Agreed. I think my only remaining question is whether those big assembly files are ok. They contain macros, so they're clearly not plain disassemblies, and I think their size might be exaggerated by loop unrolling. Still... I can't imagine that they were hand-written, so I think we need to know more about them.
One question for DFSG: can we regard the assembly code as a form of “source code”, even if they are generated from the unknown artifact (e.g., some compiled binary objects)?
Theoretically, the assembly is fully explainable as the AMD GPU ISA manual is public [21].
Unfortunately, no. The source in question must be the "preferred form
for making modifications", so unless upstream indeed wrote these by
hand, they would not be compliant.
(There are corner cases, eg: when the original form no longer exists.)