rjmccall added inline comments.
================
Comment at: clang/lib/Sema/SemaOverload.cpp:9481
+ // emitted, Cand1 is not better than Cand2. This rule should have precedence
+ // over other rules.
+ //
----------------
Please add `[CUDA]` or something similar to the top of this comment so that
readers can immediately know that it's dialect-specific.
At a high level, this part of the rule is essentially saying that CUDA
non-emittability is a kind of non-viability. Should we just make non-emittable
functions get flagged as non-viable (which will avoid a lot of relatively
expensive conversion checking), or is it important to be able to select
non-emittable candidates over candidates that are non-viable for other reasons?
================
Comment at: clang/lib/Sema/SemaOverload.cpp:9749
+ if (isBetterMultiversionCandidate(Cand1, Cand2))
+ return true;
+
----------------
If we move anything below this check, it needs to figure out a tri-state so
that it can return false if `Cand2` is a better candidate than `Cand1`. Now,
that only matters if multiversion functions are supported under CUDA, but if
you're relying on them not being supported, that should at least be commented
on.
================
Comment at: clang/lib/Sema/SemaOverload.cpp:9752
+ // If other rules cannot determine which is better, CUDA preference is used
+ // to determine which is better.
+ if (S.getLangOpts().CUDA && Cand1.Function && Cand2.Function) {
----------------
Okay, let's think about the right place to put this check in the ordering; we
don't want different extensions to get into a who-comes-last competition.
- Certainly this should have lower priority than the standard-defined
preferences like argument conversion ranks or `enable_if` partial-ordering.
- The preference for pass-object-size parameters is probably most similar to a
type-based-overloading decision and so should take priority.
- I would say that this should take priority over function multi-versioning.
Function multi-versioning is all about making specialized versions of the "same
function", whereas I think host/device overloading is meant to be semantically
broader than that.
What do you think?
Regardless, the rationale for the order should be explained in comments.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D77954/new/
https://reviews.llvm.org/D77954
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
