[llvm] [SandboxIR] Implement UnreachableInst (PR #101856)

[Julius Alexandre via llvm-commits]

================
@@ -952,6 +957,44 @@ class StoreInst final : public Instruction {
 #endif
 };
 
+class UnreachableInst final : public Instruction {
+  /// Use UnreachableInst::create() instead of calling the constructor.
+  UnreachableInst(llvm::Instruction *I, Context &Ctx)
+      : Instruction(ClassID::Unreachable, Opcode::Unreachable, I, Ctx) {}
+  UnreachableInst(ClassID SubclassID, llvm::Instruction *I, Context &Ctx)
+      : Instruction(SubclassID, Opcode::Unreachable, I, Ctx) {}
+  friend Context;
+  Use getOperandUseInternal(unsigned OpIdx, bool Verify) const final {
+    return getOperandUseDefault(OpIdx, Verify);
+  }
+  SmallVector<llvm::Instruction *, 1> getLLVMInstrs() const final {
+    return {cast<llvm::Instruction>(Val)};
+  }
+
+public:
+  static UnreachableInst *create(Instruction *InsertBefore, Context &Ctx);
+  static UnreachableInst *create(BasicBlock *InsertAtEnd, Context &Ctx);
+  static bool classof(const Value *From);
+  unsigned getNumSuccessors() const { return 0; }
+  BasicBlock *getSuccessor(unsigned idx) const {
----------------
medievalghoul wrote:

done.

https://github.com/llvm/llvm-project/pull/101856