[Attributor] Fix AAExecutionDomain returning true on invalid states

[jhuber6]

Summary

This patch fixes a problem with the AAExecutionDomain attributor not
checking if it is in a valid state. This can cause it to incorrectly
return that a block is executed in a single threaded context after the
attributor failed for any reason.

[jdoerfert]

We need a test. A callback call should do it.

llvm/lib/Transforms/IPO/OpenMPOpt.cpp

struct AAExecutionDomainFunction : public AAExecutionDomain {
   ChangeStatus updateImpl(Attributor &A) override;
 
   /// Check if an instruction is executed by a single thread.
   bool isExecutedByInitialThreadOnly(const Instruction &I) const override {
     return isExecutedByInitialThreadOnly(*I.getParent());
   }
 
   bool isExecutedByInitialThreadOnly(const BasicBlock &BB) const override {
-    return SingleThreadedBBs.contains(&BB);
+    return isValidState() && SingleThreadedBBs.contains(&BB);
   }
 
   /// Set of basic blocks that are executed by a single thread.
   DenseSet<const BasicBlock *> SingleThreadedBBs;
 
   /// Total number of basic blocks in this function.
   long unsigned NumBBs;
 };
 
 ChangeStatus AAExecutionDomainFunction::updateImpl(Attributor &A) {
   Function *F = getAnchorScope();
   ReversePostOrderTraversal<Function *> RPOT(F);
   auto NumSingleThreadedBBs = SingleThreadedBBs.size();
 
   bool AllCallSitesKnown;
   auto PredForCallSite = [&](AbstractCallSite ACS) {
     const auto &ExecutionDomainAA = A.getAAFor<AAExecutionDomain>(
         *this, IRPosition::function(*ACS.getInstruction()->getFunction()),
         DepClassTy::REQUIRED);
-    return ExecutionDomainAA.isExecutedByInitialThreadOnly(
+    return ACS.isDirectCall() &&
+           ExecutionDomainAA.isExecutedByInitialThreadOnly(
                *ACS.getInstruction());
   };
 
   if (!A.checkForAllCallSites(PredForCallSite, *this,
                               /* RequiresAllCallSites */ true,
                               AllCallSitesKnown))
     SingleThreadedBBs.erase(&F->getEntryBlock());
 
   // Check if the edge into the successor block compares a thread-id function to