[SimpleLoopUnswitch] Increment stats counter for unswitching switch instruction

[qianzhen]

Summary

Increment statistics counter NumSwitches at unswitchNontrivialInvariants() for unswitching a non-trivial switch instruction. This is to fix a bug that it increments NumBranches even for the case of switch instruction.
There is no functional change in this patch.

[asbirlea]

One nit, otherwise LGTM.

llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp

2286

The if(SI) is redundant.
Lines 1923 and 2028 above already confirm either SI or BI exist.

[qianzhen]

Removed "if (SI)" as comment suggested. Thanks for the review!

llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp

#endif
   for (Loop *UpdatedL : llvm::concat<Loop *>(NonChildClonedLoops, HoistedLoops))
     if (UpdatedL->getParentLoop() == ParentL)
       SibLoops.push_back(UpdatedL);
   UnswitchCB(IsStillLoop, SibLoops);
 
   if (MSSAU && VerifyMemorySSA)
     MSSAU->getMemorySSA()->verifyMemorySSA();
 
+  if (BI)
     ++NumBranches;
+  else 
+    ++NumSwitches;
 }
 
 /// Recursively compute the cost of a dominator subtree based on the per-block
 /// cost map provided.
 ///
 /// The recursive computation is memozied into the provided DT-indexed cost map
 /// to allow querying it for most nodes in the domtree without it becoming
 /// quadratic.