[PATCH] D116928: [LoopVectorize] Support epilogue vectorisation of loops with reductions

[Kerry McLaughlin via Phabricator via llvm-commits]

kmclaughlin added inline comments.


================
Comment at: llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:8273
+
+  for (PHINode *Phi : PhisInBlock) {
+    Phi->replaceIncomingBlockWith(
----------------
david-arm wrote:
> nit: Is it possible to merge these two for loops together into one, i.e.
> 
>   for (PHINode &Phi : VecEpilogueIterationCountCheck->phis()) {
Hi @david-arm, I found that when I tried to use one loop here as you've suggested, that the bc.merge.rdx phis for loops with more than one reduction were not all updated correctly. When I added the test with a loop containing two reductions, the second reduction was not updated and moved to the preheader.


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  https://reviews.llvm.org/D116928/new/

https://reviews.llvm.org/D116928