Fix non-deterministic behavior.

We use CSEBlocks to initialize a worklist:

SmallVector<BasicBlock *, 8> CSEWorkList(CSEBlocks.begin(), CSEBlocks.end());

so it must have a deterministic order.

llvm-svn: 196520

llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp

@@ -521,7 +521,7 @@ private:
   /// Holds all of the instructions that we gathered.
   SetVector<Instruction *> GatherSeq;
   /// A list of blocks that we are going to CSE.
-  SmallSet<BasicBlock *, 8> CSEBlocks;
+  SetVector<BasicBlock *> CSEBlocks;
 
   /// Numbers instructions in different blocks.
   DenseMap<BasicBlock *, BlockNumbering> BlocksNumbers;