It occured to me that one way to associate a cost with an alternative is to attach the cost to the constraint itself; and to avoid introducing yet another syntax, the cost modifier could be an attribute of the define_constraint (in case of overloaded constraints, it should be on the definition which defines the variant which drives reload in this instance). The attribute definition would go at the end of the constraint definition like it does for insn patterns. So if somebody has another requirement of constraint modification - e.g. to avoid sprinkling the md file with '#' and '*', and to overcome their limitations WRT multi-character constraint - this could be easily added with the same syntax. `
