[llvm] r246502 - [BasicAA] Fix the handling of sext and zext in the analysis of GEPs.
Quentin Colombet via llvm-commits
llvm-commits at lists.llvm.org
Tue Oct 27 09:50:02 PDT 2015
Hi Tom,
I have to admit I haven’t followed the history of the commit closely, but I believe it was supposed to fix a bug that exists prior to r221876.
In other words, I think we would still need this, but I leave the final word to Hal.
Cheers,
-Quentin
> On Oct 27, 2015, at 8:50 AM, Tom Stellard <tom at stellard.net> wrote:
>
> On Thu, Sep 10, 2015 at 03:28:11PM -0700, Hans Wennborg wrote:
>> +Tom for 3.7.1
>>
>
> Do we still need this in the 3.7 branch? It looks like the commit that
> introduced the bug (r221876) was already reverted in the 3.7 branch.
>
> -Tom
>
>> On Mon, Aug 31, 2015 at 4:04 PM, Hans Wennborg <hans at chromium.org> wrote:
>>> The tag for 3.7.0 was committed last Friday, so it's too late for
>>> that, but it seems like a good candidate for 3.7.1.
>>>
>>> I'm putting it on my list and will let Tom know about it when he
>>> starts the 3.7.1 process.
>>>
>>> On Mon, Aug 31, 2015 at 3:40 PM, Quentin Colombet <qcolombet at apple.com> wrote:
>>>> Hi Hans,
>>>>
>>>> Following Hal's recommendation in D11847, I think we want to pull that into 3.7.
>>>>
>>>> Thanks,
>>>> -Quentin
>>>>> On Aug 31, 2015, at 3:32 PM, Quentin Colombet via llvm-commits <llvm-commits at lists.llvm.org> wrote:
>>>>>
>>>>> Author: qcolombet
>>>>> Date: Mon Aug 31 17:32:47 2015
>>>>> New Revision: 246502
>>>>>
>>>>> URL: http://llvm.org/viewvc/llvm-project?rev=246502&view=rev
>>>>> Log:
>>>>> [BasicAA] Fix the handling of sext and zext in the analysis of GEPs.
>>>>> Hopefully this will end the GEPs saga!
>>>>>
>>>>> This commit reverts r245394, i.e., it reapplies r221876 while incorporating the
>>>>> fixes from D11847.
>>>>> r221876 was not reapplied alone because it was not safe and D11847 was not
>>>>> applied alone because it needs r221876 to produce correct results.
>>>>>
>>>>> This should fix PR24596.
>>>>>
>>>>> Original commit message for r221876:
>>>>> Let's try this again...
>>>>>
>>>>> This reverts r219432, plus a bug fix.
>>>>>
>>>>> Description of the bug in r219432 (by Nick):
>>>>>
>>>>> The bug was using AllPositive to break out of the loop; if the loop break
>>>>> condition i != e is changed to i != e && AllPositive then the
>>>>> test_modulo_analysis_with_global test I've added will fail as the Modulo will
>>>>> be calculated incorrectly (as the last loop iteration is skipped, so Modulo
>>>>> isn't updated with its Scale).
>>>>>
>>>>> Nick also adds this comment:
>>>>>
>>>>> ComputeSignBit is safe to use in loops as it takes into account phi nodes, and
>>>>> the == EK_ZeroEx check is safe in loops as, no matter how the variable changes
>>>>> between iterations, zero-extensions will always guarantee a zero sign bit. The
>>>>> isValueEqualInPotentialCycles check is therefore definitely not needed as all
>>>>> the variable analysis holds no matter how the variables change between loop
>>>>> iterations.
>>>>>
>>>>> And this patch also adds another enhancement to GetLinearExpression - basically
>>>>> to convert ConstantInts to Offsets (see test_const_eval and
>>>>> test_const_eval_scaled for the situations this improves).
>>>>>
>>>>> Original commit message:
>>>>>
>>>>> This reverts r218944, which reverted r218714, plus a bug fix.
>>>>>
>>>>> Description of the bug in r218714 (by Nick):
>>>>>
>>>>> The original patch forgot to check if the Scale in VariableGEPIndex flipped the
>>>>> sign of the variable. The BasicAA pass iterates over the instructions in the
>>>>> order they appear in the function, and so BasicAliasAnalysis::aliasGEP is
>>>>> called with the variable it first comes across as parameter GEP1. Adding a
>>>>> %reorder label puts the definition of %a after %b so aliasGEP is called with %b
>>>>> as the first parameter and %a as the second. aliasGEP later calculates that %a
>>>>> == %b + 1 - %idxprom where %idxprom >= 0 (if %a was passed as the first
>>>>> parameter it would calculate %b == %a - 1 + %idxprom where %idxprom >= 0) -
>>>>> ignoring that %idxprom is scaled by -1 here lead the patch to incorrectly
>>>>> conclude that %a > %b.
>>>>>
>>>>> Revised patch by Nick White, thanks! Thanks to Lang to isolating the bug.
>>>>> Slightly modified by me to add an early exit from the loop and avoid
>>>>> unnecessary, but expensive, function calls.
>>>>>
>>>>> Original commit message:
>>>>>
>>>>> Two related things:
>>>>>
>>>>> 1. Fixes a bug when calculating the offset in GetLinearExpression. The code
>>>>> previously used zext to extend the offset, so negative offsets were converted
>>>>> to large positive ones.
>>>>>
>>>>> 2. Enhance aliasGEP to deduce that, if the difference between two GEP
>>>>> allocations is positive and all the variables that govern the offset are also
>>>>> positive (i.e. the offset is strictly after the higher base pointer), then
>>>>> locations that fit in the gap between the two base pointers are NoAlias.
>>>>>
>>>>> Patch by Nick White!
>>>>>
>>>>> Message from D11847:
>>>>> Un-revert of r241981 and fix for PR23626. The 'Or' case of GetLinearExpression
>>>>> delegates to 'Add' if possible, and if not it returns an Opaque value.
>>>>> Unfortunately the Scale and Offsets weren't being set (and so defaulted to 0) -
>>>>> and a scale of zero effectively removes the variable from the GEP instruction.
>>>>> This meant that BasicAA would return MustAliases when it should have been
>>>>> returning PartialAliases (and PR23626 was an example of the GVN pass using an
>>>>> incorrect MustAlias to merge loads from what should have been different
>>>>> pointers).
>>>>>
>>>>> Differential Revision: http://reviews.llvm.org/D11847
>>>>> Patch by Nick White <n.j.white at gmail.com>!
