[llvm] [SandboxIR] Implement FenceInst (PR #105920)

[via llvm-commits]

================
@@ -575,6 +575,33 @@ void Instruction::dumpOS(raw_ostream &OS) const {
 }
 #endif // NDEBUG
 
+FenceInst *FenceInst::create(AtomicOrdering Ordering, BBIterator WhereIt,
+                             BasicBlock *WhereBB, Context &Ctx,
----------------
vporpo wrote:

We don't have an InsertPosition class yet. We will refactor all create() functions at some point to use that once it's available.

https://github.com/llvm/llvm-project/pull/105920