[PATCH] D77635: [LV] Vectorize with FoldTail when Primary Induction is absent

[Serguei Katkov via Phabricator via llvm-commits]

skatkov added a comment.

> Thanks @skatkov. The test compiles for me, and the part that this patch introduces looks correct, but there seems to be a problem with how %tmp8 is handled - as a live-out first-order-recurrence which fold-tail does not handle (the compare it introduces is not used by anyone). To reproduce the bug w/o this patch, transform the loop iv %tmp9 to start at 0 and exit the loop when equal to 4 (instead of starting at 1 and exiting at 5), and add 1 to %tmp8. Would be good to open a PR.
>  Continuing to investigate.

Hi Ayal, thank you for information.
Indeed, I've reduced an original reproducer and found this patch as a first commit exposing the bug.
Would very appreciate if you could fix the real problem!


Repository:
  rG LLVM Github Monorepo

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