[llvm] [LV]: Teach LV to recursively (de)interleave. (PR #89018)

[Paul Walker via llvm-commits]

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@@ -2862,15 +2874,12 @@ void VPInterleaveRecipe::execute(VPTransformState &State) {
                           &InterleaveFactor](Value *MaskForGaps) -> Value * {
     if (State.VF.isScalable()) {
       assert(!MaskForGaps && "Interleaved groups with gaps are not supported.");
-      assert(InterleaveFactor == 2 &&
+      assert(isPowerOf2_32(InterleaveFactor) &&
              "Unsupported deinterleave factor for scalable vectors");
       auto *ResBlockInMask = State.get(BlockInMask);
-      SmallVector<Value *, 2> Ops = {ResBlockInMask, ResBlockInMask};
-      auto *MaskTy = VectorType::get(State.Builder.getInt1Ty(),
-                                     State.VF.getKnownMinValue() * 2, true);
-      return State.Builder.CreateIntrinsic(
-          MaskTy, Intrinsic::vector_interleave2, Ops,
-          /*FMFSource=*/nullptr, "interleaved.mask");
+      SmallVector<Value *> Ops;
+      Ops.resize(InterleaveFactor, ResBlockInMask);
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paulwalker-arm wrote:

Not 100% sure but does `SmallVector<Value *> Ops(InterleaveFactor, ResBlockInMask);` do the same thing?

https://github.com/llvm/llvm-project/pull/89018