ┆ 216 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ mulAssemblyTest ┆ 265 ┆ 265 ┆ 265 ┆ 265 ┆ 1 │ ╰────────────────────┴─────────────────┴─────┴────────┴─────┴─────────╯ ╭────────────────────┬─────────────────┬─────┬────────┬─────┬─────────╮ │ Contract6 contract ┆ ┆ ┆ ┆ ┆ │ ╞════════════════════╪═════════════════╪═════╪════════╪═════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 41893 ┆ 240 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ divTest ┆ 325 ┆ 325 ┆ 325 ┆ 325 ┆ 1 │ ╰────────────────────┴─────────────────┴─────┴────────┴─────┴─────────╯ ╭────────────────────┬─────────────────┬─────┬────────┬─────┬─────────╮ │ Contract7 contract ┆ ┆ ┆ ┆ ┆ │ ╞════════════════════╪═════════════════╪═════╪════════╪═════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 37287 ┆ 217 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ divAssemblyTest ┆ 265 ┆ 265 ┆ 265 ┆ 265 ┆ 1 │ ╰────────────────────┴─────────────────┴─────┴────────┴─────┴─────────╯
contract GasTest is DSTest { Contract0 c0; Contract1 c1; function setUp() public { c0 = new Contract0(); c1 = new Contract1(); } function testGas() public view { c0.solidityHash(2309349, 2304923409); c1.assemblyHash(2309349, 2304923409); } } contract Contract0 { function solidityHash(uint256 a, uint256 b) public view { //unoptimized keccak256(abi.encodePacked(a, b)); } } contract Contract1 { function assemblyHash(uint256 a, uint256 b) public view { //optimized assembly { mstore(0x00, a) mstore(0x20, b) let hashedVal := keccak256(0x00, 0x40) } } }
╭────────────────────┬─────────────────┬─────┬────────┬─────┬─────────╮ │ Contract0 contract ┆ ┆ ┆ ┆ ┆ │ ╞════════════════════╪═════════════════╪═════╪════════╪═════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 36687 ┆ 214 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ solidityHash ┆ 313 ┆ 313 ┆ 313 ┆ 313 ┆ 1 │ ╰────────────────────┴─────────────────┴─────┴────────┴─────┴─────────╯ ╭────────────────────┬─────────────────┬─────┬────────┬─────┬─────────╮ │ Contract1 contract ┆ ┆ ┆ ┆ ┆ │ ╞════════════════════╪═════════════════╪═════╪════════╪═════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 31281 ┆ 186 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ assemblyHash ┆ 231 ┆ 231 ┆ 231 ┆ 231 ┆ 1 │ ╰────────────────────┴─────────────────┴─────┴────────┴─────┴─────────╯
calldata
instead of memory
for function arguments that do not get mutated.Mark data types as calldata
instead of memory
where possible. This makes it so that the data is not automatically loaded into memory. If the data passed into the function does not need to be changed (like updating values in an array), it can be passed in as calldata
. The one exception to this is if the argument must later be passed into another function that takes an argument that specifies memory
storage.
