[OpenMPOPT][NFC] Introducing OMPInformationCache

[sstefan1]

Summary

Introduction of OpenMP-specific information cache based on Attributor's InformationCache. This should make it easier to share information between them.
This also defines some basic information about ICVs in OMPKinds.def.

[sstefan1]

This is the first split of D81788

[jdoerfert]

Can you split the rest into 1) NFC create and populate Cache, and 2) Introduce ICVs. I think the first is trivial. For the second we might need a way to test it. Would be interesting to have a cmd line flag to dump the ICV state at the beginning of each function. For now that would print their defaults but that is fine too.

llvm/lib/Transforms/IPO/OpenMPOpt.cpp

168

Feel free to commit this part as NFC.

[sstefan1]

left out icv part for another patch

[jdoerfert]

LGTM. Thx!

llvm/include/llvm/Frontend/OpenMP/OMPConstants.h

 /// Make the enum values available in the llvm::omp namespace. This allows us to
 /// write something like OMPD_parallel if we have a `using namespace omp`. At
 /// the same time we do not loose the strong type guarantees of the enum class,
 /// that is we cannot pass an unsigned as Directive without an explicit cast.
 #define OMP_DIRECTIVE(Enum, ...) constexpr auto Enum = omp::Directive::Enum;
 #define OMP_CLAUSE(Enum, ...) constexpr auto Enum = omp::Clause::Enum;
 #include "llvm/Frontend/OpenMP/OMPKinds.def"
 
+/// IDs for all Internal Control Variables (ICVs).
+enum class InternalControlVar {
+#define ICV_DATA_ENV(Enum, ...) Enum,
+#include "llvm/Frontend/OpenMP/OMPKinds.def"
+};
+
+#define ICV_DATA_ENV(Enum, ...)                                                \
+  constexpr auto Enum = omp::InternalControlVar::Enum;
+#include "llvm/Frontend/OpenMP/OMPKinds.def"
+
 /// IDs for all omp runtime library (RTL) functions.
 enum class RuntimeFunction {
 #define OMP_RTL(Enum, ...) Enum,
 #include "llvm/Frontend/OpenMP/OMPKinds.def"
 };
 
 #define OMP_RTL(Enum, ...) constexpr auto Enum = omp::RuntimeFunction::Enum;
 #include "llvm/Frontend/OpenMP/OMPKinds.def"

llvm/include/llvm/Frontend/OpenMP/OMPKinds.def

 __OMP_FUNCTION_TYPE(TaskRoutineEntry, false, Int32, Int32,
                     /* kmp_task_t */ VoidPtr)
 
 #undef __OMP_FUNCTION_TYPE
 #undef OMP_FUNCTION_TYPE
 
 ///}
 
+/// Internal Control Variables information
+///
+///{
+
+#ifndef ICV_DATA_ENV
+#define ICV_DATA_ENV(Name, EnvVarName, Init)
+#endif
+
+#define __ICV_DATA_ENV(Name, EnvVarName, Init)                                 \
+  ICV_DATA_ENV(ICV_##Name, #EnvVarName, Init)
+
+__ICV_DATA_ENV(nthreads, OMP_NUM_THREADS, IMPLEMENTATION_DEFINED)
+__ICV_DATA_ENV(__last, last, LAST)
+
+#undef __ICV_DATA_ENV
+#undef ICV_DATA_ENV
+
+#ifndef ICV_RT_SET
+#define ICV_RT_SET(Name, RTL)
+#endif
+
+#define __ICV_RT_SET(Name, RTL) ICV_RT_SET(ICV_##Name, OMPRTL_##RTL)
+
+__ICV_RT_SET(nthreads, omp_set_num_threads)
+
+#undef __ICV_RT_SET
+#undef ICV_RT_SET
+
+#ifndef ICV_RT_GET
+#define ICV_RT_GET(Name, RTL)
+#endif
+
+#define __ICV_RT_GET(Name, RTL) ICV_RT_GET(ICV_##Name, OMPRTL_##RTL)
+
+__ICV_RT_GET(nthreads, omp_get_max_threads)
+
+#undef __ICV_RT_GET
+#undef ICV_RT_GET
+
+///}
+
 /// Runtime library function (and their attributes)
 ///
 ///{
 
