[llvm] [InterleavedAccess] Construct interleaved access store with shuffles (PR #164000)

[via llvm-commits]

ram-NK wrote:

``` 
 // Getting all the interleaved operands.
  while (ConcatLevel > 1) {
    unsigned InterleavedOperands = Shuffles.size();
    for (unsigned i = 0; i < InterleavedOperands; i++) {
      ShuffleVectorInst *SFL = dyn_cast<ShuffleVectorInst>(Shuffles.front());
      if (!SFL)
        return false;

+     if (SVI != SFL && !SFL->isConcat())
+       return false;

      Shuffles.pop_front();

      Value *Op0 = SFL->getOperand(0);
      Value *Op1 = SFL->getOperand(1);

      Shuffles.push_back(dyn_cast<Value>(Op0));
      Shuffles.push_back(dyn_cast<Value>(Op1));
    }
    ConcatLevel >>= 1;
  }
```

isConcat() of ShuffleVectorInst will ensure the correctness of this interleaving logic. I tested with two cases.  Works fine for me. 

https://github.com/llvm/llvm-project/pull/164000