[PATCH] D46815: [DbgInfo] Fix StripDebugInfo

[Vedant Kumar via llvm-commits]

If you have spare cycles, could you try to take a look at debug value loss in instcombine? I started looking at this issue circa r323570 but got sidetracked with other work.

Anastasis has a great writeup on his blog about how to find bugs in this area. See: https://gramanas.github.io/posts/finding-debuginfo-loss/.

Here's one example you might look at:

$ ./bin/opt -enable-debugify -instcombine ../llvm/test/Transforms/InstCombine/zext.ll -S -o -
ERROR: Missing variable 5
...

Each missing variable corresponds to some DILocalVariable which has no corresponding llvm.dbg.value instruction. Ideally we'd be able to emit a debug intrinsic for each variable using simple and non-intrusive methods. Keep in mind that this may not always be possible.

thanks,
vedant

> On Jun 4, 2018, at 1:15 PM, Son Tuan Vu via Phabricator <reviews at reviews.llvm.org> wrote:
> 
> tyb0807 added a comment.
> 
> I get it now. Thank you for your time. So anything else that needs to be fixed? Otherwise I'll tackle the verify-each mode
> 
> 
> https://reviews.llvm.org/D46815
> 
> 
>