fn affine_terms<'a>(relation: &Relation<'a>) -> ([Option<&'a SymExpr>; 2], U256)Expand description
Recovers equalities compiled as ISZERO(ADD(word, constant)) or ISZERO(SUB(a, b)).
Only the equality boundary admits these rewrites: addition inside an XOR remains opaque
because carries are not linear over GF(2). Every constant operation wraps at EVM word width.