[llvm] [SLP]Initial support for (masked)loads + compress and (masked)interleaved (PR #132099)

[Simon Pilgrim via llvm-commits]

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@@ -5214,6 +5221,145 @@ static Value *createExtractVector(IRBuilderBase &Builder, Value *Vec,
   return Builder.CreateShuffleVector(Vec, Mask);
 }
 
+/// Builds compress-like mask for shuffles for the given \p PointerOps, ordered
+/// with \p Order.
+static void buildCompressMask(ArrayRef<Value *> PointerOps,
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RKSimon wrote:

Worth returning true (or std::optional<unsigned>) here if the compression stride is uniform?

https://github.com/llvm/llvm-project/pull/132099