[llvm] [LSV] Merge contiguous chains across scalar types (PR #154069)

[Drew Kersnar via llvm-commits]

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@@ -338,12 +334,22 @@ class Vectorizer {
   EquivalenceClassMap collectEquivalenceClasses(BasicBlock::iterator Begin,
                                                 BasicBlock::iterator End);
 
+  /// Inserts a cast instruction to convert Inst to DstTy.
+  Value *insertCast(Value *Val, Type *DstTy);
+
   /// Partitions Instrs into "chains" where every instruction has a known
   /// constant offset from the first instr in the chain.
   ///
   /// Postcondition: For all i, ret[i][0].second == 0, because the first instr
   /// in the chain is the leader, and an instr touches distance 0 from itself.
   std::vector<Chain> gatherChains(ArrayRef<Instruction *> Instrs);
+
+  // Helpers for chain merging.
+  std::optional<APInt> computeLeaderDelta(Instruction *I1, Instruction *I2);
+  bool chainsOverlapAfterRebase(const Chain &A, const Chain &B,
+                                const APInt &Delta) const;
+  static void rebaseChain(Chain &C, const APInt &Delta);
+  void normalizeChainToType(Chain &C, Type *CastTy);
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dakersnar wrote:

It would be nice to have comments above each of these, matching the rest of the file.

https://github.com/llvm/llvm-project/pull/154069