[llvm] [VPlan] Hook IR blocks into VPlan during skeleton creation (NFC) (PR #114292)

[via llvm-commits]

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@@ -3235,13 +3235,21 @@ void VPWidenPointerInductionRecipe::print(raw_ostream &O, const Twine &Indent,
 
 void VPExpandSCEVRecipe::execute(VPTransformState &State) {
   assert(!State.Lane && "cannot be used in per-lane");
+  if (State.ExpandedSCEVs.contains(Expr)) {
+    // SCEV Expr has already been expanded, result must already be set. At the
+    // moment we have to execute the entry block twice (once before skeleton
+    // creation to get expanded SCEVs used by the skeleton and once during
+    // regular VPlan execution).
+    State.Builder.SetInsertPoint(State.CFG.VPBB2IRBB[getParent()]);
+    assert(State.get(this, VPLane(0)) == State.ExpandedSCEVs[Expr] &&
+           "Results must match");
+    return;
+  }
+
   const DataLayout &DL = State.CFG.PrevBB->getDataLayout();
   SCEVExpander Exp(SE, DL, "induction");
-
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ayalz wrote:

(ok, unrelated)

https://github.com/llvm/llvm-project/pull/114292