[Attributor] Add checks needed as we strengthen value simplify

Author: jdoerfert

llvm/lib/Transforms/IPO/Attributor.cpp

@@ -2002,8 +2002,12 @@ ChangeStatus Attributor::cleanupIR() {
     for (auto &U : OldV->uses())
       if (Entry.second || !U.getUser()->isDroppable())
         Uses.push_back(&U);
-    for (Use *U : Uses)
+    for (Use *U : Uses) {
+      if (auto *I = dyn_cast<Instruction>(U->getUser()))
+        if (!isRunOn(*I->getFunction()))
+          continue;
       ReplaceUse(U, NewV);
+    }
   }
 
   for (auto &V : InvokeWithDeadSuccessor)

llvm/lib/Transforms/IPO/AttributorAttributes.cpp

@@ -4895,8 +4895,13 @@ struct AAInstanceInfoImpl : public AAInstanceInfo {
         const auto &ArgInstanceInfoAA = A.getAAFor<AAInstanceInfo>(
             *this, IRPosition::callsite_argument(*CB, CB->getArgOperandNo(&U)),
             DepClassTy::OPTIONAL);
-        if (ArgInstanceInfoAA.isAssumedUniqueForAnalysis())
-          return true;
+        if (!ArgInstanceInfoAA.isAssumedUniqueForAnalysis())
+          return false;
+        // If this call base might reach the scope again we might forward the
+        // argument back here. This is very conservative.
+        if (AA::isPotentiallyReachable(A, *CB, *Scope, *this, nullptr))
+          return false;
+        return true;
       }
       return false;
     };
@@ -5201,6 +5206,8 @@ ChangeStatus AANoCaptureImpl::updateImpl(Attributor &A) {
   //       AAReturnedValues, e.g., track all values that escape through returns
   //       directly somehow.
   auto CheckReturnedArgs = [&](const AAReturnedValues &RVAA) {
+    if (!RVAA.getState().isValidState())
+      return false;
     bool SeenConstant = false;
     for (auto &It : RVAA.returned_values()) {
       if (isa<Constant>(It.first)) {
@@ -6433,6 +6440,8 @@ ChangeStatus AAHeapToStackFunction::updateImpl(Attributor &A) {
           dbgs() << "[H2S] unique free call might free unknown allocations\n");
       return false;
     }
+    if (DI->PotentialAllocationCalls.empty())
+      return true;
     if (DI->PotentialAllocationCalls.size() > 1) {
       LLVM_DEBUG(dbgs() << "[H2S] unique free call might free "
                         << DI->PotentialAllocationCalls.size()