[llvm] [VPlan] Implement interleaving as VPlan-to-VPlan transform. (PR #95842)

[via llvm-commits]

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@@ -2502,42 +2535,59 @@ void VPWidenPointerInductionRecipe::execute(VPTransformState &State) {
 
   auto *IVR = getParent()->getPlan()->getCanonicalIV();
   PHINode *CanonicalIV = cast<PHINode>(State.get(IVR, 0, /*IsScalar*/ true));
+  unsigned CurrentPart = 0;
+  if (getNumOperands() == 5)
+    CurrentPart =
+        cast<ConstantInt>(getOperand(4)->getLiveInIRValue())->getZExtValue();
   Type *PhiType = IndDesc.getStep()->getType();
 
   // Build a pointer phi
   Value *ScalarStartValue = getStartValue()->getLiveInIRValue();
   Type *ScStValueType = ScalarStartValue->getType();
-  PHINode *NewPointerPhi = PHINode::Create(ScStValueType, 2, "pointer.phi",
-                                           CanonicalIV->getIterator());
+  PHINode *NewPointerPhi = nullptr;
 
   BasicBlock *VectorPH = State.CFG.getPreheaderBBFor(this);
-  NewPointerPhi->addIncoming(ScalarStartValue, VectorPH);
+  if (getNumOperands() == 5) {
+    auto *GEP = cast<GetElementPtrInst>(State.get(getOperand(3), 0));
+    NewPointerPhi = cast<PHINode>(GEP->getPointerOperand());
+  } else {
+    NewPointerPhi =
+        PHINode::Create(ScStValueType, 2, "pointer.phi", CanonicalIV);
+    NewPointerPhi->addIncoming(ScalarStartValue, VectorPH);
+  }
 
   // A pointer induction, performed by using a gep
   BasicBlock::iterator InductionLoc = State.Builder.GetInsertPoint();
+  unsigned UF = getNumOperands() == 2
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ayalz wrote:

Worth documenting somewhere that that the nNumber of operands is either 2 - w/o unrolling, or 5 - w/ unrolling - where the three additional operands are UF, GEP, Part?

https://github.com/llvm/llvm-project/pull/95842