>>>>>
>>>>>
>>>>> Added:
>>>>> llvm/trunk/test/Analysis/BasicAA/bug.23540.ll
>>>>> llvm/trunk/test/Analysis/BasicAA/bug.23626.ll
>>>>> llvm/trunk/test/Analysis/BasicAA/q.bad.ll
>>>>> llvm/trunk/test/Analysis/BasicAA/zext.ll
>>>>> - copied, changed from r245393, llvm/trunk/test/Analysis/BasicAA/zext.ll
>>>>> Modified:
>>>>> llvm/trunk/include/llvm/Analysis/BasicAliasAnalysis.h
>>>>> llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp
>>>>> llvm/trunk/test/Analysis/BasicAA/phi-aa.ll
>>>>>
>>>>> Modified: llvm/trunk/include/llvm/Analysis/BasicAliasAnalysis.h
>>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/BasicAliasAnalysis.h?rev=246502&r1=246501&r2=246502&view=diff
>>>>> ==============================================================================
>>>>> --- llvm/trunk/include/llvm/Analysis/BasicAliasAnalysis.h (original)
>>>>> +++ llvm/trunk/include/llvm/Analysis/BasicAliasAnalysis.h Mon Aug 31 17:32:47 2015
>>>>> @@ -109,16 +109,25 @@ struct BasicAliasAnalysis : public Immut
>>>>> }
>>>>>
>>>>> private:
>>>>> - enum ExtensionKind { EK_NotExtended, EK_SignExt, EK_ZeroExt };
>>>>> -
>>>>> + // A linear transformation of a Value; this class represents ZExt(SExt(V,
>>>>> + // SExtBits), ZExtBits) * Scale + Offset.
>>>>> struct VariableGEPIndex {
>>>>> +
>>>>> + // An opaque Value - we can't decompose this further.
>>>>> const Value *V;
>>>>> - ExtensionKind Extension;
>>>>> +
>>>>> + // We need to track what extensions we've done as we consider the same Value
>>>>> + // with different extensions as different variables in a GEP's linear
>>>>> + // expression;
>>>>> + // e.g.: if V == -1, then sext(x) != zext(x).
>>>>> + unsigned ZExtBits;
>>>>> + unsigned SExtBits;
>>>>> +
>>>>> int64_t Scale;
>>>>>
>>>>> bool operator==(const VariableGEPIndex &Other) const {
>>>>> - return V == Other.V && Extension == Other.Extension &&
>>>>> - Scale == Other.Scale;
>>>>> + return V == Other.V && ZExtBits == Other.ZExtBits &&
>>>>> + SExtBits == Other.SExtBits && Scale == Other.Scale;
>>>>> }
>>>>>
>>>>> bool operator!=(const VariableGEPIndex &Other) const {
>>>>> @@ -150,16 +159,30 @@ private:
>>>>> /// Tracks instructions visited by pointsToConstantMemory.
>>>>> SmallPtrSet<const Value *, 16> Visited;
>>>>>
>>>>> - static Value *GetLinearExpression(Value *V, APInt &Scale, APInt &Offset,
>>>>> - ExtensionKind &Extension,
>>>>> - const DataLayout &DL, unsigned Depth,
>>>>> - AssumptionCache *AC, DominatorTree *DT);
>>>>> + static const Value *
>>>>> + GetLinearExpression(const Value *V, APInt &Scale, APInt &Offset,
>>>>> + unsigned &ZExtBits, unsigned &SExtBits,
>>>>> + const DataLayout &DL, unsigned Depth, AssumptionCache *AC,
>>>>> + DominatorTree *DT, bool &NSW, bool &NUW);
>>>>>
>>>>> static const Value *
>>>>> DecomposeGEPExpression(const Value *V, int64_t &BaseOffs,
>>>>> SmallVectorImpl<VariableGEPIndex> &VarIndices,
>>>>> bool &MaxLookupReached, const DataLayout &DL,
>>>>> AssumptionCache *AC, DominatorTree *DT);
>>>>> + /// \brief A Heuristic for aliasGEP that searches for a constant offset
>>>>> + /// between the variables.
>>>>> + ///
>>>>> + /// GetLinearExpression has some limitations, as generally zext(%x + 1)
>>>>> + /// != zext(%x) + zext(1) if the arithmetic overflows. GetLinearExpression
>>>>> + /// will therefore conservatively refuse to decompose these expressions.
>>>>> + /// However, we know that, for all %x, zext(%x) != zext(%x + 1), even if
>>>>> + /// the addition overflows.
>>>>> + bool
>>>>> + constantOffsetHeuristic(const SmallVectorImpl<VariableGEPIndex> &VarIndices,
>>>>> + uint64_t V1Size, uint64_t V2Size, int64_t BaseOffset,
>>>>> + const DataLayout *DL, AssumptionCache *AC,
>>>>> + DominatorTree *DT);
>>>>>
>>>>> bool isValueEqualInPotentialCycles(const Value *V1, const Value *V2);
>>>>>
>>>>>
>>>>> Modified: llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp
>>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp?rev=246502&r1=246501&r2=246502&view=diff
>>>>> ==============================================================================
>>>>> --- llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp (original)
>>>>> +++ llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp Mon Aug 31 17:32:47 2015
>>>>> @@ -177,10 +177,10 @@ static bool isObjectSize(const Value *V,
>>>>> ///
>>>>> /// Note that this looks through extends, so the high bits may not be
>>>>> /// represented in the result.
>>>>> -/*static*/ Value *BasicAliasAnalysis::GetLinearExpression(
>>>>> - Value *V, APInt &Scale, APInt &Offset, ExtensionKind &Extension,
>>>>> - const DataLayout &DL, unsigned Depth, AssumptionCache *AC,
>>>>> - DominatorTree *DT) {
>>>>> +/*static*/ const Value *BasicAliasAnalysis::GetLinearExpression(
>>>>> + const Value *V, APInt &Scale, APInt &Offset, unsigned &ZExtBits,
>>>>> + unsigned &SExtBits, const DataLayout &DL, unsigned Depth,
>>>>> + AssumptionCache *AC, DominatorTree *DT, bool &NSW, bool &NUW) {
>>>>> assert(V->getType()->isIntegerTy() && "Not an integer value");
>>>>>
>>>>> // Limit our recursion depth.
>>>>> @@ -190,55 +190,125 @@ static bool isObjectSize(const Value *V,
>>>>> return V;
>>>>> }
>>>>>
>>>>> - if (BinaryOperator *BOp = dyn_cast<BinaryOperator>(V)) {
>>>>> + if (const ConstantInt *Const = dyn_cast<ConstantInt>(V)) {
>>>>> + // if it's a constant, just convert it to an offset and remove the variable.
>>>>> + // If we've been called recursively the Offset bit width will be greater
>>>>> + // than the constant's (the Offset's always as wide as the outermost call),
>>>>> + // so we'll zext here and process any extension in the isa<SExtInst> &
>>>>> + // isa<ZExtInst> cases below.
>>>>> + Offset += Const->getValue().zextOrSelf(Offset.getBitWidth());
>>>>> + assert(Scale == 0 && "Constant values don't have a scale");
>>>>> + return V;
>>>>> + }
>>>>> +
>>>>> + if (const BinaryOperator *BOp = dyn_cast<BinaryOperator>(V)) {
>>>>> if (ConstantInt *RHSC = dyn_cast<ConstantInt>(BOp->getOperand(1))) {
>>>>> +
>>>>> + // If we've been called recursively then Offset and Scale will be wider
>>>>> + // that the BOp operands. We'll always zext it here as we'll process sign
>>>>> + // extensions below (see the isa<SExtInst> / isa<ZExtInst> cases).
