Reapply "[Attributor] Disable simplification AAs if a callback is present""

This reapplies commit cbb709e and
includes the use of the lookup method instead of operator[] to avoid
accidentally setting (empty) simplification callbacks.

This reverts commit aa27430.

Author: jdoerfert

llvm/include/llvm/Transforms/IPO/Attributor.h

@@ -1563,6 +1563,11 @@ struct Attributor {
     SimplificationCallbacks[IRP].emplace_back(CB);
   }
 
+  /// Return true if there is a simplification callback for \p IRP.
+  bool hasSimplificationCallback(const IRPosition &IRP) {
+    return SimplificationCallbacks.count(IRP);
+  }
+
 private:
   /// The vector with all simplification callbacks registered by outside AAs.
   DenseMap<IRPosition, SmallVector<SimplifictionCallbackTy, 1>>

llvm/lib/Transforms/IPO/Attributor.cpp

@@ -761,7 +761,7 @@ Attributor::getAssumedConstant(const IRPosition &IRP,
   // First check all callbacks provided by outside AAs. If any of them returns
   // a non-null value that is different from the associated value, or None, we
   // assume it's simpliied.
-  for (auto &CB : SimplificationCallbacks[IRP]) {
+  for (auto &CB : SimplificationCallbacks.lookup(IRP)) {
     Optional<Value *> SimplifiedV = CB(IRP, &AA, UsedAssumedInformation);
     if (!SimplifiedV.hasValue())
       return llvm::None;
@@ -799,7 +799,7 @@ Attributor::getAssumedSimplified(const IRPosition &IRP,
   // First check all callbacks provided by outside AAs. If any of them returns
   // a non-null value that is different from the associated value, or None, we
   // assume it's simpliied.
-  for (auto &CB : SimplificationCallbacks[IRP])
+  for (auto &CB : SimplificationCallbacks.lookup(IRP))
     return CB(IRP, AA, UsedAssumedInformation);
 
   // If no high-level/outside simplification occured, use AAValueSimplify.

llvm/lib/Transforms/IPO/AttributorAttributes.cpp

@@ -5067,6 +5067,8 @@ struct AAValueSimplifyImpl : AAValueSimplify {
   void initialize(Attributor &A) override {
     if (getAssociatedValue().getType()->isVoidTy())
       indicatePessimisticFixpoint();
+    if (A.hasSimplificationCallback(getIRPosition()))
+      indicatePessimisticFixpoint();
   }
 
   /// See AbstractAttribute::getAsStr().
@@ -5400,9 +5402,7 @@ struct AAValueSimplifyFloating : AAValueSimplifyImpl {
 
   /// See AbstractAttribute::initialize(...).
   void initialize(Attributor &A) override {
-    // FIXME: This might have exposed a SCC iterator update bug in the old PM.
-    //        Needs investigation.
-    // AAValueSimplifyImpl::initialize(A);
+    AAValueSimplifyImpl::initialize(A);
     Value &V = getAnchorValue();
 
     // TODO: add other stuffs
@@ -5639,6 +5639,7 @@ struct AAValueSimplifyCallSiteReturned : AAValueSimplifyImpl {
       : AAValueSimplifyImpl(IRP, A) {}
 
   void initialize(Attributor &A) override {
+    AAValueSimplifyImpl::initialize(A);
     if (!getAssociatedFunction())
       indicatePessimisticFixpoint();
   }
@@ -7888,6 +7889,20 @@ struct AAValueConstantRangeImpl : AAValueConstantRange {
   AAValueConstantRangeImpl(const IRPosition &IRP, Attributor &A)
       : AAValueConstantRange(IRP, A) {}
 
+  /// See AbstractAttribute::initialize(..).
+  void initialize(Attributor &A) override {
+    if (A.hasSimplificationCallback(getIRPosition())) {
+      indicatePessimisticFixpoint();
+      return;
+    }
+
+    // Intersect a range given by SCEV.
+    intersectKnown(getConstantRangeFromSCEV(A, getCtxI()));
+
+    // Intersect a range given by LVI.
+    intersectKnown(getConstantRangeFromLVI(A, getCtxI()));
+  }
+
   /// See AbstractAttribute::getAsStr().
   const std::string getAsStr() const override {
     std::string Str;
@@ -8019,15 +8034,6 @@ struct AAValueConstantRangeImpl : AAValueConstantRange {
     return getAssumed().intersectWith(SCEVR).intersectWith(LVIR);
   }
 
-  /// See AbstractAttribute::initialize(..).
-  void initialize(Attributor &A) override {
-    // Intersect a range given by SCEV.
-    intersectKnown(getConstantRangeFromSCEV(A, getCtxI()));
-
-    // Intersect a range given by LVI.
-    intersectKnown(getConstantRangeFromLVI(A, getCtxI()));
-  }
-
   /// Helper function to create MDNode for range metadata.
   static MDNode *
   getMDNodeForConstantRange(Type *Ty, LLVMContext &Ctx,
@@ -8157,6 +8163,9 @@ struct AAValueConstantRangeFloating : AAValueConstantRangeImpl {
   /// See AbstractAttribute::initialize(...).
   void initialize(Attributor &A) override {
     AAValueConstantRangeImpl::initialize(A);
+    if (isAtFixpoint())
+      return;
+
     Value &V = getAssociatedValue();
 
     if (auto *C = dyn_cast<ConstantInt>(&V)) {
@@ -8177,6 +8186,7 @@ struct AAValueConstantRangeFloating : AAValueConstantRangeImpl {
 
     if (isa<BinaryOperator>(&V) || isa<CmpInst>(&V) || isa<CastInst>(&V))
       return;
+
     // If it is a load instruction with range metadata, use it.
     if (LoadInst *LI = dyn_cast<LoadInst>(&V))
       if (auto *RangeMD = LI->getMetadata(LLVMContext::MD_range)) {
@@ -8504,6 +8514,14 @@ struct AAPotentialValuesImpl : AAPotentialValues {
   AAPotentialValuesImpl(const IRPosition &IRP, Attributor &A)
       : AAPotentialValues(IRP, A) {}
 
+  /// See AbstractAttribute::initialize(..).
+  void initialize(Attributor &A) override {
+    if (A.hasSimplificationCallback(getIRPosition()))
+      indicatePessimisticFixpoint();
+    else
+      AAPotentialValues::initialize(A);
+  }
+
   /// See AbstractAttribute::getAsStr().
   const std::string getAsStr() const override {
     std::string Str;
@@ -8561,6 +8579,10 @@ struct AAPotentialValuesFloating : AAPotentialValuesImpl {
 
   /// See AbstractAttribute::initialize(..).
   void initialize(Attributor &A) override {
+    AAPotentialValuesImpl::initialize(A);
+    if (isAtFixpoint())
+      return;
+
     Value &V = getAssociatedValue();
 
     if (auto *C = dyn_cast<ConstantInt>(&V)) {
@@ -9093,6 +9115,10 @@ struct AAPotentialValuesCallSiteArgument : AAPotentialValuesFloating {
 
   /// See AbstractAttribute::initialize(..).
   void initialize(Attributor &A) override {
+    AAPotentialValuesImpl::initialize(A);
+    if (isAtFixpoint())
+      return;
+
     Value &V = getAssociatedValue();
 
     if (auto *C = dyn_cast<ConstantInt>(&V)) {