 #ifndef OMP_RTL
 #define OMP_RTL(Enum, Str, IsVarArg, ReturnType, ...)
 #endif
 

llvm/lib/Transforms/IPO/OpenMPOpt.cpp

 #include "llvm/Analysis/CallGraph.h"
 #include "llvm/Analysis/CallGraphSCCPass.h"
 #include "llvm/Analysis/OptimizationRemarkEmitter.h"
 #include "llvm/Frontend/OpenMP/OMPConstants.h"
 #include "llvm/Frontend/OpenMP/OMPIRBuilder.h"
 #include "llvm/InitializePasses.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Transforms/IPO.h"
+#include "llvm/Transforms/IPO/Attributor.h"
 #include "llvm/Transforms/Utils/CallGraphUpdater.h"
 
 using namespace llvm;
 using namespace omp;
 using namespace types;
 
 #define DEBUG_TYPE "openmp-opt"
 

 STATISTIC(NumOpenMPRuntimeFunctionUsesIdentified,
           "Number of OpenMP runtime function uses identified");
 
 #if !defined(NDEBUG)
 static constexpr auto TAG = "[" DEBUG_TYPE "]";
 #endif
 
 namespace {
-struct OpenMPOpt {
 
-  using OptimizationRemarkGetter =
-      function_ref<OptimizationRemarkEmitter &(Function *)>;
-
-  OpenMPOpt(SmallVectorImpl<Function *> &SCC,
-            SmallPtrSetImpl<Function *> &ModuleSlice,
-            CallGraphUpdater &CGUpdater, OptimizationRemarkGetter OREGetter)
-      : M(*(*SCC.begin())->getParent()), SCC(SCC), ModuleSlice(ModuleSlice),
-        OMPBuilder(M), CGUpdater(CGUpdater), OREGetter(OREGetter) {
+/// OpenMP specific information. For now, stores RFIs and ICVs also needed for
+/// Attributor runs.
+struct OMPInformationCache : public InformationCache {
+  OMPInformationCache(Module &M, AnalysisGetter &AG,
+                      BumpPtrAllocator &Allocator, SetVector<Function *> *CGSCC,
+                      SmallPtrSetImpl<Function *> &ModuleSlice)
+      : InformationCache(M, AG, Allocator, CGSCC), ModuleSlice(ModuleSlice),
+        OMPBuilder(M) {
     initializeTypes(M);
     initializeRuntimeFunctions();
+    initializeInternalControlVars();
+
     OMPBuilder.initialize();
   }
 
+  /// Generic information that describes an internal control variable.
+  struct InternalControlVarInfo {
+    /// The kind, as described by InternalControlVar enum.
+    InternalControlVar Kind;
+
+    /// Environment variable associated with this ICV.
+    StringRef EnvVarName;
+
+    /// Setter RTL function associated with this ICV.
+    RuntimeFunction Setter;
+
+    /// Getter RTL function associated with this ICV.
+    RuntimeFunction Getter;
+
+    /// RTL Function corresponding to the override clause of this ICV
+    RuntimeFunction Clause;
+  };
+
   /// Generic information that describes a runtime function
   struct RuntimeFunctionInfo {
 
     /// The kind, as described by the RuntimeFunction enum.
     RuntimeFunction Kind;
 
     /// The name of the function.
     StringRef Name;
struct RuntimeFunctionInfo {
     /// Return the number of arguments (or the minimal number for variadic
     /// functions).
     size_t getNumArgs() const { return ArgumentTypes.size(); }
 
     /// Run the callback \p CB on each use and forget the use if the result is
     /// true. The callback will be fed the function in which the use was
     /// encountered as second argument.
     void foreachUse(function_ref<bool(Use &, Function &)> CB) {
+      for (auto &It : UsesMap)
+        foreachUse(CB, It.first, It.second.get());
+    }
+
+    /// Run the callback \p CB on each use within the function \p F and forget
+    /// the use if the result is true.
+    void foreachUse(function_ref<bool(Use &, Function &)> CB, Function *F,
+                    UseVector *Uses = nullptr) {
       SmallVector<unsigned, 8> ToBeDeleted;
-      for (auto &It : UsesMap) {
-        ToBeDeleted.clear();
-        unsigned Idx = 0;
-        UseVector &UV = *It.second;
-        for (Use *U : UV) {
-          if (CB(*U, *It.first))
-            ToBeDeleted.push_back(Idx);
-          ++Idx;
-        }
+
+      UseVector &UV = Uses ? *Uses : getOrCreateUseVector(F);
+
+        if (CB(*U, *F))
 
