1. Fix a bug in getTypeConversion. When a *simple* type is split, we need to return the type of the split result.

2. Change the maximum vectorization width from 4 to 8.
3. A test for both.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166864 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Vectorize/LoopVectorize.cpp

@@ -317,7 +317,7 @@ public:
   /// Returns the most profitable vectorization factor for the loop that is
   /// smaller or equal to the VF argument. This method checks every power
   /// of two up to VF.
-  unsigned findBestVectorizationFactor(unsigned VF = 4);
+  unsigned findBestVectorizationFactor(unsigned VF = 8);
 
 private:
   /// Returns the expected execution cost. The unit of the cost does