contract GasTest is DSTest { Contract0 c0; Contract1 c1; Contract2 c2; Contract3 c3; function setUp() public { c0 = new Contract0(); c1 = new Contract1(); c2 = new Contract2(); c3 = new Contract3(); } function testGas() public { uint256[] memory arr = new uint256[](10); c0.calldataArray(arr); c1.memoryArray(arr); bytes memory data = abi.encode("someText"); c2.calldataBytes(data); c3.memoryBytes(data); } } contract Contract0 { function calldataArray(uint256[] calldata arr) public { uint256 j; for (uint256 i; i < arr.length; i++) { j = arr[i] + 10; } } } contract Contract1 { function memoryArray(uint256[] memory arr) public { uint256 j; for (uint256 i; i < arr.length; i++) { j = arr[i] + 10; } } } contract Contract2 { function calldataBytes(bytes calldata data) public { bytes32 val; for (uint256 i; i < 10; i++) { val = keccak256(abi.encode(data, i)); } } } contract Contract3 { function memoryBytes(bytes memory data) public { bytes32 val; for (uint256 i; i < 10; i++) { val = keccak256(abi.encode(data, i)); } } }
╭───────────────────────────────────────────┬─────────────────┬──────┬────────┬──────┬─────────╮ │ src/test/GasTest.t.sol:Contract0 contract ┆ ┆ ┆ ┆ ┆ │ ╞═══════════════════════════════════════════╪═════════════════╪══════╪════════╪══════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 97947 ┆ 521 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ calldataArray ┆ 2824 ┆ 2824 ┆ 2824 ┆ 2824 ┆ 1 │ ╰───────────────────────────────────────────┴─────────────────┴──────┴────────┴──────┴─────────╯ ╭───────────────────────────────────────────┬─────────────────┬──────┬────────┬──────┬─────────╮ │ src/test/GasTest.t.sol:Contract1 contract ┆ ┆ ┆ ┆ ┆ │ ╞═══════════════════════════════════════════╪═════════════════╪══════╪════════╪══════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 128171 ┆ 672 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ memoryArray ┆ 3755 ┆ 3755 ┆ 3755 ┆ 3755 ┆ 1 │ ╰───────────────────────────────────────────┴─────────────────┴──────┴────────┴──────┴─────────╯ ╭───────────────────────────────────────────┬─────────────────┬──────┬────────┬──────┬─────────╮ │ src/test/GasTest.t.sol:Contract2 contract ┆ ┆ ┆ ┆ ┆ │ ╞═══════════════════════════════════════════╪═════════════════╪══════╪════════╪══════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 100547 ┆ 534 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ calldataBytes ┆ 4934 ┆ 4934 ┆ 4934 ┆ 4934 ┆ 1 │ ╰───────────────────────────────────────────┴─────────────────┴──────┴────────┴──────┴─────────╯ ╭───────────────────────────────────────────┬─────────────────┬──────┬────────┬──────┬─────────╮ │ src/test/GasTest.t.sol:Contract3 contract ┆ ┆ ┆ ┆ ┆ │ ╞═══════════════════════════════════════════╪═════════════════╪══════╪════════╪══════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 135183 ┆ 707 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ memoryBytes ┆ 7551 ┆ 7551 ┆ 7551 ┆ 7551 ┆ 1 │ ╰───────────────────────────────────────────┴─────────────────┴──────┴────────┴──────┴─────────╯
constant
if they never change.State variables can be declared as constant or immutable. In both cases, the variables cannot be modified after the contract has been constructed. For constant variables, the value has to be fixed at compile-time, while for immutable, it can still be assigned at construction time.
The compiler does not reserve a storage slot for these variables, and every occurrence is inlined by the respective value.
Compared to regular state variables, the gas costs of constant and immutable variables are much lower. For a constant variable, the expression assigned to it is copied to all the places where it is accessed and also re-evaluated each time. This allows for local optimizations. Immutable variables are evaluated once at construction time and their value is copied to all the places in the code where they are accessed. For these values, 32 bytes are reserved, even if they would fit in fewer bytes. Due to this, constant values can sometimes be cheaper than immutable values.
contract GasTest is DSTest { Contract0 c0; Contract1 c1; Contract2 c2; function setUp() public { c0 = new Contract0(); c1 = new Contract1(); c2 = new Contract2(); } function testGas() public view { c0.addValue(); c1.addImmutableValue(); c2.addConstantValue(); } } contract Contract0 { uint256 val; constructor() { val = 10000; } function addValue() public view { uint256 newVal = val + 1000; } } contract Contract1 { uint256 immutable val; constructor() { val = 10000; } function addImmutableValue() public view { uint256 newVal = val + 1000; } } contract Contract2 { uint256 constant val = 10; function addConstantValue() public view { uint256 newVal = val + 1000; } }
