[fsckboy]

the context here doesn't actually specify whether we are talking about companies using llvm sources to create proprietary compilers (or maybe integrated with a proprietary IDE) or using llvm to quickly bootstrap and craft a compiler for a new processor, new language, etc., where they will distribute the source to the compiler anyway

but such a compiler or IDE would not GPLv3 infect it's users' target sources and binaries.

[int_19h]

The main problem with GPLv3 specifically from the perspective of various commercial vendors is the patent clause.