yul-prefer-iszero

Recommends using iszero instead of eq when comparing to the 0 literal in Yul code.

iszero is more readable, uses less gas, and results in smaller bytecode.

Rule details

Examples of incorrect code for this rule:

contract A {
  function f(uint a) public {
    uint x;

    assembly {
      x := eq(a, 0)
      x := eq(0, a)
    }
  }
}

Examples of correct code for this rule:

contract A {
  function f(uint a) public {
    uint x;

    assembly {
      x := iszero(a)
    }
  }
}