InvertIfCondVsNot.md

InvertIfCondVsNot_i.sol

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

/**
 * @title InvertIfCondVsNot
 * @author IllIllI
 */
contract InvertIfCondVsNot {
    function test(bool b) external view returns (uint256) {
        return !b ? block.number : uint256(uint160(msg.sender));
    }
}

InvertIfCondVsNot_n.sol

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

/**
 * @title InvertIfCondVsNot
 * @author IllIllI
 */
contract InvertIfCondVsNot {
    function test(bool b) external view returns (uint256) {
        return b ? uint256(uint160(msg.sender)) : block.number;
    }
}

Diff

diff --git a/InvertIfCondVsNot_i.sol b/InvertIfCondVsNot_n.sol
index 5f290bc..2af9617 100644
--- a/InvertIfCondVsNot_i.sol
+++ b/InvertIfCondVsNot_n.sol
@@ -7,7 +7,7 @@ pragma solidity ^0.8.0; // optimize 200
  */
 contract InvertIfCondVsNot {
     function test(bool b) external view returns (uint256) {
-        return !b ? block.number : uint256(uint160(msg.sender));
+        return b ? uint256(uint160(msg.sender)) : block.number;
     }
 }
 

Compiled binary

$ solc InvertIfCondVsNot_i.sol --bin --optimize --optimize-runs 200 | egrep "^60[0-9]+"
608060405234801561001057600080fd5b5060c88061001f6000396000f3fe6080604052348015600f57600080fd5b506004361060285760003560e01c806336091dff14602d575b600080fd5b603c60383660046064565b6050565b604051604791906089565b60405180910390f35b60008115605c5733605e565b435b92915050565b6000602082840312156074578081fd5b813580151581146082578182fd5b9392505050565b9081526020019056fea2646970667358221220d3c09e7858bbfd32b0a37527592c4eba6ad0417317a7020b8097814d96678bf264736f6c63430008000033

$ solc InvertIfCondVsNot_n.sol --bin --optimize --optimize-runs 200 | egrep "^60[0-9]+"
608060405234801561001057600080fd5b5060c78061001f6000396000f3fe6080604052348015600f57600080fd5b506004361060285760003560e01c806336091dff14602d575b600080fd5b603c60383660046063565b6050565b604051604791906088565b60405180910390f35b600081605b5743605d565b335b92915050565b6000602082840312156073578081fd5b813580151581146081578182fd5b9392505050565b9081526020019056fea26469706673582212203fe4322ea75d9e3d96550591874328426952bae47d304ca80f2117641eac66f564736f6c63430008000033

Opcodes

PC.Inv	Operation.Inv	Gas.Inv	PC.Not	Operation.Not	Gas.Not
112(0x70)	PUSH1(0x60) ["0x00"]	3	112(0x70)	PUSH1(0x60) ["0x00"]	3
114(0x72)	DUP2(0x81)	3	114(0x72)	DUP2(0x81)	3
115(0x73)	ISZERO(0x15)	3
116(0x74)	PUSH1(0x60) ["0x5c"]	3	115(0x73)	PUSH1(0x60) ["0x5b"]	3
118(0x76)	JUMPI(0x57)	10	117(0x75)	JUMPI(0x57)	10
			118(0x76)	NUMBER(0x43)	2
119(0x77)	CALLER(0x33)	2
120(0x78)	PUSH1(0x60) ["0x5e"]	3	119(0x77)	PUSH1(0x60) ["0x5d"]	3
122(0x7a)	JUMP(0x56)	8	121(0x79)	JUMP(0x56)	8
123(0x7b)	JUMPDEST(0x5b)@0x7b	1	122(0x7a)	JUMPDEST(0x5b)@0x7a	1
			123(0x7b)	CALLER(0x33)	2
124(0x7c)	NUMBER(0x43)	2
125(0x7d)	JUMPDEST(0x5b)@0x7d	1	124(0x7c)	JUMPDEST(0x5b)@0x7c	1
126(0x7e)	SWAP3(0x92)	3	125(0x7d)	SWAP3(0x92)	3
127(0x7f)	SWAP2(0x91)	3	126(0x7e)	SWAP2(0x91)	3
128(0x80)	POP(0x50)	2	127(0x7f)	POP(0x50)	2
129(0x81)	POP(0x50)	2	128(0x80)	POP(0x50)	2
130(0x82)	JUMP(0x56)	8	129(0x81)	JUMP(0x56)	8
	Total.Inv:	57		Total.Not:	54

The change provides a savings of 3 gas