Reverts commit r301424, r301425 and r301426

Commits were:

"Use WeakVH instead of WeakTrackingVH in AliasSetTracker's UnkownInsts"
"Add a new WeakVH value handle; NFC"
"Rename WeakVH to WeakTrackingVH; NFC"

The changes assumed pointers are 8 byte aligned on all architectures.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@301429 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Analysis/CallGraphSCCPass.cpp

@@ -204,7 +204,7 @@ bool CGPassManager::RefreshCallGraph(const CallGraphSCC &CurSCC, CallGraph &CG,
     // Get the set of call sites currently in the function.
     for (CallGraphNode::iterator I = CGN->begin(), E = CGN->end(); I != E; ) {
       // If this call site is null, then the function pass deleted the call
-      // entirely and the WeakTrackingVH nulled it out.
+      // entirely and the WeakVH nulled it out.  
       if (!I->first ||
           // If we've already seen this call site, then the FunctionPass RAUW'd
           // one call with another, which resulted in two "uses" in the edge
@@ -345,10 +345,10 @@ bool CGPassManager::RefreshCallGraph(const CallGraphSCC &CurSCC, CallGraph &CG,
     if (NumIndirectRemoved > NumIndirectAdded &&
         NumDirectRemoved < NumDirectAdded)
       DevirtualizedCall = true;
-
+    
     // After scanning this function, if we still have entries in callsites, then
-    // they are dangling pointers.  WeakTrackingVH should save us for this, so
-    // abort if this happens.
+    // they are dangling pointers.  WeakVH should save us for this, so abort if
+    // this happens.
     assert(CallSites.empty() && "Dangling pointers found in call sites map");
     
     // Periodically do an explicit clear to remove tombstones when processing