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@IllIllI000
Last active June 24, 2023 13:48
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AbiStringsSplitCommasVsNone_c.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0; // optimize 200

/**
 * @title AbiStringsSplitCommasVsNone
 * @author IllIllI
 */
contract AbiStringsSplitCommasVsNone {
    function test() external pure returns (bytes memory) {
        return abi.encodePacked("aaa", "bbb", "ccc");
    }
}

AbiStringsSplitCommasVsNone_n.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0; // optimize 200

/**
 * @title AbiStringsSplitCommasVsNone
 * @author IllIllI
 */
contract AbiStringsSplitCommasVsNone {
    function test() external pure returns (bytes memory) {
        return abi.encodePacked("aaa" "bbb" "ccc");
    }
}

Diff

diff --git a/AbiStringsSplitCommasVsNone_c.sol b/AbiStringsSplitCommasVsNone_n.sol
index 84dd713..aad1c72 100644
--- a/AbiStringsSplitCommasVsNone_c.sol
+++ b/AbiStringsSplitCommasVsNone_n.sol
@@ -7,7 +7,7 @@ pragma solidity ^0.8.0; // optimize 200
  */
 contract AbiStringsSplitCommasVsNone {
     function test() external pure returns (bytes memory) {
-        return abi.encodePacked("aaa", "bbb", "ccc");
+        return abi.encodePacked("aaa" "bbb" "ccc");
     }
 }
 

Compiled binary

$ solc AbiStringsSplitCommasVsNone_c.sol --bin --optimize --optimize-runs 200 | egrep "^60[0-9]+"
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

$ solc AbiStringsSplitCommasVsNone_n.sol --bin --optimize --optimize-runs 200 | egrep "^60[0-9]+"
608060405234801561001057600080fd5b50610105806100206000396000f3fe6080604052348015600f57600080fd5b506004361060285760003560e01c8063f8a8fd6d14602d575b600080fd5b60336047565b604051603e9190607f565b60405180910390f35b6060604051602001605690606a565b604051602081830303815290604052905090565b6861616162626263636360b81b815260090190565b6000602080835283518082850152825b8181101560a957858101830151858201604001528201608f565b8181111560b95783604083870101525b50601f01601f191692909201604001939250505056fea26469706673582212205a00d718713a663b2d4eadfdf4406666c45000f18b8be7ec19421326ba6d423d64736f6c63430008000033

Opcodes

PC.Orig Operation.Orig Gas.Orig PC.New Operation.New Gas.New
137(0x89) JUMP(0x56) 8 137(0x89) JUMP(0x56) 8
138(0x8a) JUMPDEST(0x5b)@0x8a 1 138(0x8a) JUMPDEST(0x5b)@0x8a 1
139(0x8b) PUSH9(0x68) ["0x61","0x61",... 3
139(0x8b) PUSH3(0x62) ["0x61","0x61",... 3
143(0x8f) PUSH1(0x60) ["0xe8"] 3 149(0x95) PUSH1(0x60) ["0xb8"] 3
145(0x91) SHL(0x1b) 3 151(0x97) SHL(0x1b) 3
146(0x92) DUP2(0x81) 3 152(0x98) DUP2(0x81) 3
147(0x93) MSTORE(0x52) 3 153(0x99) MSTORE(0x52) 3
148(0x94) PUSH3(0x62) ["0x31","0x31",... 3
152(0x98) PUSH1(0x60) ["0xe9"] 3
154(0x9a) SHL(0x1b) 3
155(0x9b) PUSH1(0x60) ["0x03"] 3
157(0x9d) DUP3(0x82) 3
158(0x9e) ADD(0x1) 3
159(0x9f) MSTORE(0x52) 3
160(0xa0) PUSH3(0x62) ["0x63","0x63",... 3
164(0xa4) PUSH1(0x60) ["0xe8"] 3
166(0xa6) SHL(0x1b) 3
167(0xa7) PUSH1(0x60) ["0x06"] 3
169(0xa9) DUP3(0x82) 3
170(0xaa) ADD(0x1) 3
171(0xab) MSTORE(0x52) 3
172(0xac) PUSH1(0x60) ["0x09"] 3 154(0x9a) PUSH1(0x60) ["0x09"] 3
174(0xae) ADD(0x1) 3 156(0x9c) ADD(0x1) 3
175(0xaf) SWAP1(0x90) 3 157(0x9d) SWAP1(0x90) 3
176(0xb0) JUMP(0x56) 8 158(0x9e) JUMP(0x56) 8
Total.Orig: 83 Total.New: 41

The change provides a savings of 42 gas

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