Hi, > > introducing new codes seems like a bad idea to me. There are many > > places that do not care about the distinction between PLUS_EXPR and > > PLUSV_EXPR, and handling both cases will complicate the code (see eg. > > the problems caused by introducing POINTER_PLUS_EXPR vs PLUS_EXPR > > distinction). Why not just use a flag to mark the operation as > > non-overflowing? > > I obviously thought about this. The issue with using a flag is > that there is no convenient place to stick it and that it makes > the distinction between the two variants less visible. Consider > the folding routines that take split trees for a start. > > IMHO using new tree-codes is much less complicated than carrying > around flags. I did consider putting flags on the tree code > itself, but that isn't going to make the changes easier either.
OK, then what about this: introduce accessor functions like tree_code get_operation_semantics (tree_code) -- returns PLUS_EXPR for PLUS_EXPR and PLUSNV_EXPR, etc. bool get_operation_overflow (tree_code) -- obvious tree_code operation_code (tree_code, bool) -- PLUS_EXPR, false -> PLUS_EXPR -- PLUS_EXPR, true -> PLUSNV_EXPR -- PLUSNV_EXPR, * -> abort etc. (possibly with more clear names), and change the code to always use them? Zdenek
