Hi Brian,
Sorry about the missing tarball. I could not upload such a large file to github. I am trying to find an easy way to build this compiler using github . Using svn to the gcc hsa branch is painful way to build it. Also, the gcc hsa team is moving to HSA1.0F. There will be a lot of changes for this. I will upload new instructions later this week. You are not missing much because this compiler is very experimental. A better compiler is in the works.
Greg