PredictableMemoryAccessOptimizations has become unmaintainable as-is.
RedundantLoadElimination does (almost) the same thing as PredictableMemoryAccessOptimizations.
It's not as powerful but good enough because PredictableMemoryAccessOptimizations is actually only needed for promoting integer values for mandatory constant propagation.
And most importantly: RedundantLoadElimination does not insert additional copies which was a big problem in PredictableMemoryAccessOptimizations.
Fixes rdar://142814676
Having a Swift array of C++ reference types without crashing at runtime only became possible recently (https://github.com/apple/swift/pull/73615). When building against an older runtime, one would still see runtime crashes. This is expected because part of the fix is in the Swift runtime.
This makes sure we don't try to run tests for C++ reference types with an older Swift runtime.
rdar://128681137
This fixes a crash at runtime when destroying a Swift array of values of a C++ foreign reference type.
Swift optimizes the amount of metadata emitted for `_ContiguousArrayStorage<Element>` by reusing `_ContiguousArrayStorage<AnyObject>` whenever possible (see `getContiguousArrayStorageType`). However, C++ foreign reference types are not `AnyObject`s, since they have custom retain/release operations.
This change disables the `_ContiguousArrayStorage` metadata optimization for C++ reference types, which makes sure that `swift_arrayDestroy` will call the correct release operation for elements of `[MyCxxRefType]`.
rdar://127154770
Before this patch we tried to do lookup in the _ObjC module for the retain/release functions. Now we use the clang module that the reference type lives in.
