[llvm] [VPlan] Fix packed replication of struct types (PR #160274)

[Luke Lau via llvm-commits]

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@@ -3267,11 +3267,23 @@ void VPPredInstPHIRecipe::execute(VPTransformState &State) {
   // also do that packing, thereby "hoisting" the insert-element sequence.
   // Otherwise, a phi node for the scalar value is needed.
   if (State.hasVectorValue(getOperand(0))) {
-    Value *VectorValue = State.get(getOperand(0));
-    InsertElementInst *IEI = cast<InsertElementInst>(VectorValue);
-    PHINode *VPhi = State.Builder.CreatePHI(IEI->getType(), 2);
-    VPhi->addIncoming(IEI->getOperand(0), PredicatingBB); // Unmodified vector.
-    VPhi->addIncoming(IEI, PredicatedBB); // New vector with inserted element.
+    auto *VecI = cast<Instruction>(State.get(getOperand(0)));
+    assert(isa<InsertElementInst>(VecI) ||
+           isa<InsertValueInst>(VecI) &&
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lukel97 wrote:

I tried this originally but there's something about it being in an assert macro that causes an error. It's not able to see the parameter pack isa overload for some reason 

https://github.com/llvm/llvm-project/pull/160274