What Is the Performance Impact of the Compiler’s Built-in Checks?

The performance impact of the compiler's built-in checks is a slight, but measurable, increase in gas cost compared to completely unchecked arithmetic in older Solidity versions. The compiler inserts opcodes to perform the necessary checks before and after each arithmetic operation.

However, this overhead is considered a necessary and small price for the massive security gain, as it eliminates an entire class of catastrophic financial vulnerabilities by default.