-        // Remove the to-be-deleted indices in reverse order as prior
-        // modifcations will not modify the smaller indices.
-        while (!ToBeDeleted.empty()) {
-          unsigned Idx = ToBeDeleted.pop_back_val();
-          UV[Idx] = UV.back();
-          UV.pop_back();
-        }
-      }
-    }
 
   private:
     /// Map from functions to all uses of this runtime function contained in
     /// them.
     DenseMap<Function *, std::unique_ptr<UseVector>> UsesMap;
   };
 
+  /// The slice of the module we are allowed to look at.
+  SmallPtrSetImpl<Function *> &ModuleSlice;
+
+  /// An OpenMP-IR-Builder instance
+  OpenMPIRBuilder OMPBuilder;
+
+  /// Map from runtime function kind to the runtime function description.
+  EnumeratedArray<RuntimeFunctionInfo, RuntimeFunction,
+                  RuntimeFunction::OMPRTL___last>
+      RFIs;
+
+  /// Map from ICV kind to the ICV description.
+  EnumeratedArray<InternalControlVarInfo, InternalControlVar,
+                  InternalControlVar::ICV___last>
+      ICVs;
+
+  /// Helper to initialize all internal control variable information for those
+  /// defined in OMPKinds.def.
+  void initializeInternalControlVars() {
+#define ICV_RT_SET(_Name, RTL)                                                 \
+  {                                                                            \
+    auto &ICV = ICVs[_Name];                                                   \
+    ICV.Setter = RTL;                                                          \
+  }
+#define ICV_RT_GET(Name, RTL)                                                  \
+  {                                                                            \
+    auto &ICV = ICVs[Name];                                                    \
+    ICV.Getter = RTL;                                                          \
+  }
+#define ICV_DATA_ENV(Name, _EnvVarName, Init)                                  \
+  {                                                                            \
+    auto &ICV = ICVs[Name];                                                    \
+    ICV.Kind = Name;                                                           \
+    ICV.EnvVarName = _EnvVarName;                                              \
+  }
+#include "llvm/Frontend/OpenMP/OMPKinds.def"
+  }
+
+  /// Returns true if the function declaration \p F matches the runtime
+  /// function types, that is, return type \p RTFRetType, and argument types
+  /// \p RTFArgTypes.
+  static bool declMatchesRTFTypes(Function *F, Type *RTFRetType,
+                                  SmallVector<Type *, 8> &RTFArgTypes) {
+    // TODO: We should output information to the user (under debug output
+    //       and via remarks).
+
+    if (!F)
+      return false;
+    if (F->getReturnType() != RTFRetType)
+      return false;
+    if (F->arg_size() != RTFArgTypes.size())
+      return false;
+
+    auto RTFTyIt = RTFArgTypes.begin();
+    for (Argument &Arg : F->args()) {
+      if (Arg.getType() != *RTFTyIt)
+        return false;
+
+      ++RTFTyIt;
+    }
+
+    return true;
+  }
+
+  /// Helper to initialize all runtime function information for those defined
+  /// in OpenMPKinds.def.
+  void initializeRuntimeFunctions() {
+    // Helper to collect all uses of the decleration in the UsesMap.
+    auto CollectUses = [&](RuntimeFunctionInfo &RFI) {
+      unsigned NumUses = 0;
+      if (!RFI.Declaration)
+        return NumUses;
+      OMPBuilder.addAttributes(RFI.Kind, *RFI.Declaration);
+
+      NumOpenMPRuntimeFunctionsIdentified += 1;
+      NumOpenMPRuntimeFunctionUsesIdentified += RFI.Declaration->getNumUses();
+
+      // TODO: We directly convert uses into proper calls and unknown uses.
+      for (Use &U : RFI.Declaration->uses()) {
+        if (Instruction *UserI = dyn_cast<Instruction>(U.getUser())) {
+          if (ModuleSlice.count(UserI->getFunction())) {
+            RFI.getOrCreateUseVector(UserI->getFunction()).push_back(&U);
+            ++NumUses;
+          }
+        } else {
+          RFI.getOrCreateUseVector(nullptr).push_back(&U);
+          ++NumUses;
+        }
+      }
+      return NumUses;
+    };
+
+    Module &M = *((*ModuleSlice.begin())->getParent());
+
+#define OMP_RTL(_Enum, _Name, _IsVarArg, _ReturnType, ...)                     \
+  {                                                                            \
+    SmallVector<Type *, 8> ArgsTypes({__VA_ARGS__});                           \
+    Function *F = M.getFunction(_Name);                                        \
+    if (declMatchesRTFTypes(F, _ReturnType, ArgsTypes)) {                      \
+      auto &RFI = RFIs[_Enum];                                                 \
+      RFI.Kind = _Enum;                                                        \
+      RFI.Name = _Name;                                                        \
+      RFI.IsVarArg = _IsVarArg;                                                \
+      RFI.ReturnType = _ReturnType;                                            \
+      RFI.ArgumentTypes = std::move(ArgsTypes);                                \
+      RFI.Declaration = F;                                                     \
+      unsigned NumUses = CollectUses(RFI);                                     \
+      (void)NumUses;                                                           \
+      LLVM_DEBUG({                                                             \
+        dbgs() << TAG << RFI.Name << (RFI.Declaration ? "" : " not")           \
+               << " found\n";                                                  \
+        if (RFI.Declaration)                                                   \
+          dbgs() << TAG << "-> got " << NumUses << " uses in "                 \
+                 << RFI.getNumFunctionsWithUses()                              \
+                 << " different functions.\n";                                 \
+      });                                                                      \
+    }                                                                          \
+  }
+#include "llvm/Frontend/OpenMP/OMPKinds.def"
+
+    // TODO: We should attach the attributes defined in OMPKinds.def.
+  }
+};
+
+struct OpenMPOpt {
+
+  using OptimizationRemarkGetter =
+      function_ref<OptimizationRemarkEmitter &(Function *)>;
+
+  OpenMPOpt(SmallVectorImpl<Function *> &SCC, CallGraphUpdater &CGUpdater,
+            OptimizationRemarkGetter OREGetter,
+            OMPInformationCache *OMPInfoCache)
+      : M(*(*SCC.begin())->getParent()), SCC(SCC),
+        ModuleSlice(OMPInfoCache->ModuleSlice), CGUpdater(CGUpdater),
+        OREGetter(OREGetter), OMPInfoCache(OMPInfoCache) {}
+
   /// Run all OpenMP optimizations on the underlying SCC/ModuleSlice.
   bool run() {
     bool Changed = false;
 
