EGCS: pointer to member functions.
Tue Jun 22 23:14:00 GMT 1999
On Jun 22, 1999, Jason Merrill <email@example.com> wrote:
> I'm really don't think this change is a good idea; going through a thunk
> costs more than a simple test. With branch prediction, the cost of the
> test is about zero, while the thunk adds an extra jump.
But the thunk would only be used for
pointer-to-virtual-member-function. With the current code, users are
paying the price of an additional test and branch even when they only
Moreover, even if the test cost is close to zero, it would still have
to branch, and, given that the `thunk' I have in mind is as simple as
a `trampoline', I don't see how it could be less efficient than the
current approach. Only if branches with good prediction were much
cheaper than a 100% certain jump; is this the case?
Alexandre Oliva http://www.dcc.unicamp.br/~oliva IC-Unicamp, Bra[sz]il
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