1 files changed, 7 insertions, 10 deletions
diff --git a/llvm/lib/Analysis/BasicAliasAnalysis.cpp b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
index fe0426a..fa03a82 100644
--- a/llvm/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
@@ -1403,14 +1403,8 @@ AliasResult BasicAAResult::aliasPHI(const PHINode *PN, LocationSize PNSize,
   // different loop iterations.
   SaveAndRestore<bool> SavedMayBeCrossIteration(MayBeCrossIteration, true);
 
-  // If we enabled the MayBeCrossIteration flag, alias analysis results that
-  // have been cached earlier may no longer be valid. Perform recursive queries
-  // with a new AAQueryInfo.
-  AAQueryInfo NewAAQI = AAQI.withEmptyCache();
-  AAQueryInfo *UseAAQI = !SavedMayBeCrossIteration.get() ? &NewAAQI : &AAQI;
-
   AliasResult Alias = AAQI.AAR.alias(MemoryLocation(V1Srcs[0], PNSize),
-                                     MemoryLocation(V2, V2Size), *UseAAQI);
+                                     MemoryLocation(V2, V2Size), AAQI);
 
   // Early exit if the check of the first PHI source against V2 is MayAlias.
   // Other results are not possible.
@@ -1427,7 +1421,7 @@ AliasResult BasicAAResult::aliasPHI(const PHINode *PN, LocationSize PNSize,
     Value *V = V1Srcs[i];
 
     AliasResult ThisAlias = AAQI.AAR.alias(
-        MemoryLocation(V, PNSize), MemoryLocation(V2, V2Size), *UseAAQI);
+        MemoryLocation(V, PNSize), MemoryLocation(V2, V2Size), AAQI);
     Alias = MergeAliasResults(ThisAlias, Alias);
     if (Alias == AliasResult::MayAlias)
       break;
@@ -1544,8 +1538,11 @@ AliasResult BasicAAResult::aliasCheck(const Value *V1, LocationSize V1Size,
     return AliasResult::MayAlias;
 
   // Check the cache before climbing up use-def chains. This also terminates
-  // otherwise infinitely recursive queries.
-  AAQueryInfo::LocPair Locs({V1, V1Size}, {V2, V2Size});
+  // otherwise infinitely recursive queries. Include MayBeCrossIteration in the
+  // cache key, because some cases where MayBeCrossIteration==false returns
+  // MustAlias or NoAlias may become MayAlias under MayBeCrossIteration==true.
+  AAQueryInfo::LocPair Locs({V1, V1Size, MayBeCrossIteration},
+                            {V2, V2Size, MayBeCrossIteration});
   const bool Swapped = V1 > V2;
   if (Swapped)
     std::swap(Locs.first, Locs.second);