[PATCH] D88823: [CodeGen][TailDuplicator] Don't duplicate blocks with INLINEASM_BR

[Nick Desaulniers via Phabricator via llvm-commits]

nickdesaulniers added a comment.

> In all these sorts of bugs, it's useful to ask why it's not broken with invoke (in case it is!). In this case, it looks like what prevents this bug from occurring for invoke is that EH_LABEL is marked isNotDuplicable = 1, checked a few lines up from your change. So, good.

Ah, that's another thing I was looking at when I said

>> Or if duplicating the INLINEASM_BR results in multiple side effects? (Even if the code is never run, the kernel uses .pushsection to squirrel away data in these, so tail duplication is duplicating the data. Is that a problem? Not sure yet.)



> I think the fix you have here is OK for now, if you fix the test and commentary.
> As a follow-on, we could re-allow tail duplication, but actually place the copies in the correct location, by calling llvm::findPHICopyInsertPoint within TailDuplicator::appendCopies.

I agree.


Repository:
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  https://reviews.llvm.org/D88823/new/

https://reviews.llvm.org/D88823