OpenCL

Clang printf

Upstreamed fix to LLVM: https://github.com/llvm/llvm-project/pull/150210

-> Merged into main branch (LLVM 22) and backported to LLVM 21

-> Branch for LLVM 20 closed, no more releases planned

PoCL 

> Sometimes statements like if (iThread == 0) printf("..."); are printed by all threads. Can be fixed with a barrier after the print. 

Bug report: https://github.com/pocl/pocl/issues/1977

Bug confirmend, but PoCL devs are rewriting their loop vectorizer. 

New loop vectorizer: Fixes this particular issue.

However, full decoder kernel runs into endless loop / deadlock with it, so can't test original issues yet.

Working on reproducer for deadlock now.