2 files changed, 23 insertions, 8 deletions

diff --git a/llvm/lib/Analysis/BasicAliasAnalysis.cpp b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
index 3db041cc0fa..53782302030 100644
--- a/llvm/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
@@ -924,8 +924,8 @@ static AliasResult aliasSameBasePointerGEPs(const GEPOperator *GEP1,
                                             uint64_t V2Size,
                                             const DataLayout &DL) {
 
-  assert(GEP1->getPointerOperand()->stripPointerCasts() ==
-             GEP2->getPointerOperand()->stripPointerCasts() &&
+  assert(GEP1->getPointerOperand()->stripPointerCastsAndBarriers() ==
+             GEP2->getPointerOperand()->stripPointerCastsAndBarriers() &&
          GEP1->getPointerOperandType() == GEP2->getPointerOperandType() &&
          "Expected GEPs with the same pointer operand");
 
@@ -1184,8 +1184,8 @@ AliasResult BasicAAResult::aliasGEP(const GEPOperator *GEP1, uint64_t V1Size,
     // If we know the two GEPs are based off of the exact same pointer (and not
     // just the same underlying object), see if that tells us anything about
     // the resulting pointers.
-    if (GEP1->getPointerOperand()->stripPointerCasts() ==
-            GEP2->getPointerOperand()->stripPointerCasts() &&
+    if (GEP1->getPointerOperand()->stripPointerCastsAndBarriers() ==
+            GEP2->getPointerOperand()->stripPointerCastsAndBarriers() &&
         GEP1->getPointerOperandType() == GEP2->getPointerOperandType()) {
       AliasResult R = aliasSameBasePointerGEPs(GEP1, V1Size, GEP2, V2Size, DL);
       // If we couldn't find anything interesting, don't abandon just yet.
@@ -1500,8 +1500,8 @@ AliasResult BasicAAResult::aliasCheck(const Value *V1, uint64_t V1Size,
     return NoAlias;
 
   // Strip off any casts if they exist.
-  V1 = V1->stripPointerCasts();
-  V2 = V2->stripPointerCasts();
+  V1 = V1->stripPointerCastsAndBarriers();
+  V2 = V2->stripPointerCastsAndBarriers();
 
   // If V1 or V2 is undef, the result is NoAlias because we can always pick a
   // value for undef that aliases nothing in the program.
diff --git a/llvm/lib/IR/Value.cpp b/llvm/lib/IR/Value.cpp
index b07c57685a2..d83bdf2acd4 100644
--- a/llvm/lib/IR/Value.cpp
+++ b/llvm/lib/IR/Value.cpp
@@ -432,6 +432,7 @@ namespace {
 enum PointerStripKind {
   PSK_ZeroIndices,
   PSK_ZeroIndicesAndAliases,
+  PSK_ZeroIndicesAndAliasesAndBarriers,
   PSK_InBoundsConstantIndices,
   PSK_InBounds
 };
@@ -450,6 +451,7 @@ static const Value *stripPointerCastsAndOffsets(const Value *V) {
     if (auto *GEP = dyn_cast<GEPOperator>(V)) {
       switch (StripKind) {
       case PSK_ZeroIndicesAndAliases:
+      case PSK_ZeroIndicesAndAliasesAndBarriers:
       case PSK_ZeroIndices:
         if (!GEP->hasAllZeroIndices())
           return V;
@@ -472,12 +474,20 @@ static const Value *stripPointerCastsAndOffsets(const Value *V) {
         return V;
       V = GA->getAliasee();
     } else {
-      if (auto CS = ImmutableCallSite(V))
+      if (auto CS = ImmutableCallSite(V)) {
         if (const Value *RV = CS.getReturnedArgOperand()) {
           V = RV;
           continue;
         }
-
+        // The result of invariant.group.barrier must alias it's argument,
+        // but it can't be marked with returned attribute, that's why it needs
+        // special case.
+        if (StripKind == PSK_ZeroIndicesAndAliasesAndBarriers &&
+            CS.getIntrinsicID() == Intrinsic::invariant_group_barrier) {
+          V = CS.getArgOperand(0);
+          continue;
+        }
+      }
       return V;
     }
     assert(V->getType()->isPointerTy() && "Unexpected operand type!");
@@ -499,6 +509,11 @@ const Value *Value::stripInBoundsConstantOffsets() const {
   return stripPointerCastsAndOffsets<PSK_InBoundsConstantIndices>(this);
 }
 
+const Value *Value::stripPointerCastsAndBarriers() const {
+  return stripPointerCastsAndOffsets<PSK_ZeroIndicesAndAliasesAndBarriers>(
+      this);
+}
+
 const Value *
 Value::stripAndAccumulateInBoundsConstantOffsets(const DataLayout &DL,
                                                  APInt &Offset) const {