Depends On D104999
Automatic reference counting based on the liveness analysis can add a lot of reference counting overhead at runtime. If the IR is known to be constrained to few particular "shapes", it's much more efficient to provide a custom reference counting policy that will specify where it is required to update the async value reference count.
Reviewed By: mehdi_amini
Differential Revision: https://reviews.llvm.org/D105037
Support reference counted values implicitly passed (live) only to some of the successors.
Example: if branched to ^bb2 token will leak, unless `drop_ref` operation is properly created
```
^entry:
%token = async.runtime.create : !async.token
cond_br %cond, ^bb1, ^bb2
^bb1:
async.runtime.await %token
async.runtime.drop_ref %token
br ^bb2
^bb2:
return
```
Reviewed By: mehdi_amini
Differential Revision: https://reviews.llvm.org/D103102
Depends On D95311
Previous automatic-ref-counting pass worked with high level async operations (e.g. async.execute), however async values reference counting is a runtime implementation detail.
New pass mostly relies on the save liveness analysis to place drop_ref operations, and does better verification of CFG with different liveIn sets in block successors.
This is almost NFC change. No new reference counting ideas, just a cleanup of the previous version.
Reviewed By: mehdi_amini
Differential Revision: https://reviews.llvm.org/D95390
Eugene Zhulenev