Index: llvm/trunk/include/llvm/Transforms/IPO/Attributor.h
===================================================================
--- llvm/trunk/include/llvm/Transforms/IPO/Attributor.h
+++ llvm/trunk/include/llvm/Transforms/IPO/Attributor.h
@@ -568,7 +568,15 @@
 /// NOTE: The mechanics of adding a new "concrete" abstract attribute are
 ///       described in the file comment.
 struct Attributor {
-  Attributor(InformationCache &InfoCache) : InfoCache(InfoCache) {}
+  /// Constructor
+  ///
+  /// \param InformationCache Cache to hold various information accessible for
+  ///                         the abstract attributes.
+  /// \param DepRecomputeInterval Number of iterations until the dependences
+  ///                             between abstract attributes are recomputed.
+  Attributor(InformationCache &InfoCache, unsigned DepRecomputeInterval)
+      : InfoCache(InfoCache), DepRecomputeInterval(DepRecomputeInterval) {}
+
   ~Attributor() { DeleteContainerPointers(AllAbstractAttributes); }
 
   /// Run the analyses until a fixpoint is reached or enforced (timeout).
@@ -775,6 +783,10 @@
   /// The information cache that holds pre-processed (LLVM-IR) information.
   InformationCache &InfoCache;
 
+  /// Number of iterations until the dependences between abstract attributes are
+  /// recomputed.
+  const unsigned DepRecomputeInterval;
+
   /// Functions, blocks, and instructions we delete after manifest is done.
   ///
   ///{
Index: llvm/trunk/lib/Transforms/IPO/Attributor.cpp
===================================================================
--- llvm/trunk/lib/Transforms/IPO/Attributor.cpp
+++ llvm/trunk/lib/Transforms/IPO/Attributor.cpp
@@ -123,6 +123,11 @@
              "manifestation of attributes -- may issue false-positive errors"),
     cl::init(false));
 
+static cl::opt<unsigned> DepRecInterval(
+    "attributor-dependence-recompute-interval", cl::Hidden,
+    cl::desc("Number of iterations until dependences are recomputed."),
+    cl::init(4));
+
 /// Logic operators for the change status enum class.
 ///
 ///{
@@ -2548,12 +2553,25 @@
   SetVector<AbstractAttribute *> Worklist;
   Worklist.insert(AllAbstractAttributes.begin(), AllAbstractAttributes.end());
 
+  bool RecomputeDependences = false;
+
   do {
     // Remember the size to determine new attributes.
     size_t NumAAs = AllAbstractAttributes.size();
     LLVM_DEBUG(dbgs() << "\n\n[Attributor] #Iteration: " << IterationCounter
                       << ", Worklist size: " << Worklist.size() << "\n");
 
+    // If dependences (=QueryMap) are recomputed we have to look at all abstract
+    // attributes again, regardless of what changed in the last iteration.
+    if (RecomputeDependences) {
+      LLVM_DEBUG(
+          dbgs() << "[Attributor] Run all AAs to recompute dependences\n");
+      QueryMap.clear();
+      ChangedAAs.clear();
+      Worklist.insert(AllAbstractAttributes.begin(),
+                      AllAbstractAttributes.end());
+    }
+
     // Add all abstract attributes that are potentially dependent on one that
     // changed to the work list.
     for (AbstractAttribute *ChangedAA : ChangedAAs) {
@@ -2575,6 +2593,10 @@
         if (AA->update(*this) == ChangeStatus::CHANGED)
           ChangedAAs.push_back(AA);
 
+    // Check if we recompute the dependences in the next iteration.
+    RecomputeDependences = (DepRecomputeInterval > 0 &&
+                            IterationCounter % DepRecomputeInterval == 0);
+
     // Add attributes to the changed set if they have been created in the last
     // iteration.
     ChangedAAs.append(AllAbstractAttributes.begin() + NumAAs,
@@ -2589,13 +2611,18 @@
 
   size_t NumFinalAAs = AllAbstractAttributes.size();
 
