EGCS: pointer to member functions.
Wed Jun 23 00:46:00 GMT 1999
>>>>> Alexandre Oliva <firstname.lastname@example.org> writes:
> 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
> use pointer-to-non-virtual-member-function.
If the class has virtual functions, yes.
> 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?
So I'm told. I must admit that I don't really understand the situation
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