Commit 214ed3f6 authored by Johannes Doerfert's avatar Johannes Doerfert
Browse files

[Attributor] Record dependences only when necessary 

If we use assumed information from AAValueSimplify we need to record
an OPTIONAL dependence, otherwise we do not.
parent 5429c82d

llvm/lib/Transforms/IPO/Attributor.cpp

+22 −14
Original line number Diff line number Diff line
@@ -255,6 +255,28 @@ static void replaceAllInstructionUsesWith(Value &Old, Value &New) { 
    U->set(&New);

}



static Optional<ConstantInt *>

getAssumedConstant(Attributor &A, const Value &V, const AbstractAttribute &AA,

                   bool &UsedAssumedInformation) {

  const auto &ValueSimplifyAA = A.getAAFor<AAValueSimplify>(

      AA, IRPosition::value(V), /* TrackDependence */ false);

  Optional<Value *> SimplifiedV = ValueSimplifyAA.getAssumedSimplifiedValue(A);

  bool IsKnown = ValueSimplifyAA.isKnown();

  UsedAssumedInformation |= !IsKnown;

  if (!SimplifiedV.hasValue()) {

    A.recordDependence(ValueSimplifyAA, AA, DepClassTy::OPTIONAL);

    return llvm::None;

  }

  if (isa_and_nonnull<UndefValue>(SimplifiedV.getValue())) {

    A.recordDependence(ValueSimplifyAA, AA, DepClassTy::OPTIONAL);

    return llvm::None;

  }

  ConstantInt *CI = dyn_cast_or_null<ConstantInt>(SimplifiedV.getValue());

  if (CI)

    A.recordDependence(ValueSimplifyAA, AA, DepClassTy::OPTIONAL);

  return CI;

}



/// Recursively visit all values that might become \p IRP at some point. This

/// will be done by looking through cast instructions, selects, phis, and calls

/// with the "returned" attribute. Once we cannot look through the value any
@@ -2980,20 +3002,6 @@ identifyAliveSuccessors(Attributor &A, const InvokeInst &II, 
  return UsedAssumedInformation;

}



static Optional<ConstantInt *>

getAssumedConstant(Attributor &A, const Value &V, AbstractAttribute &AA,

                   bool &UsedAssumedInformation) {

  const auto &ValueSimplifyAA =

      A.getAAFor<AAValueSimplify>(AA, IRPosition::value(V));

  Optional<Value *> SimplifiedV = ValueSimplifyAA.getAssumedSimplifiedValue(A);

  UsedAssumedInformation |= !ValueSimplifyAA.isKnown();

  if (!SimplifiedV.hasValue())

    return llvm::None;

  if (isa_and_nonnull<UndefValue>(SimplifiedV.getValue()))

    return llvm::None;

  return dyn_cast_or_null<ConstantInt>(SimplifiedV.getValue());

}



static bool

identifyAliveSuccessors(Attributor &A, const BranchInst &BI,

                        AbstractAttribute &AA,