     LLVM_DEBUG(dbgs() << TAG << "Run on SCC with " << SCC.size()
                       << " functions in a slice with " << ModuleSlice.size()
                       << " functions\n");
 
     Changed |= deduplicateRuntimeCalls();
     Changed |= deleteParallelRegions();
 
     return Changed;
   }
 
+  /// Return the call if \p U is a callee use in a regular call. If \p RFI is
+  /// given it has to be the callee or a nullptr is returned.
+  static CallInst *getCallIfRegularCall(
+      Use &U, OMPInformationCache::RuntimeFunctionInfo *RFI = nullptr) {
+    CallInst *CI = dyn_cast<CallInst>(U.getUser());
+    if (CI && CI->isCallee(&U) && !CI->hasOperandBundles() &&
+        (!RFI || CI->getCalledFunction() == RFI->Declaration))
+      return CI;
+    return nullptr;
+  }
+
+  /// Return the call if \p V is a regular call. If \p RFI is given it has to be
+  /// the callee or a nullptr is returned.
+  static CallInst *getCallIfRegularCall(
+      Value &V, OMPInformationCache::RuntimeFunctionInfo *RFI = nullptr) {
+    CallInst *CI = dyn_cast<CallInst>(&V);
+    if (CI && !CI->hasOperandBundles() &&
+        (!RFI || CI->getCalledFunction() == RFI->Declaration))
+      return CI;
+    return nullptr;
+  }
+
 private:
   /// Try to delete parallel regions if possible.
   bool deleteParallelRegions() {
     const unsigned CallbackCalleeOperand = 2;
 
-    RuntimeFunctionInfo &RFI = RFIs[OMPRTL___kmpc_fork_call];
+    OMPInformationCache::RuntimeFunctionInfo &RFI =
+        OMPInfoCache->RFIs[OMPRTL___kmpc_fork_call];
+
     if (!RFI.Declaration)
       return false;
 
     bool Changed = false;
     auto DeleteCallCB = [&](Use &U, Function &) {
       CallInst *CI = getCallIfRegularCall(U);
       if (!CI)
         return false;
bool deduplicateRuntimeCalls() {
     // Global-tid is handled separately.
     SmallSetVector<Value *, 16> GTIdArgs;
     collectGlobalThreadIdArguments(GTIdArgs);
     LLVM_DEBUG(dbgs() << TAG << "Found " << GTIdArgs.size()
                       << " global thread ID arguments\n");
 
     for (Function *F : SCC) {
       for (auto DeduplicableRuntimeCallID : DeduplicableRuntimeCallIDs)
-        deduplicateRuntimeCalls(*F, RFIs[DeduplicableRuntimeCallID]);
+        deduplicateRuntimeCalls(*F,
+                                OMPInfoCache->RFIs[DeduplicableRuntimeCallID]);
 
