[PATCH] D26212: IRMover: Avoid accidentally mapping types from the destination module (PR30799)

[Hans Wennborg via llvm-commits]

hans added inline comments.


================
Comment at: test/LTO/X86/type-mapping-bug.ll:3
+; RUN: llvm-as -o %t.src.bc %S/Inputs/type-mapping-src.ll
+; RUN: llvm-lto %t.dst.bc %t.src.bc -o=/dev/null
+
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mehdi_amini wrote:
> hans wrote:
> > pcc wrote:
> > > Would it be possible to write this test with `llvm-link` instead of `llvm-lto`?
> > Sadly, I wasn't able to reproduce this with llvm-link, only with llvm-lto.
> > 
> > Some code path must be different. While I think it should be possible to trigger the same problem there, I couldn't figure out how to do it.
> Likely not. I fixed a similar issues in r280599 / D23841 and it requires the LLVMContext to be initialized with ODR type uniquing, which only happens in LTO. (We may be able to add an option to llvm-link, but we can't really test it as it is supposed to be "NFC").
Thanks for the pointer! Yes, that must be it.
I'm kind of happy to see someone else has run into this. I thought I was about to go mad debugging it :-)


https://reviews.llvm.org/D26212