[llvm] [SandboxIR][NFC] SingleLLVMInstructionImpl class (PR #102687)

[Jorge Gorbe Moya via llvm-commits]

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@@ -713,27 +713,43 @@ class Instruction : public sandboxir::User {
 #endif
 };
 
-class SelectInst : public Instruction {
-  /// Use Context::createSelectInst(). Don't call the
-  /// constructor directly.
-  SelectInst(llvm::SelectInst *CI, Context &Ctx)
-      : Instruction(ClassID::Select, Opcode::Select, CI, Ctx) {}
-  friend Context; // for SelectInst()
+/// Instructions that contain a single LLVM Instruction can inherit from this.
+class SingleLLVMInstructionImpl : public Instruction {
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slackito wrote:

It would be nice if we could go a little further and have `verify()` and `dump()` here as well to remove some more repetition.

The cast in `verify` should be doable using CRTP, but I don't have any good idea for the `"Expected SomeInst"` message that doesn't involve macros and operand stringification, which is a bit ugly.

https://github.com/llvm/llvm-project/pull/102687