On 2018-09-20 11:13:59 -0400, Jason Merrill wrote: > Indeed, whether this sort of warning is a false positive depends on > values, which the optimizers can always do better with. We could > build some logic into the front end, e.g. recognize that a & > expression will always fit in the smallest of its operand types, but
This is not true with int & signed char, where the signed char is negative. > on the other hand that duplicates things that other parts of the > compiler already deal with, so there's a question of how to share > these rules between front and middle end, like we're doing more of > with constant folding. Perhaps we could use the folder somehow. -- Vincent Lefèvre <vinc...@vinc17.net> - Web: <https://www.vinc17.net/> 100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/> Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)