>>>>> + APInt RHS = RHSC->getValue().zextOrSelf(Offset.getBitWidth());
>>>>> +
>>>>> switch (BOp->getOpcode()) {
>>>>> default:
>>>>> - break;
>>>>> + // We don't understand this instruction, so we can't decompose it any
>>>>> + // further.
>>>>> + Scale = 1;
>>>>> + Offset = 0;
>>>>> + return V;
>>>>> case Instruction::Or:
>>>>> // X|C == X+C if all the bits in C are unset in X. Otherwise we can't
>>>>> // analyze it.
>>>>> if (!MaskedValueIsZero(BOp->getOperand(0), RHSC->getValue(), DL, 0, AC,
>>>>> - BOp, DT))
>>>>> - break;
>>>>> + BOp, DT)) {
>>>>> + Scale = 1;
>>>>> + Offset = 0;
>>>>> + return V;
>>>>> + }
>>>>> // FALL THROUGH.
>>>>> case Instruction::Add:
>>>>> - V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, Extension,
>>>>> - DL, Depth + 1, AC, DT);
>>>>> - Offset += RHSC->getValue();
>>>>> - return V;
>>>>> + V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, ZExtBits,
>>>>> + SExtBits, DL, Depth + 1, AC, DT, NSW, NUW);
>>>>> + Offset += RHS;
>>>>> + break;
>>>>> + case Instruction::Sub:
>>>>> + V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, ZExtBits,
>>>>> + SExtBits, DL, Depth + 1, AC, DT, NSW, NUW);
>>>>> + Offset -= RHS;
>>>>> + break;
>>>>> case Instruction::Mul:
>>>>> - V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, Extension,
>>>>> - DL, Depth + 1, AC, DT);
>>>>> - Offset *= RHSC->getValue();
>>>>> - Scale *= RHSC->getValue();
>>>>> - return V;
>>>>> + V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, ZExtBits,
>>>>> + SExtBits, DL, Depth + 1, AC, DT, NSW, NUW);
>>>>> + Offset *= RHS;
>>>>> + Scale *= RHS;
>>>>> + break;
>>>>> case Instruction::Shl:
>>>>> - V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, Extension,
>>>>> - DL, Depth + 1, AC, DT);
>>>>> - Offset <<= RHSC->getValue().getLimitedValue();
>>>>> - Scale <<= RHSC->getValue().getLimitedValue();
>>>>> + V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, ZExtBits,
>>>>> + SExtBits, DL, Depth + 1, AC, DT, NSW, NUW);
>>>>> + Offset <<= RHS.getLimitedValue();
>>>>> + Scale <<= RHS.getLimitedValue();
>>>>> + // the semantics of nsw and nuw for left shifts don't match those of
>>>>> + // multiplications, so we won't propagate them.
>>>>> + NSW = NUW = false;
>>>>> return V;
>>>>> }
>>>>> +
>>>>> + if (isa<OverflowingBinaryOperator>(BOp)) {
>>>>> + NUW &= BOp->hasNoUnsignedWrap();
>>>>> + NSW &= BOp->hasNoSignedWrap();
>>>>> + }
>>>>> + return V;
>>>>> }
>>>>> }
>>>>>
>>>>> // Since GEP indices are sign extended anyway, we don't care about the high
>>>>> // bits of a sign or zero extended value - just scales and offsets. The
>>>>> // extensions have to be consistent though.
>>>>> - if ((isa<SExtInst>(V) && Extension != EK_ZeroExt) ||
>>>>> - (isa<ZExtInst>(V) && Extension != EK_SignExt)) {
>>>>> + if (isa<SExtInst>(V) || isa<ZExtInst>(V)) {
>>>>> Value *CastOp = cast<CastInst>(V)->getOperand(0);
>>>>> - unsigned OldWidth = Scale.getBitWidth();
>>>>> + unsigned NewWidth = V->getType()->getPrimitiveSizeInBits();
>>>>> unsigned SmallWidth = CastOp->getType()->getPrimitiveSizeInBits();
>>>>> - Scale = Scale.trunc(SmallWidth);
>>>>> - Offset = Offset.trunc(SmallWidth);
>>>>> - Extension = isa<SExtInst>(V) ? EK_SignExt : EK_ZeroExt;
>>>>> -
>>>>> - Value *Result = GetLinearExpression(CastOp, Scale, Offset, Extension, DL,
>>>>> - Depth + 1, AC, DT);
>>>>> - Scale = Scale.zext(OldWidth);
>>>>> - Offset = Offset.zext(OldWidth);
>>>>> + unsigned OldZExtBits = ZExtBits, OldSExtBits = SExtBits;
>>>>> + const Value *Result =
>>>>> + GetLinearExpression(CastOp, Scale, Offset, ZExtBits, SExtBits, DL,
>>>>> + Depth + 1, AC, DT, NSW, NUW);
>>>>> +
>>>>> + // zext(zext(%x)) == zext(%x), and similiarly for sext; we'll handle this
>>>>> + // by just incrementing the number of bits we've extended by.
>>>>> + unsigned ExtendedBy = NewWidth - SmallWidth;
>>>>> +
>>>>> + if (isa<SExtInst>(V) && ZExtBits == 0) {
>>>>> + // sext(sext(%x, a), b) == sext(%x, a + b)
>>>>> +
>>>>> + if (NSW) {
>>>>> + // We haven't sign-wrapped, so it's valid to decompose sext(%x + c)
>>>>> + // into sext(%x) + sext(c). We'll sext the Offset ourselves:
>>>>> + unsigned OldWidth = Offset.getBitWidth();
>>>>> + Offset = Offset.trunc(SmallWidth).sext(NewWidth).zextOrSelf(OldWidth);
>>>>> + } else {
>>>>> + // We may have signed-wrapped, so don't decompose sext(%x + c) into
>>>>> + // sext(%x) + sext(c)
>>>>> + Scale = 1;
>>>>> + Offset = 0;
>>>>> + Result = CastOp;
>>>>> + ZExtBits = OldZExtBits;
>>>>> + SExtBits = OldSExtBits;
>>>>> + }
>>>>> + SExtBits += ExtendedBy;
>>>>> + } else {
>>>>> + // sext(zext(%x, a), b) = zext(zext(%x, a), b) = zext(%x, a + b)
>>>>> +
>>>>> + if (!NUW) {
>>>>> + // We may have unsigned-wrapped, so don't decompose zext(%x + c) into
>>>>> + // zext(%x) + zext(c)
>>>>> + Scale = 1;
>>>>> + Offset = 0;
>>>>> + Result = CastOp;
>>>>> + ZExtBits = OldZExtBits;
>>>>> + SExtBits = OldSExtBits;
>>>>> + }
>>>>> + ZExtBits += ExtendedBy;
>>>>> + }
>>>>>
>>>>> return Result;
>>>>> }
>>>>> @@ -318,7 +388,7 @@ static bool isObjectSize(const Value *V,
>>>>> gep_type_iterator GTI = gep_type_begin(GEPOp);
>>>>> for (User::const_op_iterator I = GEPOp->op_begin() + 1, E = GEPOp->op_end();
>>>>> I != E; ++I) {
>>>>> - Value *Index = *I;
>>>>> + const Value *Index = *I;
>>>>> // Compute the (potentially symbolic) offset in bytes for this index.
