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

[Alexey Bataev 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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alexey-bataev wrote:

Hi Valery, you can add this option in the downstream compiler, should not be a very big change.

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