       // __kmpc_global_thread_num is special as we can replace it with an
       // argument in enough cases to make it worth trying.
       Value *GTIdArg = nullptr;
       for (Argument &Arg : F->args())
         if (GTIdArgs.count(&Arg)) {
           GTIdArg = &Arg;
           break;
         }
       Changed |= deduplicateRuntimeCalls(
-          *F, RFIs[OMPRTL___kmpc_global_thread_num], GTIdArg);
+          *F, OMPInfoCache->RFIs[OMPRTL___kmpc_global_thread_num], GTIdArg);
     }
 
     return Changed;
   }
 
   static Value *combinedIdentStruct(Value *CurrentIdent, Value *NextIdent,
                                     bool GlobalOnly, bool &SingleChoice) {
     if (CurrentIdent == NextIdent)
       return CurrentIdent;
 
     // TODO: Figure out how to actually combine multiple debug locations. For
     //       now we just keep an existing one if there is a single choice.
     if (!GlobalOnly || isa<GlobalValue>(NextIdent)) {
       SingleChoice = !CurrentIdent;
       return NextIdent;
     }
     return nullptr;
   }
 
   /// Return an `struct ident_t*` value that represents the ones used in the
   /// calls of \p RFI inside of \p F. If \p GlobalOnly is true, we will not
   /// return a local `struct ident_t*`. For now, if we cannot find a suitable
   /// return value we create one from scratch. We also do not yet combine
   /// information, e.g., the source locations, see combinedIdentStruct.
-  Value *getCombinedIdentFromCallUsesIn(RuntimeFunctionInfo &RFI, Function &F,
-                                        bool GlobalOnly) {
+  Value *
+  getCombinedIdentFromCallUsesIn(OMPInformationCache::RuntimeFunctionInfo &RFI,
+                                 Function &F, bool GlobalOnly) {
     bool SingleChoice = true;
     Value *Ident = nullptr;
     auto CombineIdentStruct = [&](Use &U, Function &Caller) {
       CallInst *CI = getCallIfRegularCall(U, &RFI);
       if (!CI || &F != &Caller)
         return false;
       Ident = combinedIdentStruct(Ident, CI->getArgOperand(0),
                                   /* GlobalOnly */ true, SingleChoice);
       return false;
     };
     RFI.foreachUse(CombineIdentStruct);
 
     if (!Ident || !SingleChoice) {
       // The IRBuilder uses the insertion block to get to the module, this is
       // unfortunate but we work around it for now.
-      if (!OMPBuilder.getInsertionPoint().getBlock())
-        OMPBuilder.updateToLocation(OpenMPIRBuilder::InsertPointTy(
-            &F.getEntryBlock(), F.getEntryBlock().begin()));
+      if (!OMPInfoCache->OMPBuilder.getInsertionPoint().getBlock())
+        OMPInfoCache->OMPBuilder.updateToLocation(
+            OpenMPIRBuilder::InsertPointTy(&F.getEntryBlock(),
+                                           F.getEntryBlock().begin()));
       // Create a fallback location if non was found.
       // TODO: Use the debug locations of the calls instead.
-      Constant *Loc = OMPBuilder.getOrCreateDefaultSrcLocStr();
-      Ident = OMPBuilder.getOrCreateIdent(Loc);
+      Constant *Loc = OMPInfoCache->OMPBuilder.getOrCreateDefaultSrcLocStr();
+      Ident = OMPInfoCache->OMPBuilder.getOrCreateIdent(Loc);
     }
     return Ident;
   }
 
   /// Try to eliminiate calls of \p RFI in \p F by reusing an existing one or
   /// \p ReplVal if given.
-  bool deduplicateRuntimeCalls(Function &F, RuntimeFunctionInfo &RFI,
+  bool deduplicateRuntimeCalls(Function &F,
+                               OMPInformationCache::RuntimeFunctionInfo &RFI,
                                Value *ReplVal = nullptr) {
     auto *UV = RFI.getUseVector(F);
     if (!UV || UV->size() + (ReplVal != nullptr) < 2)
       return false;
 
