[SR-9466] Redo AssignInst lowering in DI

[slavapestov]

Previous ID	SR-9466
Radar	None
Original Reporter	@slavapestov
Type	Bug
Status	Resolved
Resolution	Done

Additional Detail from JIRA

Votes	0
Component/s	Compiler
Labels	Bug, SILGen, StarterBug
Assignee	@slavapestov
Priority	Medium

md5: e1c8a6fadd6a566b95dae2f52adf2edc

Issue Description:

As a follow-up to #21160 we should change DI to not do AssignInst lowering itself.

Instead, amend AssignInst with an initialization kind, either Unknown, Init, Reinit or Assign. New AssignInsts emitted by SILGen begin as Unknown. DI sets them to Init, Reinit or Assign. Then the RawSILInstructionLowering pass rewrites them as follows:

• Init becomes a StoreInst Init

• Reinit becomes a LoadInst, DeallocRefInst, and StoreInst

• Assign becomes a StoreInst Assign

[gottesmm]

If anyone wants to do this as a starter bug. I am happy to mentor.

[swift-ci]

Comment by Mani Ramezan (JIRA)

@gottesmm I would love to : )

[Azoy]

Mani (JIRA User) are you still working on this? I'd like to take a stab at this one if you don't mind.

[swift-ci]

Comment by Mani Ramezan (JIRA)

@Azoy I haven't started working on it, please feel free to assign it to yourself

[Azoy]

#21827