[PATCH] D24693: [CodeGen] Don't emit lifetime intrinsics for some local variables

Akira Hatanaka via cfe-commits cfe-commits at lists.llvm.org
Thu Sep 22 14:07:40 PDT 2016

ahatanak added a comment.

Thank you for the great example! I can now see this patch does fix mis-compiles.

There are probably other lifetime bugs you'll see when the code being compiled includes gotos that jump past variable declarations, including the one here: http://lists.llvm.org/pipermail/cfe-dev/2016-July/050066.html. Do you think you can extend the approach taken in this patch to prevent mis-compiles for those too?

Also, rather than removing the intrinsics altogether, have you considered making changes to IRGen to insert them to different locations or insert extra lifetime.starts? In your example, if I insert lifetime.start for "tmp" at the beginning of label "l1", it doesn't assert. I made the same changes for the example I sent to cfe-dev, but it didn't work because DSE removed the store to "i" (if I disable DSE, I see the expected result).


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