-    LLVM_DEBUG(dbgs() << TAG << "Deduplicate " << UV->size() << " uses of "
-                      << RFI.Name
-                      << (ReplVal ? " with an existing value\n" : "\n")
-                      << "\n");
+    LLVM_DEBUG(
+        dbgs() << TAG << "Deduplicate " << UV->size() << " uses of " << RFI.Name
+               << (ReplVal ? " with an existing value\n" : "\n") << "\n");
+
     assert((!ReplVal || (isa<Argument>(ReplVal) &&
                          cast<Argument>(ReplVal)->getParent() == &F)) &&
            "Unexpected replacement value!");
 
     // TODO: Use dominance to find a good position instead.
     auto CanBeMoved = [](CallBase &CB) {
       unsigned NumArgs = CB.getNumArgOperands();
       if (NumArgs == 0)
void collectGlobalThreadIdArguments(SmallSetVector<Value *, 16> &GTIdArgs) {
     // a GTId.
     auto CallArgOpIsGTId = [&](Function &F, unsigned ArgNo, CallInst &RefCI) {
       if (!F.hasLocalLinkage())
         return false;
       for (Use &U : F.uses()) {
         if (CallInst *CI = getCallIfRegularCall(U)) {
           Value *ArgOp = CI->getArgOperand(ArgNo);
           if (CI == &RefCI || GTIdArgs.count(ArgOp) ||
-              getCallIfRegularCall(*ArgOp,
-                                   &RFIs[OMPRTL___kmpc_global_thread_num]))
+              getCallIfRegularCall(
+                  *ArgOp, &OMPInfoCache->RFIs[OMPRTL___kmpc_global_thread_num]))
             continue;
         }
         return false;
       }
       return true;
     };
 
     // Helper to identify uses of a GTId as GTId arguments.
     auto AddUserArgs = [&](Value &GTId) {
       for (Use &U : GTId.uses())
         if (CallInst *CI = dyn_cast<CallInst>(U.getUser()))
           if (CI->isArgOperand(&U))
             if (Function *Callee = CI->getCalledFunction())
               if (CallArgOpIsGTId(*Callee, U.getOperandNo(), *CI))
                 GTIdArgs.insert(Callee->getArg(U.getOperandNo()));
     };
 
     // The argument users of __kmpc_global_thread_num calls are GTIds.
-    RuntimeFunctionInfo &GlobThreadNumRFI =
-        RFIs[OMPRTL___kmpc_global_thread_num];
+    OMPInformationCache::RuntimeFunctionInfo &GlobThreadNumRFI =
+        OMPInfoCache->RFIs[OMPRTL___kmpc_global_thread_num];
+
     GlobThreadNumRFI.foreachUse([&](Use &U, Function &F) {
       if (CallInst *CI = getCallIfRegularCall(U, &GlobThreadNumRFI))
         AddUserArgs(*CI);
       return false;
     });
 
     // Transitively search for more arguments by looking at the users of the
     // ones we know already. During the search the GTIdArgs vector is extended
     // so we cannot cache the size nor can we use a range based for.
     for (unsigned u = 0; u < GTIdArgs.size(); ++u)
       AddUserArgs(*GTIdArgs[u]);
   }
 
