Just put out avr-gcc.senthilthecoder.com - an interactive environment that lets you see code generated from a bunch of Atmel compilers and FSF trunk.
I ran into Matt Godbolt's compiler explorer a while back, and wanted something like that for avr - the version he provides is ancient. I tried something similar before - but his was way better. In particular, the option to view code generated by different toolchain versions side by side, with color coding for source line mapping, was irresistible.
He's graciously put the source for the website out on github, so I took that, tweaked it a bit, downloaded and plugged in a few Atmel toolchains, setup a cron job to build and plugin FSF trunk, and hosted it on my VPS. Was planning to build and plugin gcc-5 and gcc-6 for avr too, but disk space is tight.
Hope you guys like it