[llvm] [DebugInfo][LoopVectorizer][NFC] Use unknown annotations for more instructions (PR #170522)

[Ramkumar Ramachandra via llvm-commits]

artagnon wrote:

> We use compiler generated annotations for instructions that are generated by the compiler but don't correspond to user code; there are some examples in global variable opt, loop unswitching, and tail recursion elimination right now, and also Clang applies it to any instructions it generates that weren't assigned a source location

Thanks for the explanation, and examples! You're right that VPlan is somewhat special, and the compiler-generated annotations might not work, since it's not exactly IR, but rather a separate overlay on the IR. We have to think about how to get accurate DebugLocs in VPlan some more.

https://github.com/llvm/llvm-project/pull/170522