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.

llvm-svn: 301429
diff --git a/llvm/lib/Analysis/ScalarEvolutionExpander.cpp b/llvm/lib/Analysis/ScalarEvolutionExpander.cpp
index f8338e8..6dd1044 100644
--- a/llvm/lib/Analysis/ScalarEvolutionExpander.cpp
+++ b/llvm/lib/Analysis/ScalarEvolutionExpander.cpp
@@ -1772,10 +1772,9 @@
 ///
 /// This does not depend on any SCEVExpander state but should be used in
 /// the same context that SCEVExpander is used.
-unsigned
-SCEVExpander::replaceCongruentIVs(Loop *L, const DominatorTree *DT,
-                                  SmallVectorImpl<WeakTrackingVH> &DeadInsts,
-                                  const TargetTransformInfo *TTI) {
+unsigned SCEVExpander::replaceCongruentIVs(Loop *L, const DominatorTree *DT,
+                                           SmallVectorImpl<WeakVH> &DeadInsts,
+                                           const TargetTransformInfo *TTI) {
   // Find integer phis in order of increasing width.
   SmallVector<PHINode*, 8> Phis;
   for (auto &I : *L->getHeader()) {