Extended

    pub const Extended = enum(u16) {
        /// A struct type definition. Contains references to ZIR instructions for
        /// the field types, defaults, and alignments.
        /// `operand` is payload index to `StructDecl`.
        /// `small` is `StructDecl.Small`.
        struct_decl,
        /// An enum type definition. Contains references to ZIR instructions for
        /// the field value expressions and optional type tag expression.
        /// `operand` is payload index to `EnumDecl`.
        /// `small` is `EnumDecl.Small`.
        enum_decl,
        /// A union type definition. Contains references to ZIR instructions for
        /// the field types and optional type tag expression.
        /// `operand` is payload index to `UnionDecl`.
        /// `small` is `UnionDecl.Small`.
        union_decl,
        /// An opaque type definition. Contains references to decls and captures.
        /// `operand` is payload index to `OpaqueDecl`.
        /// `small` is `OpaqueDecl.Small`.
        opaque_decl,
        /// A tuple type. Note that tuples are not namespace/container types.
        /// `operand` is payload index to `TupleDecl`.
        /// `small` is `fields_len: u16`.
        tuple_decl,
        /// Implements the `@This` builtin.
        /// `operand` is `src_node: Ast.Node.Offset`.
        this,
        /// Implements the `@returnAddress` builtin.
        /// `operand` is `src_node: Ast.Node.Offset`.
        ret_addr,
        /// Implements the `@src` builtin.
        /// `operand` is payload index to `LineColumn`.
        builtin_src,
        /// Implements the `@errorReturnTrace` builtin.
        /// `operand` is `src_node: Ast.Node.Offset`.
        error_return_trace,
        /// Implements the `@frame` builtin.
        /// `operand` is `src_node: Ast.Node.Offset`.
        frame,
        /// Implements the `@frameAddress` builtin.
        /// `operand` is `src_node: Ast.Node.Offset`.
        frame_address,
        /// Same as `alloc` from `Tag` but may contain an alignment instruction.
        /// `operand` is payload index to `AllocExtended`.
        /// `small`:
        ///  * 0b000X - has type
        ///  * 0b00X0 - has alignment
        ///  * 0b0X00 - 1=const, 0=var
        ///  * 0bX000 - is comptime
        alloc,
        /// The `@extern` builtin.
        /// `operand` is payload index to `BinNode`.
        builtin_extern,
        /// Inline assembly.
        /// `operand` is payload index to `Asm`.
        @"asm",
        /// Same as `asm` except the assembly template is not a string literal but a comptime
        /// expression.
        /// The `asm_source` field of the Asm is not a null-terminated string
        /// but instead a Ref.
        asm_expr,
        /// Log compile time variables and emit an error message.
        /// `operand` is payload index to `NodeMultiOp`.
        /// `small` is `operands_len`.
        /// The AST node is the compile log builtin call.
        compile_log,
        /// The builtin `@TypeOf` which returns the type after Peer Type Resolution
        /// of one or more params.
        /// `operand` is payload index to `TypeOfPeer`.
        /// `small` is `operands_len`.
        /// The AST node is the builtin call.
        typeof_peer,
        /// Implements the `@min` builtin for more than 2 args.
        /// `operand` is payload index to `NodeMultiOp`.
        /// `small` is `operands_len`.
        /// The AST node is the builtin call.
        min_multi,
        /// Implements the `@max` builtin for more than 2 args.
        /// `operand` is payload index to `NodeMultiOp`.
        /// `small` is `operands_len`.
        /// The AST node is the builtin call.
        max_multi,
        /// Implements the `@addWithOverflow` builtin.
        /// `operand` is payload index to `BinNode`.
        /// `small` is unused.
        add_with_overflow,
        /// Implements the `@subWithOverflow` builtin.
        /// `operand` is payload index to `BinNode`.
        /// `small` is unused.
        sub_with_overflow,
        /// Implements the `@mulWithOverflow` builtin.
        /// `operand` is payload index to `BinNode`.
        /// `small` is unused.
        mul_with_overflow,
        /// Implements the `@shlWithOverflow` builtin.
        /// `operand` is payload index to `BinNode`.