>>>>> if (StructType *STy = dyn_cast<StructType>(*GTI++)) {
>>>>> // For a struct, add the member offset.
>>>>> @@ -331,7 +401,7 @@ static bool isObjectSize(const Value *V,
>>>>> }
>>>>>
>>>>> // For an array/pointer, add the element offset, explicitly scaled.
>>>>> - if (ConstantInt *CIdx = dyn_cast<ConstantInt>(Index)) {
>>>>> + if (const ConstantInt *CIdx = dyn_cast<ConstantInt>(Index)) {
>>>>> if (CIdx->isZero())
>>>>> continue;
>>>>> BaseOffs += DL.getTypeAllocSize(*GTI) * CIdx->getSExtValue();
>>>>> @@ -339,18 +409,20 @@ static bool isObjectSize(const Value *V,
>>>>> }
>>>>>
>>>>> uint64_t Scale = DL.getTypeAllocSize(*GTI);
>>>>> - ExtensionKind Extension = EK_NotExtended;
>>>>> + unsigned ZExtBits = 0, SExtBits = 0;
>>>>>
>>>>> // If the integer type is smaller than the pointer size, it is implicitly
>>>>> // sign extended to pointer size.
>>>>> unsigned Width = Index->getType()->getIntegerBitWidth();
>>>>> - if (DL.getPointerSizeInBits(AS) > Width)
>>>>> - Extension = EK_SignExt;
>>>>> + unsigned PointerSize = DL.getPointerSizeInBits(AS);
>>>>> + if (PointerSize > Width)
>>>>> + SExtBits += PointerSize - Width;
>>>>>
>>>>> // Use GetLinearExpression to decompose the index into a C1*V+C2 form.
>>>>> APInt IndexScale(Width, 0), IndexOffset(Width, 0);
>>>>> - Index = GetLinearExpression(Index, IndexScale, IndexOffset, Extension, DL,
>>>>> - 0, AC, DT);
>>>>> + bool NSW = true, NUW = true;
>>>>> + Index = GetLinearExpression(Index, IndexScale, IndexOffset, ZExtBits,
>>>>> + SExtBits, DL, 0, AC, DT, NSW, NUW);
>>>>>
>>>>> // The GEP index scale ("Scale") scales C1*V+C2, yielding (C1*V+C2)*Scale.
>>>>> // This gives us an aggregate computation of (C1*Scale)*V + C2*Scale.
>>>>> @@ -362,7 +434,8 @@ static bool isObjectSize(const Value *V,
>>>>> // A[x][x] -> x*16 + x*4 -> x*20
>>>>> // This also ensures that 'x' only appears in the index list once.
>>>>> for (unsigned i = 0, e = VarIndices.size(); i != e; ++i) {
>>>>> - if (VarIndices[i].V == Index && VarIndices[i].Extension == Extension) {
>>>>> + if (VarIndices[i].V == Index && VarIndices[i].ZExtBits == ZExtBits &&
>>>>> + VarIndices[i].SExtBits == SExtBits) {
>>>>> Scale += VarIndices[i].Scale;
>>>>> VarIndices.erase(VarIndices.begin() + i);
>>>>> break;
>>>>> @@ -371,13 +444,13 @@ static bool isObjectSize(const Value *V,
>>>>>
>>>>> // Make sure that we have a scale that makes sense for this target's
>>>>> // pointer size.
>>>>> - if (unsigned ShiftBits = 64 - DL.getPointerSizeInBits(AS)) {
>>>>> + if (unsigned ShiftBits = 64 - PointerSize) {
>>>>> Scale <<= ShiftBits;
>>>>> Scale = (int64_t)Scale >> ShiftBits;
>>>>> }
>>>>>
>>>>> if (Scale) {
>>>>> - VariableGEPIndex Entry = {Index, Extension,
>>>>> + VariableGEPIndex Entry = {Index, ZExtBits, SExtBits,
>>>>> static_cast<int64_t>(Scale)};
>>>>> VarIndices.push_back(Entry);
>>>>> }
>>>>> @@ -948,12 +1021,42 @@ AliasResult BasicAliasAnalysis::aliasGEP
>>>>> }
>>>>> }
>>>>>
>>>>> - // Try to distinguish something like &A[i][1] against &A[42][0].
>>>>> - // Grab the least significant bit set in any of the scales.
>>>>> if (!GEP1VariableIndices.empty()) {
>>>>> uint64_t Modulo = 0;
>>>>> - for (unsigned i = 0, e = GEP1VariableIndices.size(); i != e; ++i)
>>>>> + bool AllPositive = true;
>>>>> + for (unsigned i = 0, e = GEP1VariableIndices.size(); i != e; ++i) {
>>>>> +
>>>>> + // Try to distinguish something like &A[i][1] against &A[42][0].
>>>>> + // Grab the least significant bit set in any of the scales. We
>>>>> + // don't need std::abs here (even if the scale's negative) as we'll
>>>>> + // be ^'ing Modulo with itself later.
>>>>> Modulo |= (uint64_t)GEP1VariableIndices[i].Scale;
>>>>> +
>>>>> + if (AllPositive) {
>>>>> + // If the Value could change between cycles, then any reasoning about
>>>>> + // the Value this cycle may not hold in the next cycle. We'll just
>>>>> + // give up if we can't determine conditions that hold for every cycle:
>>>>> + const Value *V = GEP1VariableIndices[i].V;
>>>>> +
>>>>> + bool SignKnownZero, SignKnownOne;
>>>>> + ComputeSignBit(const_cast<Value *>(V), SignKnownZero, SignKnownOne, *DL,
>>>>> + 0, AC1, nullptr, DT);
>>>>> +
>>>>> + // Zero-extension widens the variable, and so forces the sign
>>>>> + // bit to zero.
>>>>> + bool IsZExt = GEP1VariableIndices[i].ZExtBits > 0 || isa<ZExtInst>(V);
>>>>> + SignKnownZero |= IsZExt;
>>>>> + SignKnownOne &= !IsZExt;
>>>>> +
>>>>> + // If the variable begins with a zero then we know it's
>>>>> + // positive, regardless of whether the value is signed or
>>>>> + // unsigned.
