[llvm] [SandboxIR] Implement UnaryInstruction class (PR #101541)

[Arthur Eubanks via llvm-commits]

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@@ -836,10 +839,26 @@ class BranchInst : public Instruction {
 #endif
 };
 
-class LoadInst final : public Instruction {
+/// An abstract class, parent of unary instructions.
+class UnaryInstruction : public Instruction {
+protected:
+  UnaryInstruction(ClassID ID, Opcode Opc, llvm::Instruction *LLVMI,
+                   Context &Ctx)
+      : Instruction(ID, Opc, LLVMI, Ctx) {}
+
+public:
+  static bool classof(const Instruction *I) {
+    return I->getOpcode() == Instruction::Opcode::Load || isa<CastInst>(I);
+  }
+  static bool classof(const Value *V) {
+    return isa<Instruction>(V) && classof(cast<Instruction>(V));
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aeubanks wrote:

although I like the less redundant dyn_cast version, there is merit to keeping code short. I would bring this up on discourse if you feel strongly about this

https://github.com/llvm/llvm-project/pull/101541