Extended Description

Clang 12.x adds must progress to loops/functions in C++11 and later and to some loops in C11 and later, which in turn enables more aggressive loop deletion.

Some code-bases may not be ready for this behavior and recently we added -ffinite-loops/-fno-finite-loops to Clang, to allow the user to disable the new behavior.

It would be good to pick this to the 12.x release branch.

Unfortunately the patches do not apply cleanly on 12.x

I resolved the conflicts and put up https://reviews.llvm.org/D96850