[llvm] [SLP] Add store-to-load forwarding conflict cost for widened store chains (PR #199606)

[Alexey Bataev via llvm-commits]

================
@@ -19447,6 +19476,27 @@ BoUpSLP::calculateTreeCostAndTrimNonProfitable(ArrayRef<Value *> VectorizedVals,
            "Expected gather nodes with users only.");
 
     InstructionCost C = getEntryCost(&TE, VectorizedVals, CheckedExtracts);
+    // Also model hazards introduced by a vector load node when the relevant
+    // stores are not part of the current vectorized store tree.
+    if (EnableSLPStoreLoadForwardCheck && TE.hasState() &&
+        TE.State == TreeEntry::Vectorize &&
+        TE.getOpcode() == Instruction::Load &&
+        (CostKind == TTI::TCK_RecipThroughput ||
+         CostKind == TTI::TCK_Latency)) {
+      auto *BaseLoad = cast<LoadInst>(TE.getMainOp());
+      if (findStoreLoadForwardingHazardForLoad(BaseLoad,
+                                               TE.getVectorFactor())) {
+        Type *VecTy = getWidenedType(BaseLoad->getType(), TE.getVectorFactor());
----------------
alexey-bataev wrote:

```suggestion
        Type *VecTy = getWidenedType(BaseLoad->getType(), TE.Scalars.size());
```

https://github.com/llvm/llvm-project/pull/199606