        /// `small` is unused.
        shl_with_overflow,
        /// `@round`, `@floor`, `@ceil`, or `@trunc`, with a result type.
        /// `operand` is payload index to `BinNode`.
        /// `small` is a `RoundOp` representing the specific operation being performed.
        round_op,
        /// Returns the type for the operand of a rounding op.
        /// `operand` is `UnNode`.
        /// `small` is unused.
        round_op_ty,
        /// `operand` is payload index to `UnNode`.
        wasm_memory_size,
        /// `operand` is payload index to `BinNode`.
        wasm_memory_grow,
        /// The `@prefetch` builtin.
        /// `operand` is payload index to `BinNode`.
        prefetch,
        /// Implement builtin `@setFloatMode`.
        /// `operand` is payload index to `UnNode`.
        set_float_mode,
        /// Implements the `@errorCast` builtin.
        /// `operand` is payload index to `BinNode`. `lhs` is dest type, `rhs` is operand.
        error_cast,
        /// Implements `@breakpoint`.
        /// `operand` is `src_node: Ast.Node.Offset`.
        breakpoint,
        /// Implement builtin `@disableInstrumentation`. `operand` is `src_node: Ast.Node.Offset`.
        disable_instrumentation,
        /// Implement builtin `@disableIntrinsics`. `operand` is `src_node: i32`.
        disable_intrinsics,
        /// Implements the `@select` builtin.
        /// `operand` is payload index to `Select`.
        select,
        /// Implement builtin `@errToInt`.
        /// `operand` is payload index to `UnNode`.
        int_from_error,
        /// Implement builtin `@errorFromInt`.
        /// `operand` is payload index to `UnNode`.
        error_from_int,
        /// Given a comptime-known operand of type `[]const A`, returns the type `*const [operand.len]B`.
        /// The types `A` and `B` are determined from `ReifySliceArgInfo`.
        /// This instruction is used to provide result types to arguments of `@Fn`, `@Struct`, etc.
        /// `operand` is payload index to `UnNode`.
        /// `small` is a bitcast `ReifySliceArgInfo`.
        reify_slice_arg_ty,
        /// Like `reify_slice_arg_ty` for the specific case of `[]const []const u8` to `[]const TagInt`,
        /// as needed for `@Enum`.
        /// `operand` is payload index to `BinNode`. lhs is the type `TagInt`. rhs is the `[]const []const u8` value.
        /// `small` is unused.
        reify_enum_value_slice_ty,
        /// Given a comptime-known operand of type `type`, returns the type `?operand` if possible, otherwise `?noreturn`.
        /// Used for the final arg of `@Pointer` to allow reifying pointers to opaque types.
        /// `operand` is payload index to `UnNode`.
        /// `small` is unused.
        reify_pointer_sentinel_ty,
        /// Implements builtin `@Tuple`.
        /// `operand` is payload index to `UnNode`.
        reify_tuple,
        /// Implements builtin `@Pointer`.
        /// `operand` is payload index to `ReifyPointer`.
        reify_pointer,
        /// Implements builtin `@Fn`.
        /// `operand` is payload index to `ReifyFn`.
        reify_fn,
        /// Implements builtin `@Struct`.
        /// `operand` is payload index to `ReifyStruct`.
        /// `small` contains `NameStrategy`.
        reify_struct,
        /// Implements builtin `@Union`.
        /// `operand` is payload index to `ReifyUnion`.
        /// `small` contains `NameStrategy`.
        reify_union,
        /// Implements builtin `@Enum`.
        /// `operand` is payload index to `ReifyEnum`.
        /// `small` contains `NameStrategy`.
        reify_enum,
        /// Implements builtin `@SpirvType`.
        /// `operand` is payload index to `ReifyFn`.
        reify_spirv_type,
        /// Implements the `@cmpxchgStrong` and `@cmpxchgWeak` builtins.
        /// `small` 0=>weak 1=>strong
        /// `operand` is payload index to `Cmpxchg`.
        cmpxchg,
        /// Implement builtin `@cVaArg`.
        /// `operand` is payload index to `BinNode`.
        c_va_arg,
        /// Implement builtin `@cVaCopy`.
