br

pub fn br(self: *WipFunction, dest: Block.Index) Allocator.Error!Instruction.Index {
    try self.ensureUnusedExtraCapacity(1, NoExtra, 0);
    const instruction = try self.addInst(null, .{ .tag = .br, .data = @intFromEnum(dest) });
    dest.ptr(self).branches += 1;
    return instruction;
}