[llvm] [Transform][LoadStoreVectorizer] allow redundant in Chain (PR #163019)

[Matt Arsenault via llvm-commits]

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@@ -626,26 +626,38 @@ std::vector<Chain> Vectorizer::splitChainByContiguity(Chain &C) {
   std::vector<Chain> Ret;
   Ret.push_back({C.front()});
 
+  unsigned ElemBytes = DL.getTypeStoreSize(getChainElemTy(C));
+  APInt PrevReadEnd = C[0].OffsetFromLeader +
+                      DL.getTypeSizeInBits(getLoadStoreType(&*C[0].Inst)) / 8;
   for (auto It = std::next(C.begin()), End = C.end(); It != End; ++It) {
     // `prev` accesses offsets [PrevDistFromBase, PrevReadEnd).
     auto &CurChain = Ret.back();
-    const ChainElem &Prev = CurChain.back();
-    unsigned SzBits = DL.getTypeSizeInBits(getLoadStoreType(&*Prev.Inst));
+    unsigned SzBits = DL.getTypeSizeInBits(getLoadStoreType(&*It->Inst));
     assert(SzBits % 8 == 0 && "Non-byte sizes should have been filtered out by "
                               "collectEquivalenceClass");
-    APInt PrevReadEnd = Prev.OffsetFromLeader + SzBits / 8;
 
     // Add this instruction to the end of the current chain, or start a new one.
-    bool AreContiguous = It->OffsetFromLeader == PrevReadEnd;
-    LLVM_DEBUG(dbgs() << "LSV: Instructions are "
-                      << (AreContiguous ? "" : "not ") << "contiguous: "
-                      << *Prev.Inst << " (ends at offset " << PrevReadEnd
-                      << ") -> " << *It->Inst << " (starts at offset "
+    uint64_t SzBytes = SzBits / 8;
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arsenm wrote:

Not sure why this was and is mixing getTypeStoreSize with getTypeSizeInBits and manually computing bytes? Just consistently use getTypeStoreSize? 

https://github.com/llvm/llvm-project/pull/163019