Not since these days long past (below) have the two performed together. 

From BAM:

In this landmark festival, BAM celebrates the artists of Nonesuch Records, in honor of the influential label’s 50 years. With a shared dedication to connecting artists across genres, BAM and Nonesuch have cultivated the work of artists including Steve Reich, Philip Glass , Laurie Anderson, Kronos Quartet, Stephin Merritt, and Youssou N’Dour, among so many others.

Opening the festival on September 9, iconic artists Steve Reich and Philip Glass take the stage together for the first time in more than 30 years. Glass and Reich are joined by their respective ensembles, as well as Nico Muhly, Timo Andres, Synergy Vocals, and others for a rare three-program retrospective.

The performances continue with Nonesuch legends and new voices, including renowned jazz pianist Brad Mehldau performing solo one night, then partnering with mandolinist and vocalist Chris Thile the next. Soprano Dawn Upshaw makes her BAM recital debut performing music by George Crumb and Charles Ives, accompanied on piano by Gilbert Kalish. The formidable 20-member ensemble Alarm Will Sound take on the music of living composers associated with Nonesuch including John Adams. Senegalese singer-songwriter Youssou N’Dour returns to BAM after headlining the historic Muslim Voices: Arts & Ideas program in 2009. Rhiannon Giddens (Carolina Chocolate Drops) unveils tracks from her forthcoming album, produced by T Bone Burnett. Devendra Banhart, Stephin Merritt (The Magnetic Fields), and Iron and Wine headline a triple bill full of funk, folk-rock, pop, and everything in between. And in true Nonesuch fashion, Natalie Merchant, Rhiannon Giddens, Sam Amidon, and Olivia Chaney pair up with Kronos Quartet to create entirely new arrangements from the American folk songbook. Kronos extends its stay for the first-ever collaboration with Laurie Anderson on Landfall. Continuing the theme of artist connections, Malian artists Rokia Traoré, Toumani Diabaté, and Sidiki Diabaté unite for an evening of multi-instrumental brilliance. The legendary Brazilian singer-songwriter Caetano Veloso performs a range of songs from his new release Abraçaço. Recent Nonesuch addition and Led Zeppelin alum Robert Plant closes the series with his band, The Sensational Space Shifters.