On Thursday, 23 August 2018 at 23:27:51 UTC, Walter Bright wrote:
Back to throwing constructors.
1) They are expensive, adding considerable hidden bloat in the
form of finally blocks, one for each constructing field. These
unwinding frames defeat optimization. The concept of "zero-cost
exception handling" is a bad joke. (Even Chandler Carruth
stated that the LLVM basically gives up trying to optimize in
the presence of exception handlers.) Herb Sutter has a recent
paper out proposing an alternative, completely different, error
handling scheme for C++ because of this issue.
Are you referring to http://wg21.link/P0709 ?