╭────────────────────┬─────────────────┬──────┬────────┬──────┬─────────╮ │ Contract0 contract ┆ ┆ ┆ ┆ ┆ │ ╞════════════════════╪═════════════════╪══════╪════════╪══════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 54593 ┆ 198 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ addValue ┆ 2302 ┆ 2302 ┆ 2302 ┆ 2302 ┆ 1 │ ╰────────────────────┴─────────────────┴──────┴────────┴──────┴─────────╯ ╭────────────────────┬─────────────────┬─────┬────────┬─────┬─────────╮ │ Contract1 contract ┆ ┆ ┆ ┆ ┆ │ ╞════════════════════╪═════════════════╪═════╪════════╪═════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 38514 ┆ 239 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ addImmutableValue ┆ 199 ┆ 199 ┆ 199 ┆ 199 ┆ 1 │ ╰────────────────────┴─────────────────┴─────┴────────┴─────┴─────────╯ ╭────────────────────┬─────────────────┬─────┬────────┬─────┬─────────╮ │ Contract2 contract ┆ ┆ ┆ ┆ ┆ │ ╞════════════════════╪═════════════════╪═════╪════════╪═════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 32287 ┆ 191 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ addConstantValue ┆ 199 ┆ 199 ┆ 199 ┆ 199 ┆ 1 │ ╰────────────────────┴─────────────────┴─────┴────────┴─────┴─────────╯
contract GasTest is DSTest { Contract0 c0; Contract1 c1; function setUp() public { c0 = new Contract0(); c1 = new Contract1(); } function testGas() public view { c0.ownerNotZero(address(this)); c1.assemblyOwnerNotZero(address(this)); } } contract Contract0 { function ownerNotZero(address _addr) public pure { require(_addr != address(0), "zero address)"); } } contract Contract1 { function assemblyOwnerNotZero(address _addr) public pure { assembly { if iszero(_addr) { mstore(0x00, "zero address") revert(0x00, 0x20) } } } }
╭────────────────────┬─────────────────┬─────┬────────┬─────┬─────────╮ │ Contract0 contract ┆ ┆ ┆ ┆ ┆ │ ╞════════════════════╪═════════════════╪═════╪════════╪═════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 61311 ┆ 338 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ ownerNotZero ┆ 258 ┆ 258 ┆ 258 ┆ 258 ┆ 1 │ ╰────────────────────┴─────────────────┴─────┴────────┴─────┴─────────╯ ╭──────────────────────┬─────────────────┬─────┬────────┬─────┬─────────╮ │ Contract1 contract ┆ ┆ ┆ ┆ ┆ │ ╞══════════════════════╪═════════════════╪═════╪════════╪═════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 44893 ┆ 255 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ assemblyOwnerNotZero ┆ 252 ┆ 252 ┆ 252 ┆ 252 ┆ 1 │ ╰──────────────────────┴─────────────────┴─────┴────────┴─────┴─────────╯
Keeping revert strings under 32-bytes prevents the string from being stored in more than one memory slot.
contract GasTest is DSTest { Contract0 c0; Contract1 c1; function setUp() public { c0 = new Contract0(); c1 = new Contract1(); } function testGas() public { try c0.callRevertExpensive() {} catch {} try c1.callRevertCheap() {} catch {} } } contract Contract0 { function callRevertExpensive() external { require(false, "long revert string over 32 bytes"); } } contract Contract1 { function callRevertCheap() external { require(false, "revert string under 32 bytes"); } }
╭─────────────────────┬─────────────────┬─────┬────────┬─────┬─────────╮ │ Contract0 contract ┆ ┆ ┆ ┆ ┆ │ ╞═════════════════════╪═════════════════╪═════╪════════╪═════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 27487 ┆ 164 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ callRevertExpensive ┆ 213 ┆ 213 ┆ 213 ┆ 213 ┆ 1 │ ╰─────────────────────┴─────────────────┴─────┴────────┴─────┴─────────╯ ╭─────────────────────┬─────────────────┬─────┬────────┬─────┬─────────╮ │ Contract1 contract ┆ ┆ ┆ ┆ ┆ │ ╞═════════════════════╪═════════════════╪═════╪════════╪═════╪═════════╡ │ Deployment Cost ┆ Deployment Size ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ 27487 ┆ 164 ┆ ┆ ┆ ┆ │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ Function Name ┆ min ┆ avg ┆ median ┆ max ┆ # calls │ ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌┼╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌┤ │ callRevertCheap ┆ 210 ┆ 210 ┆ 210 ┆ 210 ┆ 1 │ ╰─────────────────────┴─────────────────┴─────┴────────┴─────┴─────────╯
#0 - c4-judge
2023-03-09T17:52:22Z
trust1995 marked the issue as grade-c
#1 - c4-judge
2023-03-09T17:52:39Z
trust1995 marked the issue as grade-b