Commit 0f4383fa authored by Hideto Ueno's avatar Hideto Ueno
Browse files

[Attributor] Handle special case when offset equals zero in nonnull deduction

parent cbfa2378

llvm/lib/Transforms/IPO/Attributor.cpp

+18 −6
Original line number Diff line number Diff line
@@ -308,15 +308,16 @@ static const Value *getPointerOperand(const Instruction *I) { 


  return nullptr;

}

static const Value *getBasePointerOfAccessPointerOperand(const Instruction *I,

                                                         int64_t &BytesOffset,

                                                         const DataLayout &DL) {

static const Value *

getBasePointerOfAccessPointerOperand(const Instruction *I, int64_t &BytesOffset,

                                     const DataLayout &DL,

                                     bool AllowNonInbounds = false) {

  const Value *Ptr = getPointerOperand(I);

  if (!Ptr)

    return nullptr;



  return GetPointerBaseWithConstantOffset(Ptr, BytesOffset, DL,

                                          /*AllowNonInbounds*/ false);

                                          AllowNonInbounds);

}



ChangeStatus AbstractAttribute::update(Attributor &A) {
@@ -1702,8 +1703,7 @@ static int64_t getKnownNonNullAndDerefBytesForUse( 
    return 0;

  }

  if (auto *GEP = dyn_cast<GetElementPtrInst>(I))

    if (GEP->hasAllZeroIndices() ||

        (GEP->isInBounds() && GEP->hasAllConstantIndices())) {

    if (GEP->hasAllConstantIndices()) {

      TrackUse = true;

      return 0;

    }
@@ -1718,6 +1718,18 @@ static int64_t getKnownNonNullAndDerefBytesForUse( 
      return std::max(int64_t(0), DerefBytes);

    }

  }



  /// Corner case when an offset is 0.

  if (const Value *Base = getBasePointerOfAccessPointerOperand(

          I, Offset, DL, /*AllowNonInbounds*/ true)) {

    if (Offset == 0 && Base == &AssociatedValue &&

        getPointerOperand(I) == UseV) {

      int64_t DerefBytes =

          (int64_t)DL.getTypeStoreSize(PtrTy->getPointerElementType());

      IsNonNull |= !NullPointerIsDefined;

      return std::max(int64_t(0), DerefBytes);

    }

  }

  if (const Value *Base =

          GetPointerBaseWithConstantOffset(UseV, Offset, DL,

                                           /*AllowNonInbounds*/ false)) {

llvm/test/Transforms/FunctionAttrs/align.ll

+2 −4
Original line number Diff line number Diff line
@@ -351,8 +351,7 @@ define i64 @test12-1(i32* align 4 %p) { 
  ret i64 %ret

}



; FXIME: %p should have nonnull

; ATTRIBUTOR: define i64 @test12-2(i32* nocapture nofree readonly align 16 %p)

; ATTRIBUTOR: define i64 @test12-2(i32* nocapture nofree nonnull readonly align 16 dereferenceable(8) %p)

define i64 @test12-2(i32* align 4 %p) {

  %p-cast = bitcast i32* %p to i64*

  %arrayidx0 = getelementptr i64, i64* %p-cast, i64 0
@@ -370,8 +369,7 @@ define void @test12-3(i32* align 4 %p) { 
  ret void 

}



; FXIME: %p should have nonnull

; ATTRIBUTOR: define void @test12-4(i32* nocapture nofree writeonly align 16 %p)

; ATTRIBUTOR: define void @test12-4(i32* nocapture nofree nonnull writeonly align 16 dereferenceable(8) %p)

define void @test12-4(i32* align 4 %p) {

  %p-cast = bitcast i32* %p to i64*

  %arrayidx0 = getelementptr i64, i64* %p-cast, i64 0