>>>>> + int64_t Scale = GEP1VariableIndices[i].Scale;
>>>>> + AllPositive =
>>>>> + (SignKnownZero && Scale >= 0) || (SignKnownOne && Scale < 0);
>>>>> + }
>>>>> + }
>>>>> +
>>>>> Modulo = Modulo ^ (Modulo & (Modulo - 1));
>>>>>
>>>>> // We can compute the difference between the two addresses
>>>>> @@ -964,6 +1067,16 @@ AliasResult BasicAliasAnalysis::aliasGEP
>>>>> V2Size != MemoryLocation::UnknownSize && ModOffset >= V2Size &&
>>>>> V1Size <= Modulo - ModOffset)
>>>>> return NoAlias;
>>>>> +
>>>>> + // If we know all the variables are positive, then GEP1 >= GEP1BasePtr.
>>>>> + // If GEP1BasePtr > V2 (GEP1BaseOffset > 0) then we know the pointers
>>>>> + // don't alias if V2Size can fit in the gap between V2 and GEP1BasePtr.
>>>>> + if (AllPositive && GEP1BaseOffset > 0 && V2Size <= (uint64_t)GEP1BaseOffset)
>>>>> + return NoAlias;
>>>>> +
>>>>> + if (constantOffsetHeuristic(GEP1VariableIndices, V1Size, V2Size,
>>>>> + GEP1BaseOffset, DL, AC1, DT))
>>>>> + return NoAlias;
>>>>> }
>>>>>
>>>>> // Statically, we can see that the base objects are the same, but the
>>>>> @@ -1333,14 +1446,14 @@ void BasicAliasAnalysis::GetIndexDiffere
>>>>>
>>>>> for (unsigned i = 0, e = Src.size(); i != e; ++i) {
>>>>> const Value *V = Src[i].V;
>>>>> - ExtensionKind Extension = Src[i].Extension;
>>>>> + unsigned ZExtBits = Src[i].ZExtBits, SExtBits = Src[i].SExtBits;
>>>>> int64_t Scale = Src[i].Scale;
>>>>>
>>>>> // Find V in Dest. This is N^2, but pointer indices almost never have more
>>>>> // than a few variable indexes.
>>>>> for (unsigned j = 0, e = Dest.size(); j != e; ++j) {
>>>>> if (!isValueEqualInPotentialCycles(Dest[j].V, V) ||
>>>>> - Dest[j].Extension != Extension)
>>>>> + Dest[j].ZExtBits != ZExtBits || Dest[j].SExtBits != SExtBits)
>>>>> continue;
>>>>>
>>>>> // If we found it, subtract off Scale V's from the entry in Dest. If it
>>>>> @@ -1355,8 +1468,62 @@ void BasicAliasAnalysis::GetIndexDiffere
>>>>>
>>>>> // If we didn't consume this entry, add it to the end of the Dest list.
>>>>> if (Scale) {
>>>>> - VariableGEPIndex Entry = {V, Extension, -Scale};
>>>>> + VariableGEPIndex Entry = {V, ZExtBits, SExtBits, -Scale};
>>>>> Dest.push_back(Entry);
>>>>> }
>>>>> }
>>>>> }
>>>>> +
>>>>> +bool BasicAliasAnalysis::constantOffsetHeuristic(
>>>>> + const SmallVectorImpl<VariableGEPIndex> &VarIndices, uint64_t V1Size,
>>>>> + uint64_t V2Size, int64_t BaseOffset, const DataLayout *DL,
>>>>> + AssumptionCache *AC, DominatorTree *DT) {
>>>>> + if (VarIndices.size() != 2 || V1Size == MemoryLocation::UnknownSize ||
>>>>> + V2Size == MemoryLocation::UnknownSize || !DL)
>>>>> + return false;
>>>>> +
>>>>> + const VariableGEPIndex &Var0 = VarIndices[0], &Var1 = VarIndices[1];
>>>>> +
>>>>> + if (Var0.ZExtBits != Var1.ZExtBits || Var0.SExtBits != Var1.SExtBits ||
>>>>> + Var0.Scale != -Var1.Scale)
>>>>> + return false;
>>>>> +
>>>>> + unsigned Width = Var1.V->getType()->getIntegerBitWidth();
>>>>> +
>>>>> + // We'll strip off the Extensions of Var0 and Var1 and do another round
>>>>> + // of GetLinearExpression decomposition. In the example above, if Var0
>>>>> + // is zext(%x + 1) we should get V1 == %x and V1Offset == 1.
>>>>> +
>>>>> + APInt V0Scale(Width, 0), V0Offset(Width, 0), V1Scale(Width, 0),
>>>>> + V1Offset(Width, 0);
>>>>> + bool NSW = true, NUW = true;
>>>>> + unsigned V0ZExtBits = 0, V0SExtBits = 0, V1ZExtBits = 0, V1SExtBits = 0;
>>>>> + const Value *V0 = GetLinearExpression(Var0.V, V0Scale, V0Offset, V0ZExtBits,
>>>>> + V0SExtBits, *DL, 0, AC, DT, NSW, NUW);
>>>>> + NSW = true, NUW = true;
>>>>> + const Value *V1 = GetLinearExpression(Var1.V, V1Scale, V1Offset, V1ZExtBits,
>>>>> + V1SExtBits, *DL, 0, AC, DT, NSW, NUW);
>>>>> +
>>>>> + if (V0Scale != V1Scale || V0ZExtBits != V1ZExtBits ||
>>>>> + V0SExtBits != V1SExtBits || !isValueEqualInPotentialCycles(V0, V1))
>>>>> + return false;
>>>>> +
>>>>> + // We have a hit - Var0 and Var1 only differ by a constant offset!
>>>>> +
>>>>> + // If we've been sext'ed then zext'd the maximum difference between Var0 and
>>>>> + // Var1 is possible to calculate, but we're just interested in the absolute
>>>>> + // minumum difference between the two. The minimum distance may occur due to
>>>>> + // wrapping; consider "add i3 %i, 5": if %i == 7 then 7 + 5 mod 8 == 4, and so
>>>>> + // the minimum distance between %i and %i + 5 is 3.
>>>>> + APInt MinDiff = V0Offset - V1Offset,
>>>>> + Wrapped = APInt::getMaxValue(Width) - MinDiff + APInt(Width, 1);
>>>>> + MinDiff = APIntOps::umin(MinDiff, Wrapped);
>>>>> + uint64_t MinDiffBytes = MinDiff.getZExtValue() * std::abs(Var0.Scale);
>>>>> +
>>>>> + // We can't definitely say whether GEP1 is before or after V2 due to wrapping
>>>>> + // arithmetic (i.e. for some values of GEP1 and V2 GEP1 < V2, and for other
>>>>> + // values GEP1 > V2). We'll therefore only declare NoAlias if both V1Size and
>>>>> + // V2Size can fit in the MinDiffBytes gap.
