[llvm] [SLP] More OOP to simplify vectorizeStores() (NFC) (PR #134605)

[Gaëtan Bossu via llvm-commits]

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@@ -20851,52 +20887,35 @@ bool SLPVectorizerPass::vectorizeStores(
   // dependencies and no need to waste compile time to try to vectorize them.
   // - Try to vectorize the sequence {1, {1, 0}, {3, 2}}.
   auto FillStoresSet = [&](unsigned Idx, StoreInst *SI) {
-    for (RelatedStoreInsts &StoreSeq : SortedStores) {
-      std::optional<int> Diff = getPointersDiff(
-          Stores[StoreSeq.BaseInstrIdx]->getValueOperand()->getType(),
-          Stores[StoreSeq.BaseInstrIdx]->getPointerOperand(),
-          SI->getValueOperand()->getType(), SI->getPointerOperand(), *DL, *SE,
-          /*StrictCheck=*/true);
-      if (!Diff)
-        continue;
-      std::optional<unsigned> PrevInst =
-          StoreSeq.insertOrLookup(/*InstrIdx=*/Idx, /*PtrDist=*/*Diff);
-      if (!PrevInst) {
-        // No store was associated to that distance. Keep collecting.
-        return;
-      }
-      // Try to vectorize the first found set to avoid duplicate analysis.
-      TryToVectorize(StoreSeq.Instrs);
-      RelatedStoreInsts::DistToInstMap PrevSet;
-      copy_if(StoreSeq.Instrs, std::inserter(PrevSet, PrevSet.end()),
-              [&](const std::pair<int, unsigned> &DistAndIdx) {
-                return DistAndIdx.second > *PrevInst;
-              });
-      StoreSeq.reset(Idx);
-      // Insert stores that followed previous match to try to vectorize them
-      // with this store.
-      unsigned StartIdx = *PrevInst + 1;
-      SmallBitVector UsedStores(Idx - StartIdx);
-      // Distances to previously found dup store (or this store, since they
-      // store to the same addresses).
-      SmallVector<int> Dists(Idx - StartIdx, 0);
-      for (auto [PtrDist, InstIdx] : reverse(PrevSet)) {
-        // Do not try to vectorize sequences, we already tried.
-        if (VectorizedStores.contains(Stores[InstIdx]))
-          break;
-        unsigned BI = InstIdx - StartIdx;
-        UsedStores.set(BI);
-        Dists[BI] = PtrDist - *Diff;
-      }
-      for (unsigned I = StartIdx; I < Idx; ++I) {
-        unsigned BI = I - StartIdx;
-        if (UsedStores.test(BI))
-          StoreSeq.insertOrLookup(I, Dists[BI]);
-      }
+    std::optional<int> Diff;
+    auto *RelatedStores =
+        find_if(SortedStores, [&](const RelatedStoreInsts &StoreSeq) {
+          StoreInst &BaseStore = StoreSeq.getBaseStore();
+          Diff = getPointersDiff(BaseStore.getValueOperand()->getType(),
+                                 BaseStore.getPointerOperand(),
+                                 SI->getValueOperand()->getType(),
+                                 SI->getPointerOperand(), *DL, *SE,
+                                 /*StrictCheck=*/true);
+          return Diff.has_value();
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gbossu wrote:

Rebased and added one fixup to explicitly capture the `PtrDist` side effect. I think this is a good compromise and I'd grateful if this change could be committed now. It's not really clear to me why there is this much push back against making the code ever so slightly more maintainable.

https://github.com/llvm/llvm-project/pull/134605