On Thu, Oct 20, 2022 at 01:44:15AM +0000, Jiang, Haochen wrote: > Maybe the testcase change cause some misunderstanding and concern. > > Actually, the patch did not disrupt the previous builtins, as the > builtin_prefetch > uses vargs. I set the default value of the new parameter as data prefetch, > which > means that if we are not using the fourth parameter, just like how we use > prefetch previously, it is still what it is.
I still think it is a mistake to have one builtin do two very distinct operations, only very superficially related. Instruction fetch and data demand loads are almosty entirely unrelated, and so is the prefetch machinery for them, on all machines I am familiar with. Which makes sense anyway, since instruction prefetch and data prefetch have completely different performance characteristics and considerations. Maybe if you start with the mistake of having unified L1 caches it seems natural, but thankfully most machines do not do that. Segher