-  /// Return the call if \p U is a callee use in a regular call. If \p RFI is
-  /// given it has to be the callee or a nullptr is returned.
-  CallInst *getCallIfRegularCall(Use &U, RuntimeFunctionInfo *RFI = nullptr) {
-    CallInst *CI = dyn_cast<CallInst>(U.getUser());
-    if (CI && CI->isCallee(&U) && !CI->hasOperandBundles() &&
-        (!RFI || CI->getCalledFunction() == RFI->Declaration))
-      return CI;
-    return nullptr;
-  }
-
-  /// Return the call if \p V is a regular call. If \p RFI is given it has to be
-  /// the callee or a nullptr is returned.
-  CallInst *getCallIfRegularCall(Value &V, RuntimeFunctionInfo *RFI = nullptr) {
-    CallInst *CI = dyn_cast<CallInst>(&V);
-    if (CI && !CI->hasOperandBundles() &&
-        (!RFI || CI->getCalledFunction() == RFI->Declaration))
-      return CI;
-    return nullptr;
-  }
-
-  /// Returns true if the function declaration \p F matches the runtime
-  /// function types, that is, return type \p RTFRetType, and argument types
-  /// \p RTFArgTypes.
-  static bool declMatchesRTFTypes(Function *F, Type *RTFRetType,
-                                  SmallVector<Type *, 8> &RTFArgTypes) {
-    // TODO: We should output information to the user (under debug output
-    //       and via remarks).
-
-    if (!F)
-      return false;
-    if (F->getReturnType() != RTFRetType)
-      return false;
-    if (F->arg_size() != RTFArgTypes.size())
-      return false;
-
-    auto RTFTyIt = RTFArgTypes.begin();
-    for (Argument &Arg : F->args()) {
-      if (Arg.getType() != *RTFTyIt)
-        return false;
-
-      ++RTFTyIt;
-    }
-
-    return true;
-  }
-
-  /// Helper to initialize all runtime function information for those defined in
-  /// OpenMPKinds.def.
-  void initializeRuntimeFunctions() {
-    // Helper to collect all uses of the decleration in the UsesMap.
-    auto CollectUses = [&](RuntimeFunctionInfo &RFI) {
-      unsigned NumUses = 0;
-      if (!RFI.Declaration)
-        return NumUses;
-      OMPBuilder.addAttributes(RFI.Kind, *RFI.Declaration);
-
-      NumOpenMPRuntimeFunctionsIdentified += 1;
-      NumOpenMPRuntimeFunctionUsesIdentified += RFI.Declaration->getNumUses();
-
-      // TODO: We directly convert uses into proper calls and unknown uses.
-      for (Use &U : RFI.Declaration->uses()) {
-        if (Instruction *UserI = dyn_cast<Instruction>(U.getUser())) {
-          if (ModuleSlice.count(UserI->getFunction())) {
-            RFI.getOrCreateUseVector(UserI->getFunction()).push_back(&U);
-            ++NumUses;
-          }
-        } else {
-          RFI.getOrCreateUseVector(nullptr).push_back(&U);
-          ++NumUses;
-        }
-      }
-      return NumUses;
-    };
-
-#define OMP_RTL(_Enum, _Name, _IsVarArg, _ReturnType, ...)                     \
-  {                                                                            \
-    SmallVector<Type *, 8> ArgsTypes({__VA_ARGS__});                           \
-    Function *F = M.getFunction(_Name);                                        \
-    if (declMatchesRTFTypes(F, _ReturnType, ArgsTypes)) {                      \
-      auto &RFI = RFIs[_Enum];                                                 \
-      RFI.Kind = _Enum;                                                        \
-      RFI.Name = _Name;                                                        \
-      RFI.IsVarArg = _IsVarArg;                                                \
-      RFI.ReturnType = _ReturnType;                                            \
-      RFI.ArgumentTypes = std::move(ArgsTypes);                                \
-      RFI.Declaration = F;                                                     \
-      unsigned NumUses = CollectUses(RFI);                                     \
-      (void)NumUses;                                                           \
-      LLVM_DEBUG({                                                             \
-        dbgs() << TAG << RFI.Name << (RFI.Declaration ? "" : " not")           \
-               << " found\n";                                                  \
-        if (RFI.Declaration)                                                   \
-          dbgs() << TAG << "-> got " << NumUses << " uses in "                 \
-                 << RFI.getNumFunctionsWithUses()                              \
-                 << " different functions.\n";                                 \
-      });                                                                      \
-    }                                                                          \
-  }
-#include "llvm/Frontend/OpenMP/OMPKinds.def"
-
-    // TODO: We should attach the attributes defined in OMPKinds.def.
-  }
-
   /// Emit a remark generically
   ///
   /// This template function can be used to generically emit a remark. The
   /// RemarkKind should be one of the following:
   ///   - OptimizationRemark to indicate a successful optimization attempt
   ///   - OptimizationRemarkMissed to report a failed optimization attempt
   ///   - OptimizationRemarkAnalysis to provide additional information about an
   ///     optimization attempt
   ///
   /// The remark is built using a callback function provided by the caller that
   /// takes a RemarkKind as input and returns a RemarkKind.
   template <typename RemarkKind,
             typename RemarkCallBack = function_ref<RemarkKind(RemarkKind &&)>>
   void emitRemark(Instruction *Inst, StringRef RemarkName,
                   RemarkCallBack &&RemarkCB) {
     Function *F = Inst->getParent()->getParent();
     auto &ORE = OREGetter(F);
 
-    ORE.emit([&]() {
-      return RemarkCB(RemarkKind(DEBUG_TYPE, RemarkName, Inst));
-    });
+    ORE.emit(
+        [&]() { return RemarkCB(RemarkKind(DEBUG_TYPE, RemarkName, Inst)); });
   }
 
