[LV] Avoid building interleaved group in presence of WAW dependency

Reviewers: hsaito, Ayal, fhahn, anna, mkazantsev

Reviewed By: hsaito

Patch by evrevnov, thanks!

Differential Revision: https://reviews.llvm.org/D63981

llvm-svn: 367654
diff --git a/llvm/lib/Analysis/VectorUtils.cpp b/llvm/lib/Analysis/VectorUtils.cpp
index 986756e..8bc9104 100644
--- a/llvm/lib/Analysis/VectorUtils.cpp
+++ b/llvm/lib/Analysis/VectorUtils.cpp
@@ -964,6 +964,10 @@
         // instructions that precede it.
         if (isInterleaved(A)) {
           InterleaveGroup<Instruction> *StoreGroup = getInterleaveGroup(A);
+
+          LLVM_DEBUG(dbgs() << "LV: Invalidated store group due to "
+                               "dependence between " << *A << " and "<< *B << '\n');
+
           StoreGroups.remove(StoreGroup);
           releaseGroup(StoreGroup);
         }