>>>>> + return V1Size + std::abs(BaseOffset) <= MinDiffBytes &&
>>>>> + V2Size + std::abs(BaseOffset) <= MinDiffBytes;
>>>>> +}
>>>>>
>>>>> Added: llvm/trunk/test/Analysis/BasicAA/bug.23540.ll
>>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/BasicAA/bug.23540.ll?rev=246502&view=auto
>>>>> ==============================================================================
>>>>> --- llvm/trunk/test/Analysis/BasicAA/bug.23540.ll (added)
>>>>> +++ llvm/trunk/test/Analysis/BasicAA/bug.23540.ll Mon Aug 31 17:32:47 2015
>>>>> @@ -0,0 +1,17 @@
>>>>> +; RUN: opt < %s -basicaa -aa-eval -print-all-alias-modref-info -disable-output 2>&1 | FileCheck %s
>>>>> +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
>>>>> +target triple = "x86_64-unknown-linux-gnu"
>>>>> +
>>>>> + at c = external global i32
>>>>> +
>>>>> +; CHECK-LABEL: f
>>>>> +; CHECK: PartialAlias: i32* %arrayidx, i32* %arrayidx6
>>>>> +define void @f() {
>>>>> + %idxprom = zext i32 undef to i64
>>>>> + %add4 = add i32 0, 1
>>>>> + %idxprom5 = zext i32 %add4 to i64
>>>>> + %arrayidx6 = getelementptr inbounds i32, i32* @c, i64 %idxprom5
>>>>> + %arrayidx = getelementptr inbounds i32, i32* @c, i64 %idxprom
>>>>> + ret void
>>>>> +}
>>>>> +
>>>>>
>>>>> Added: llvm/trunk/test/Analysis/BasicAA/bug.23626.ll
>>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/BasicAA/bug.23626.ll?rev=246502&view=auto
>>>>> ==============================================================================
>>>>> --- llvm/trunk/test/Analysis/BasicAA/bug.23626.ll (added)
>>>>> +++ llvm/trunk/test/Analysis/BasicAA/bug.23626.ll Mon Aug 31 17:32:47 2015
>>>>> @@ -0,0 +1,31 @@
>>>>> +; RUN: opt < %s -basicaa -aa-eval -print-all-alias-modref-info -disable-output 2>&1 | FileCheck %s
>>>>> +target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
>>>>> +target triple = "x86_64-apple-darwin13.4.0"
>>>>> +
>>>>> +; CHECK-LABEL: compute1
>>>>> +; CHECK: PartialAlias: i32* %arrayidx8, i32* %out
>>>>> +; CHECK: PartialAlias: i32* %arrayidx11, i32* %out
>>>>> +; CHECK: PartialAlias: i32* %arrayidx11, i32* %arrayidx8
>>>>> +; CHECK: PartialAlias: i32* %arrayidx14, i32* %out
>>>>> +; CHECK: PartialAlias: i32* %arrayidx14, i32* %arrayidx8
>>>>> +; CHECK: PartialAlias: i32* %arrayidx11, i32* %arrayidx14
>>>>> +define void @compute1(i32 %num.0.lcssa, i32* %out) {
>>>>> + %idxprom = zext i32 %num.0.lcssa to i64
>>>>> + %arrayidx8 = getelementptr inbounds i32, i32* %out, i64 %idxprom
>>>>> + %add9 = or i32 %num.0.lcssa, 1
>>>>> + %idxprom10 = zext i32 %add9 to i64
>>>>> + %arrayidx11 = getelementptr inbounds i32, i32* %out, i64 %idxprom10
>>>>> + %add12 = or i32 %num.0.lcssa, 2
>>>>> + %idxprom13 = zext i32 %add12 to i64
>>>>> + %arrayidx14 = getelementptr inbounds i32, i32* %out, i64 %idxprom13
>>>>> + ret void
>>>>> +}
>>>>> +
>>>>> +; CHECK-LABEL: compute2
>>>>> +; CHECK: PartialAlias: i32* %arrayidx11, i32* %out.addr
>>>>> +define void @compute2(i32 %num, i32* %out.addr) {
>>>>> + %add9 = add i32 %num, 1
>>>>> + %idxprom10 = zext i32 %add9 to i64
>>>>> + %arrayidx11 = getelementptr inbounds i32, i32* %out.addr, i64 %idxprom10
>>>>> + ret void
>>>>> +}
>>>>>
>>>>> Modified: llvm/trunk/test/Analysis/BasicAA/phi-aa.ll
>>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/BasicAA/phi-aa.ll?rev=246502&r1=246501&r2=246502&view=diff
>>>>> ==============================================================================
>>>>> --- llvm/trunk/test/Analysis/BasicAA/phi-aa.ll (original)
>>>>> +++ llvm/trunk/test/Analysis/BasicAA/phi-aa.ll Mon Aug 31 17:32:47 2015
>>>>> @@ -39,6 +39,7 @@ return:
>>>>>
>>>>> ; CHECK-LABEL: pr18068
>>>>> ; CHECK: MayAlias: i32* %0, i32* %arrayidx5
>>>>> +; CHECK: NoAlias: i32* %arrayidx13, i32* %arrayidx5
>>>>>
>>>>> define i32 @pr18068(i32* %jj7, i32* %j) {
>>>>> entry:
>>>>>
>>>>> Added: llvm/trunk/test/Analysis/BasicAA/q.bad.ll
>>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/BasicAA/q.bad.ll?rev=246502&view=auto
>>>>> ==============================================================================
>>>>> --- llvm/trunk/test/Analysis/BasicAA/q.bad.ll (added)
>>>>> +++ llvm/trunk/test/Analysis/BasicAA/q.bad.ll Mon Aug 31 17:32:47 2015
>>>>> @@ -0,0 +1,180 @@
>>>>> +; RUN: opt < %s -basicaa -aa-eval -print-all-alias-modref-info -disable-output 2>&1 | FileCheck %s
>>>>> +target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64"
>>>>> +target triple = "thumbv7--linux-gnueabi"
>>>>> +
>>>>> +; CHECK-LABEL: test_zext_sext_amounts255
>>>>> +; CHECK: NoAlias: i8* %a, i8* %b
>>>>> +define void @test_zext_sext_amounts255(i8* %mem) {
>>>>> + %sext.1 = sext i8 255 to i16
>>>>> + %sext.zext.1 = zext i16 %sext.1 to i64
>>>>> + %sext.2 = sext i8 255 to i32
>>>>> + %sext.zext.2 = zext i32 %sext.2 to i64
>>>>> + %a = getelementptr inbounds i8, i8* %mem, i64 %sext.zext.1
>>>>> + %b = getelementptr inbounds i8, i8* %mem, i64 %sext.zext.2
>>>>> + ret void
>>>>> +}
>>>>> +
>>>>> +; CHECK-LABEL: test_zext_sext_amounts
>>>>> +; CHECK: PartialAlias: i8* %a, i8* %b
>>>>> +; %a and %b only PartialAlias as, although they're both zext(sext(%num)) they'll extend the sign by a different
>>>>> +; number of bits before zext-ing the remainder.