        /// `operand` is payload index to `UnNode`.
        c_va_copy,
        /// Implement builtin `@cVaEnd`.
        /// `operand` is payload index to `UnNode`.
        c_va_end,
        /// Implement builtin `@cVaStart`.
        /// `operand` is `src_node: Ast.Node.Offset`.
        c_va_start,
        /// Implements the following builtins:
        /// `@ptrCast`, `@alignCast`, `@addrSpaceCast`, `@constCast`, `@volatileCast`.
        /// Represents an arbitrary nesting of the above builtins. Such a nesting is treated as a
        /// single operation which can modify multiple components of a pointer type.
        /// `operand` is payload index to `BinNode`.
        /// `small` contains `FullPtrCastFlags`.
        /// AST node is the root of the nested casts.
        /// `lhs` is dest type, `rhs` is operand.
        ptr_cast_full,
        /// `operand` is payload index to `UnNode`.
        /// `small` contains `FullPtrCastFlags`.
        /// Guaranteed to only have flags where no explicit destination type is
        /// required (const_cast and volatile_cast).
        /// AST node is the root of the nested casts.
        ptr_cast_no_dest,
        /// Implements the `@workItemId` builtin.
        /// `operand` is payload index to `UnNode`.
        work_item_id,
        /// Implements the `@workGroupSize` builtin.
        /// `operand` is payload index to `UnNode`.
        work_group_size,
        /// Implements the `@workGroupId` builtin.
        /// `operand` is payload index to `UnNode`.
        work_group_id,
        /// Implements the `@inComptime` builtin.
        /// `operand` is `src_node: Ast.Node.Offset`.
        in_comptime,
        /// Restores the error return index to its last saved state in a given
        /// block. If the block is `.none`, restores to the state from the point
        /// of function entry. If the operand is not `.none`, the restore is
        /// conditional on the operand value not being an error.
        /// `operand` is payload index to `RestoreErrRetIndex`.
        /// `small` is undefined.
        restore_err_ret_index,
        /// Retrieves a value from the current type declaration scope's closure.
        /// `operand` is `src_node: Ast.Node.Offset`.
        /// `small` is closure index.
        closure_get,
        /// Used as a placeholder instruction which is just a dummy index for Sema to replace
        /// with a specific value. For instance, this is used for the capture of an `errdefer`.
        /// This should never appear in a body.
        value_placeholder,
        /// Implements the `@fieldParentPtr` builtin.
        /// `operand` is payload index to `FieldParentPtr`.
        /// `small` contains `FullPtrCastFlags`.
        /// Guaranteed to not have the `ptr_cast` flag.
        /// Uses the `pl_node` union field with payload `FieldParentPtr`.
        field_parent_ptr,
        /// Get a type or value from `std.lang`.
        /// `operand` is `src_node: Ast.Node.Offset`.
        /// `small` is an `Inst.StdLangValue`.
        std_lang_value,
        /// Provide a `@branchHint` for the current block.
        /// `operand` is payload index to `UnNode`.
        /// `small` is unused.
        branch_hint,
        /// Compute the result type for in-place arithmetic, e.g. `+=`.
        /// `operand` is `Zir.Inst.Ref` of the loaded LHS (*not* its type).
        /// `small` is an `Inst.InplaceOp`.
        inplace_arith_result_ty,
        /// Marks a statement that can be stepped to but produces no code.
        /// `operand` and `small` are ignored.
        dbg_empty_stmt,
        /// At this point, AstGen encountered a fatal error which terminated ZIR lowering for this body.
        /// A file-level error has been reported. Sema should terminate semantic analysis.
        /// `operand` and `small` are ignored.
        /// This instruction is always `noreturn`, however, it is not considered as such by ZIR-level queries. This allows AstGen to assume that
        /// any code may have gone here, avoiding false-positive "unreachable code" errors.
        astgen_error,
        /// Given a type, strips away any error unions or optionals stacked
        /// on top and returns the base type. That base type must be a float.
        /// For example: Provided with `error{Foo}!?f64`, returns `f64`.
        /// `operand` is payload index to `UnNode`.
        float_op_result_ty,

        pub const InstData = struct {
            opcode: Extended,
            small: u16,
            operand: u32,
        };
    }