[llvm] Fix crash when complex deinterleaving operates on an unrolled loop

llvm/lib/CodeGen/ComplexDeinterleavingPass.cpp

@@ -1741,6 +1741,17 @@ void ComplexDeinterleavingGraph::identifyReductionNodes() {
       LLVM_DEBUG(
           dbgs() << "Identified single reduction starting from instruction: "
                  << *Real << "/" << *ReductionInfo[Real].second << "\n");
+
+      // Reducing to a single vector is not supported, only permit reducing down
+      // to scalar values.
+      // Doing this here will leave the prior node in the graph,
+      // however with no uses the node will be unreachable by the replacement
+      // process. That along with the usage outside the graph should prevent the
+      // replacement process from kicking off at all for this graph.
+      // TODO Add support for reducing to a single vector value
+      if (ReductionInfo[Real].second->getType()->isVectorTy())
+        continue;
+
       Processed[i] = true;
       auto RootNode = prepareCompositeNode(
           ComplexDeinterleavingOperation::ReductionSingle, Real, nullptr);