   /// The underyling module.
   Module &M;
 
   /// The SCC we are operating on.
   SmallVectorImpl<Function *> &SCC;
 
   /// The slice of the module we are allowed to look at.
   SmallPtrSetImpl<Function *> &ModuleSlice;
 
-  /// An OpenMP-IR-Builder instance
-  OpenMPIRBuilder OMPBuilder;
-
   /// Callback to update the call graph, the first argument is a removed call,
   /// the second an optional replacement call.
   CallGraphUpdater &CGUpdater;
 
   /// Callback to get an OptimizationRemarkEmitter from a Function *
   OptimizationRemarkGetter OREGetter;
 
-  /// Map from runtime function kind to the runtime function description.
-  EnumeratedArray<RuntimeFunctionInfo, RuntimeFunction,
-                  RuntimeFunction::OMPRTL___last>
-      RFIs;
+  /// OpenMP-specific information cache. Also Used for Attributor runs.
+  OMPInformationCache *OMPInfoCache;
 };
 } // namespace
 
 PreservedAnalyses OpenMPOptPass::run(LazyCallGraph::SCC &C,
                                      CGSCCAnalysisManager &AM,
                                      LazyCallGraph &CG, CGSCCUpdateResult &UR) {
   if (!containsOpenMP(*C.begin()->getFunction().getParent(), OMPInModule))
     return PreservedAnalyses::all();
 
   if (DisableOpenMPOptimizations)
     return PreservedAnalyses::all();
 
   SmallPtrSet<Function *, 16> ModuleSlice;
   SmallVector<Function *, 16> SCC;
   for (LazyCallGraph::Node &N : C) {
     SCC.push_back(&N.getFunction());
     ModuleSlice.insert(SCC.back());
   }
 
   if (SCC.empty())
     return PreservedAnalyses::all();
 
-  auto OREGetter = [&C, &CG, &AM](Function *F) -> OptimizationRemarkEmitter & {
-    FunctionAnalysisManager &FAM =
-        AM.getResult<FunctionAnalysisManagerCGSCCProxy>(C, CG).getManager();
+
+  AnalysisGetter AG(FAM);
+
+  auto OREGetter = [&FAM](Function *F) -> OptimizationRemarkEmitter & {
     return FAM.getResult<OptimizationRemarkEmitterAnalysis>(*F);
   };
 
   CallGraphUpdater CGUpdater;
   CGUpdater.initialize(CG, C, AM, UR);
+
+  SetVector<Function *> Functions(SCC.begin(), SCC.end());
+  BumpPtrAllocator Allocator;
+  OMPInformationCache InfoCache(*(Functions.back()->getParent()), AG, Allocator,
+                                /*CGSCC*/ &Functions, ModuleSlice);
+
   // TODO: Compute the module slice we are allowed to look at.
-  OpenMPOpt OMPOpt(SCC, ModuleSlice, CGUpdater, OREGetter);
+  OpenMPOpt OMPOpt(SCC, CGUpdater, OREGetter, &InfoCache);
   bool Changed = OMPOpt.run();
   (void)Changed;
   return PreservedAnalyses::all();
 }
 
 namespace {
 
 struct OpenMPOptLegacyPass : public CallGraphSCCPass {
bool runOnSCC(CallGraphSCC &CGSCC) override {
     DenseMap<Function *, std::unique_ptr<OptimizationRemarkEmitter>> OREMap;
     auto OREGetter = [&OREMap](Function *F) -> OptimizationRemarkEmitter & {
       std::unique_ptr<OptimizationRemarkEmitter> &ORE = OREMap[F];
       if (!ORE)
         ORE = std::make_unique<OptimizationRemarkEmitter>(F);
       return *ORE;
     };
 
+    AnalysisGetter AG;
+    SetVector<Function *> Functions(SCC.begin(), SCC.end());
+    BumpPtrAllocator Allocator;
+    OMPInformationCache InfoCache(*(Functions.back()->getParent()), AG,
+                                  Allocator,
+                                  /*CGSCC*/ &Functions, ModuleSlice);
+
     // TODO: Compute the module slice we are allowed to look at.
-    OpenMPOpt OMPOpt(SCC, ModuleSlice, CGUpdater, OREGetter);
+    OpenMPOpt OMPOpt(SCC, CGUpdater, OREGetter, &InfoCache);
     return OMPOpt.run();
   }
 
   bool doFinalization(CallGraph &CG) override { return CGUpdater.finalize(); }
 };
 
 } // end anonymous namespace