[SandboxIR] Implement StoreInst

[vporpo]

This patch adds the SandboxIR StoreInst instruction which mirrors llvm::StoreInst.

[vporpo]

This is basically the same patch as the previous one, but for StoreInst instead of LoadInst.

[tschuett]

I have two jokes:
A MemoryAccessBase for LoadInst and StoreInst with:

 Value *getPointerOperand() const;
  Align getAlign() const { return cast<llvm::StoreInst>(Val)->getAlign(); }
  bool isSimple() const { return cast<llvm::StoreInst>(Val)->isSimple(); }
  bool isUnordered() const { return cast<llvm::StoreInst>(Val)->isUnordered(); }

Second joke: Instructions.h to split them out of SandboxIR.h

[vporpo]

A MemoryAccessBase for LoadInst and StoreInst with:

This is very reasonable, and it would be very useful in in code that works with either Loads or Stores. The only downside that I can think of is that it deviates from the LLVM class hierarchy, which we try to avoid as we want to make this API feel like LLVM as much as possible.

Instructions.h to split them out of SandboxIR.h

This is also very reasonable, and I think we should do this at some point in a followup NFC patch.

[alinas]

LGTM.

On the first suggestion comment: deviating from the class hierarchy should be transparent to the user of the APIs. It would reduce some of the duplication, so it is worth considering to do in a follow-up NFC (i.e. both are).

[vporpo]

so it is worth considering to do in a follow-up NFC (i.e. both are).
Agreed