+  if (VerifyMaxFixpointIterations && IterationCounter != MaxFixpointIterations) {
+    errs() << "\n[Attributor] Fixpoint iteration done after: "
+           << IterationCounter << "/" << MaxFixpointIterations
+           << " iterations\n";
+    llvm_unreachable("The fixpoint was not reached with exactly the number of "
+                     "specified iterations!");
+  }
+
   LLVM_DEBUG(dbgs() << "\n[Attributor] Fixpoint iteration done after: "
                     << IterationCounter << "/" << MaxFixpointIterations
                     << " iterations\n");
 
-  if (VerifyMaxFixpointIterations && IterationCounter != MaxFixpointIterations)
-    llvm_unreachable("The fixpoint was not reached with exactly the number of "
-                     "specified iterations!");
 
   bool FinishedAtFixpoint = Worklist.empty();
 
@@ -2930,7 +2957,7 @@
   // Create an Attributor and initially empty information cache that is filled
   // while we identify default attribute opportunities.
   InformationCache InfoCache(M.getDataLayout());
-  Attributor A(InfoCache);
+  Attributor A(InfoCache, DepRecInterval);
 
   for (Function &F : M) {
     // TODO: Not all attributes require an exact definition. Find a way to
Index: llvm/trunk/test/Transforms/FunctionAttrs/align.ll
===================================================================
--- llvm/trunk/test/Transforms/FunctionAttrs/align.ll
+++ llvm/trunk/test/Transforms/FunctionAttrs/align.ll
@@ -1,4 +1,4 @@
-; RUN: opt -attributor -attributor-disable=false -attributor-max-iterations-verify -attributor-max-iterations=15 -S < %s | FileCheck %s --check-prefix=ATTRIBUTOR
+; RUN: opt -attributor -attributor-disable=false -attributor-max-iterations-verify -attributor-max-iterations=14 -S < %s | FileCheck %s --check-prefix=ATTRIBUTOR
 
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 
Index: llvm/trunk/test/Transforms/FunctionAttrs/nonnull.ll
===================================================================
--- llvm/trunk/test/Transforms/FunctionAttrs/nonnull.ll
+++ llvm/trunk/test/Transforms/FunctionAttrs/nonnull.ll
@@ -1,6 +1,6 @@
 ; RUN: opt -S -functionattrs -enable-nonnull-arg-prop %s | FileCheck %s --check-prefixes=BOTH,FNATTR
 ; RUN: opt -S -passes=function-attrs -enable-nonnull-arg-prop %s | FileCheck %s --check-prefixes=BOTH,FNATTR
-; RUN: opt -attributor --attributor-disable=false -attributor-max-iterations-verify -attributor-max-iterations=11 -S < %s | FileCheck %s --check-prefixes=BOTH,ATTRIBUTOR
+; RUN: opt -attributor --attributor-disable=false -attributor-max-iterations-verify -attributor-max-iterations=10 -S < %s | FileCheck %s --check-prefixes=BOTH,ATTRIBUTOR
 
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 
Index: llvm/trunk/test/Transforms/FunctionAttrs/noreturn_sync.ll
===================================================================
--- llvm/trunk/test/Transforms/FunctionAttrs/noreturn_sync.ll
+++ llvm/trunk/test/Transforms/FunctionAttrs/noreturn_sync.ll
@@ -1,4 +1,4 @@
-; RUN: opt -functionattrs -attributor -attributor-disable=false -attributor-max-iterations-verify -attributor-max-iterations=7 -S < %s | FileCheck %s
+; RUN: opt -functionattrs -attributor -attributor-disable=false -attributor-max-iterations-verify -attributor-max-iterations=6 -S < %s | FileCheck %s
 ;
 ; This file is the same as noreturn_async.ll but with a personality which
 ; indicates that the exception handler *cannot* catch asynchronous exceptions.