GVNHoist - silence static analyzer dyn_cast<> null dereference warning in hasEHOrLoadsOnPath call. NFCI.

The static analyzer is warning about a potential null dereference, but we should be able to use cast<> directly and if not assert will fire for us.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@375429 91177308-0d34-0410-b5e6-96231b3b80d8

Author: RKSimon

lib/Transforms/Scalar/GVNHoist.cpp

@@ -539,7 +539,7 @@ class GVNHoist {
 
     // Check for unsafe hoistings due to side effects.
     if (K == InsKind::Store) {
-      if (hasEHOrLoadsOnPath(NewPt, dyn_cast<MemoryDef>(U), NBBsOnAllPaths))
+      if (hasEHOrLoadsOnPath(NewPt, cast<MemoryDef>(U), NBBsOnAllPaths))
         return false;
     } else if (hasEHOnPath(NewBB, OldBB, NBBsOnAllPaths))
       return false;