GCC does this match.pd. Here's the add_zero example, I think: /* Simplifications of operations with one constant operand and simplifications to con

GCC does this match.pd. Here's the add_zero example, I think: /* Simplifications of operations with one constant operand and simplifications to constants or single values. */ (for op (plus pointer_plus minus bit_ior bit_xor) (simplify (op @0 integer_zerop) (non_lvalue @0))) https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=gcc/match.pd https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=gcc/match.pd The floating point case can be more complicated because of signed zeros and signaling NaNs, see fold_real_zero_addition_p.