[llvm] [SLP]Buildvector for alternate instructions with non-profitable gather operands. (PR #84978)

[Valery Dmitriev via llvm-commits]

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@@ -6074,6 +6194,14 @@ BoUpSLP::TreeEntry::EntryState BoUpSLP::getScalarsVectorizationState(
       LLVM_DEBUG(dbgs() << "SLP: ShuffleVector are not vectorized.\n");
       return TreeEntry::NeedToGather;
     }
+    if (!areAltOperandsProfitable(S, VL)) {
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valerydmit wrote:

Of course we can. That will just adds another piece of divergence for things that should not really have existed from the very beginning. I believe similar problem may exist in llvm-project.


https://github.com/llvm/llvm-project/pull/84978