Warm-up Early: Weightlifting Training Mobility & Preparation
Not all of us have the luxury of a schedule that allows the following, but you may still be able to pull off something similar. One of the great things about training twice a day is that the second sessions always feels great - at least with regard to being warm and loose. Even hours later, you'll still be "warm" from that first workout.
You can get some of that benefit without doing a full workout, and potentially without even going to the gym. Try doing your warm-up in the morning even if you're going to train in the afternoon. It doesn't need to be the full meal deal, but a quick series of dynamic range of motion exercises, easy calesthenics, foam rolling, and yes - even static stretches. You can do your ab work and any pre-hab type stuff like rotator cuff exercises - Things you know you need to do, and know you tend to skip because by the time you're done with your real workout, you're too tired and uninterested to bother. This can be anything from 5-20 minutes depending on what you want to do and what you have time to squeeze in.
When you come in for your real workout later that day, still do a warm-up, but make it an abbreviated one. You may not need the foam roller, for example - a few dynamic stretches and some work with the bar may be all you need. Quick and easy, and you don't have to bother with the abs when all you want to do is drink your protein shake and go hold the couch down with your ass.
This can help with mobility in the long term by getting you moving more in a given day, and often people feel much better throughout the day even just with the littlest dose of activity in the morning. Try it out and find the formula that works best for you.