>>>>> +define void @test_zext_sext_amounts(i8* %mem, i8 %num) {
>>>>> + %sext.1 = sext i8 %num to i16
>>>>> + %sext.zext.1 = zext i16 %sext.1 to i64
>>>>> + %sext.2 = sext i8 %num to i32
>>>>> + %sext.zext.2 = zext i32 %sext.2 to i64
>>>>> + %a = getelementptr inbounds i8, i8* %mem, i64 %sext.zext.1
>>>>> + %b = getelementptr inbounds i8, i8* %mem, i64 %sext.zext.2
>>>>> + ret void
>>>>> +}
>>>>> +
>>>>> +; CHECK-LABEL: based_on_pr18068
>>>>> +; CHECK: NoAlias: i8* %a, i8* %b
>>>>> +; CHECK: NoAlias: i8* %a, i8* %c
>>>>> +define void @based_on_pr18068(i32 %loaded, i8* %mem) {
>>>>> + %loaded.64 = zext i32 %loaded to i64
>>>>> + %add1 = add i32 %loaded, -1 ; unsigned wraps unless %loaded == 0
>>>>> + %add1.64 = zext i32 %add1 to i64 ; is zext(%loaded) always != zext(%loaded - 1)? Yes -> NoAlias
>>>>> + %sub1 = sub i32 %loaded, 1 ; unsigned wraps iff %loaded == 0
>>>>> + %sub1.64 = zext i32 %sub1 to i64 ; is zext(%loaded) always != zext(%loaded - 1)? Yes -> NoAlias
>>>>> + %a = getelementptr inbounds i8, i8* %mem, i64 %loaded.64
>>>>> + %b = getelementptr inbounds i8, i8* %mem, i64 %add1.64
>>>>> + %c = getelementptr inbounds i8, i8* %mem, i64 %sub1.64
>>>>> + ret void
>>>>> +}
>>>>> +
>>>>> +; CHECK-LABEL: test_path_dependence
>>>>> +; CHECK: PartialAlias: i8* %a, i8* %b
>>>>> +; CHECK: MustAlias: i8* %a, i8* %c
>>>>> +; CHECK: PartialAlias: i8* %a, i8* %d
>>>>> +define void @test_path_dependence(i32 %p, i8* %mem) {
>>>>> + %p.minus1 = add i32 %p, -1 ; this will always unsigned-wrap, unless %p == 0
>>>>> + %p.minus1.64 = zext i32 %p.minus1 to i64
>>>>> + %p.64.again = add i64 %p.minus1.64, 1 ; either %p (if we wrapped) or 4294967296 (if we didn't)
>>>>> +
>>>>> + %p.nsw.nuw.minus1 = sub nsw nuw i32 %p, 1 ; as nuw we know %p >= 1, and as nsw %p <= 2147483647
>>>>> + %p.nsw.nuw.minus1.64 = zext i32 %p.nsw.nuw.minus1 to i64
>>>>> + %p.nsw.nuw.64.again = add nsw nuw i64 %p.nsw.nuw.minus1.64, 1 ; ...so always exactly %p
>>>>> +
>>>>> + %p.nsw.minus1 = sub nsw i32 %p, 1 ; only nsw, so can only guarantee %p != 0x10000000
>>>>> + %p.nsw.minus1.64 = zext i32 %p.nsw.minus1 to i64 ; when %p > 0x10000000 (ie <= 0 as a signed number) then the zext will make this a huge positive number
>>>>> + %p.nsw.64.again = add nsw i64 %p.nsw.minus1.64, 1 ; ...and so this is very much != %p
>>>>> +
>>>>> + %p.64 = zext i32 %p to i64
>>>>> + %a = getelementptr inbounds i8, i8* %mem, i64 %p.64
>>>>> + %b = getelementptr inbounds i8, i8* %mem, i64 %p.64.again
>>>>> + %c = getelementptr inbounds i8, i8* %mem, i64 %p.nsw.nuw.64.again
>>>>> + %d = getelementptr inbounds i8, i8* %mem, i64 %p.nsw.64.again
>>>>> + ret void
>>>>> +}
>>>>> +
>>>>> +; CHECK-LABEL: test_zext_sext_255
>>>>> +; CHECK: NoAlias: i8* %a, i8* %b
>>>>> +define void @test_zext_sext_255(i8* %mem) {
>>>>> + %zext.255 = zext i8 255 to i16 ; 0x00FF
>>>>> + %sext.255 = sext i8 255 to i16 ; 0xFFFF
>>>>> + %zext.sext.255 = zext i16 %sext.255 to i32 ; 0x0000FFFF
>>>>> + %sext.zext.255 = sext i16 %zext.255 to i32 ; 0x000000FF
>>>>> + %zext.zext.sext.255 = zext i32 %zext.sext.255 to i64
>>>>> + %zext.sext.zext.255 = zext i32 %sext.zext.255 to i64
>>>>> + %a = getelementptr inbounds i8, i8* %mem, i64 %zext.zext.sext.255
>>>>> + %b = getelementptr inbounds i8, i8* %mem, i64 %zext.sext.zext.255
>>>>> + ret void
>>>>> +}
>>>>> +
>>>>> +; CHECK-LABEL: test_zext_sext_num
>>>>> +; CHECK: PartialAlias: i8* %a, i8* %b
>>>>> +; %a and %b NoAlias if %num == 255 (see @test_zext_sext_255), but %a and %b NoAlias for other values of %num (e.g. 0)
>>>>> +define void @test_zext_sext_num(i8* %mem, i8 %num) {
>>>>> + %zext.num = zext i8 %num to i16
>>>>> + %sext.num = sext i8 %num to i16
>>>>> + %zext.sext.num = zext i16 %sext.num to i32
>>>>> + %sext.zext.num = sext i16 %zext.num to i32
>>>>> + %zext.zext.sext.num = zext i32 %zext.sext.num to i64
>>>>> + %zext.sext.zext.num = zext i32 %sext.zext.num to i64
>>>>> + %a = getelementptr inbounds i8, i8* %mem, i64 %zext.zext.sext.num
>>>>> + %b = getelementptr inbounds i8, i8* %mem, i64 %zext.sext.zext.num
>>>>> + ret void
>>>>> +}
>>>>> +
>>>>> +; CHECK-LABEL: uncompressStream
>>>>> +; CHECK: MustAlias: i8* %a, i8* %b
>>>>> +; CHECK: NoAlias: i8* %a, i8* %c
>>>>> +define void @uncompressStream(i8* %mem) {
>>>>> + %zext.255 = zext i8 255 to i32
>>>>> + %sext.255 = sext i8 255 to i32
>>>>> + %a = getelementptr inbounds i8, i8* %mem, i32 255
>>>>> + %b = getelementptr inbounds i8, i8* %mem, i32 %zext.255
>>>>> + %c = getelementptr inbounds i8, i8* %mem, i32 %sext.255
>>>>> + ret void
>>>>> +}
>>>>> +
>>>>> +; CHECK-LABEL: constantOffsetHeuristic_i3_i32
>>>>> +; CHECK: NoAlias: i32* %a, i32* %b
>>>>> +; CHECK: NoAlias: i32* %a, i32* %c
