I have a handful of warmup recommendations:
Franske Piger sounds like a meeting between M83 and Thomas Helmig in a dark alley. Romantic, 80's tinged pop rock. Saw them this weekend on SPOT Festival. They're a full, five man band live, as opposed to the two dudes who record the music.
Fugleflugten ought to be a treat for those of you looking forward to Slowdive. They share some aspects, namely that spacious, reverb-laden sound.
The Love Coffin is a raw, emotional live act who play unhinged, desperate post punk. Hard to pin down, but maybe they're equal parts Jesus & Mary Chain, Gun Club and Suede, approximately? Saw them last autumn, warming up for Fright Eye and Molly. I love Molly, but The Love Coffin was a pleasantly abrasive surprise.
Modest is just a solid, honest rock band. Very young guys, but also very disciplined and extremely hardworking in a live setting. Saw them on SPOT Festival last year.
Værket play ambitious prog rock much in the vein of Jethro Tull or King Crimson. Long, labyrinthine songs, heaps of guys on stage including an waif-thin elf-like dude on transverse flute (!), a very flamboyant lead singer channelling his inner Freddie Mercury and literally the wildest drummer, I've seen in years (he also plays in the black metal band Slægt). Saw them twice last year, one of those times was at Roskilde – they played the small Mayhem/Escho stage west of Orange Stage. These are the ones you CANNOT miss.
Based on their sheer energy alone, I'm also inclined to go check out SIBIIR and Bæst at Roskilde. Gonna see Ayowa next weekend.