[llvm] [SLP] Split blocking build-vector stores in scalar chains (PR #194970)

[Yaxun Liu via llvm-commits]

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@@ -27265,6 +27267,183 @@ bool SLPVectorizerPass::vectorizeStores(
   return Changed;
 }
 
+static bool collectBuildVector(Value *V, SmallVectorImpl<Value *> &Elts,
+                               SmallVectorImpl<Instruction *> *Insts = nullptr) {
+  auto *VecTy = dyn_cast<FixedVectorType>(V->getType());
+  if (!VecTy)
+    return false;
+  Elts.assign(VecTy->getNumElements(), nullptr);
+  Value *Cur = V;
+  while (auto *IE = dyn_cast<InsertElementInst>(Cur)) {
+    auto *Idx = dyn_cast<ConstantInt>(IE->getOperand(2));
+    if (!Idx || Idx->getValue().uge(Elts.size()))
+      return false;
+    Elts[Idx->getZExtValue()] = IE->getOperand(1);
+    if (Insts)
+      Insts->push_back(IE);
+    Cur = IE->getOperand(0);
+  }
+  if (!isa<PoisonValue, UndefValue>(Cur))
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yxsamliu wrote:

fixed

https://github.com/llvm/llvm-project/pull/194970