Revert b95a570 and db16a7c. The change for returning PartialAlias

to returning MayAlias is causing miscompiles in flang.

Author: schweitzpgi

lib/Analysis/BasicAliasAnalysis.cpp

@@ -1231,7 +1231,7 @@ AliasResult BasicAAResult::aliasGEP(const GEPOperator *GEP1, uint64_t V1Size,
     // If we get a No or May, then return it immediately, no amount of analysis
     // will improve this situation.
     if (BaseAlias != MustAlias) {
-      assert(BaseAlias == NoAlias || BaseAlias == MayAlias);
+      //assert(BaseAlias == NoAlias || BaseAlias == MayAlias);
       return BaseAlias;
     }
 
@@ -1278,7 +1278,7 @@ AliasResult BasicAAResult::aliasGEP(const GEPOperator *GEP1, uint64_t V1Size,
       // cannot alias per GEP semantics: "Any memory access must be done through
       // a pointer value associated with an address range of the memory access,
       // otherwise the behavior is undefined.".
-      assert(R == NoAlias || R == MayAlias);
+      //assert(R == NoAlias || R == MayAlias);
       return R;
     }