>>>>> +; CHECK: NoAlias: i32* %b, i32* %c
>>>>> +define void @constantOffsetHeuristic_i3_i32(i32* %mem, i3 %val) {
>>>>> + %zext.plus.7 = add nsw i3 %val, 7
>>>>> + %zext.plus.4 = add nsw i3 %val, 4
>>>>> + %zext.val = zext i3 %val to i32
>>>>> + %zext.4 = zext i3 %zext.plus.4 to i32
>>>>> + %zext.7 = zext i3 %zext.plus.7 to i32
>>>>> + %a = getelementptr inbounds i32, i32* %mem, i32 %zext.4
>>>>> + %b = getelementptr inbounds i32, i32* %mem, i32 %zext.7
>>>>> + %c = getelementptr inbounds i32, i32* %mem, i32 %zext.val
>>>>> + ret void
>>>>> +}
>>>>> +
>>>>> +; CHECK-LABEL: constantOffsetHeuristic_i8_i32
>>>>> +; CHECK: NoAlias: i32* %a, i32* %b
>>>>> +; CHECK: NoAlias: i32* %a, i32* %c
>>>>> +; CHECK: NoAlias: i32* %b, i32* %c
>>>>> +define void @constantOffsetHeuristic_i8_i32(i32* %mem, i8 %val) {
>>>>> + %zext.plus.7 = add nsw i8 %val, 7
>>>>> + %zext.plus.4 = add nsw i8 %val, 4
>>>>> + %zext.val = zext i8 %val to i32
>>>>> + %zext.4 = zext i8 %zext.plus.4 to i32
>>>>> + %zext.7 = zext i8 %zext.plus.7 to i32
>>>>> + %a = getelementptr inbounds i32, i32* %mem, i32 %zext.4
>>>>> + %b = getelementptr inbounds i32, i32* %mem, i32 %zext.7
>>>>> + %c = getelementptr inbounds i32, i32* %mem, i32 %zext.val
>>>>> + ret void
>>>>> +}
>>>>> +
>>>>> +; CHECK-LABEL: constantOffsetHeuristic_i3_i8
>>>>> +; CHECK: PartialAlias: i32* %a, i32* %b
>>>>> +; CHECK: NoAlias: i32* %a, i32* %c
>>>>> +; CHECK: PartialAlias: i32* %b, i32* %c
>>>>> +define void @constantOffsetHeuristic_i3_i8(i8* %mem, i3 %val) {
>>>>> + %zext.plus.7 = add nsw i3 %val, 7
>>>>> + %zext.plus.4 = add nsw i3 %val, 4
>>>>> + %zext.val = zext i3 %val to i32
>>>>> + %zext.4 = zext i3 %zext.plus.4 to i32
>>>>> + %zext.7 = zext i3 %zext.plus.7 to i32
>>>>> + %a.8 = getelementptr inbounds i8, i8* %mem, i32 %zext.4
>>>>> + %b.8 = getelementptr inbounds i8, i8* %mem, i32 %zext.7
>>>>> + %c.8 = getelementptr inbounds i8, i8* %mem, i32 %zext.val
>>>>> + %a = bitcast i8* %a.8 to i32*
>>>>> + %b = bitcast i8* %b.8 to i32*
>>>>> + %c = bitcast i8* %c.8 to i32*
>>>>> + ret void
>>>>> +}
>>>>> +
>>>>> +; CHECK-LABEL: constantOffsetHeuristic_i8_i8
>>>>> +; CHECK: PartialAlias: i32* %a, i32* %b
>>>>> +; CHECK: NoAlias: i32* %a, i32* %c
>>>>> +; CHECK: NoAlias: i32* %b, i32* %c
>>>>> +define void @constantOffsetHeuristic_i8_i8(i8* %mem, i8 %val) {
>>>>> + %zext.plus.7 = add nsw i8 %val, 7
>>>>> + %zext.plus.4 = add nsw i8 %val, 4
>>>>> + %zext.val = zext i8 %val to i32
>>>>> + %zext.4 = zext i8 %zext.plus.4 to i32
>>>>> + %zext.7 = zext i8 %zext.plus.7 to i32
>>>>> + %a.8 = getelementptr inbounds i8, i8* %mem, i32 %zext.4
>>>>> + %b.8 = getelementptr inbounds i8, i8* %mem, i32 %zext.7
>>>>> + %c.8 = getelementptr inbounds i8, i8* %mem, i32 %zext.val
>>>>> + %a = bitcast i8* %a.8 to i32*
>>>>> + %b = bitcast i8* %b.8 to i32*
>>>>> + %c = bitcast i8* %c.8 to i32*
>>>>> + ret void
>>>>> +}
>>>>>
>>>>> Copied: llvm/trunk/test/Analysis/BasicAA/zext.ll (from r245393, llvm/trunk/test/Analysis/BasicAA/zext.ll)
>>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/BasicAA/zext.ll?p2=llvm/trunk/test/Analysis/BasicAA/zext.ll&p1=llvm/trunk/test/Analysis/BasicAA/zext.ll&r1=245393&r2=246502&rev=246502&view=diff
>>>>> ==============================================================================
>>>>> --- llvm/trunk/test/Analysis/BasicAA/zext.ll (original)
>>>>> +++ llvm/trunk/test/Analysis/BasicAA/zext.ll Mon Aug 31 17:32:47 2015
>>>>> @@ -205,5 +205,27 @@ define void @test_const_eval_scaled(i8*
>>>>> ret void
>>>>> }
>>>>>
>>>>> +; CHECK-LABEL: Function: foo
>>>>> +; CHECK: MustAlias: float* %arrayidx, float* %arrayidx4.84
>>>>> +define float @foo(i32 *%A, float %rend, float** %wayar) {
>>>>> +entry:
>>>>> + %x0 = load i32, i32* %A, align 4
>>>>> + %conv = sext i32 %x0 to i64
>>>>> + %mul = shl nsw i64 %conv, 3
>>>>> + %call = tail call i8* @malloc(i64 %mul)
>>>>> + %x1 = bitcast i8* %call to float*
>>>>> +
>>>>> + %sub = add nsw i32 %x0, -1
>>>>> + %idxprom = sext i32 %sub to i64
>>>>> + %arrayidx = getelementptr inbounds float, float* %x1, i64 %idxprom
>>>>> + store float %rend, float* %arrayidx, align 8
>>>>> +
>>>>> + %indvars.iv76.83 = add nsw i64 %conv, -1
>>>>> + %arrayidx4.84 = getelementptr inbounds float, float* %x1, i64 %indvars.iv76.83
>>>>> + %x4 = load float, float* %arrayidx4.84, align 8
>>>>> +
>>>>> + ret float %x4
>>>>> +}
>>>>> +
>>>>> ; Function Attrs: nounwind
>>>>> declare noalias i8* @malloc(i64)
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> llvm-commits mailing list
>>>>> llvm-commits at lists.llvm.org
>>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>>>>
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