[llvm] r242025 - Revert r241981 "Revert "Revert r236894 "[BasicAA] Fix zext & sext handling"""
Manuel Klimek
klimek at google.com
Mon Jul 13 06:50:56 PDT 2015
Author: klimek
Date: Mon Jul 13 08:50:55 2015
New Revision: 242025
URL: http://llvm.org/viewvc/llvm-project?rev=242025&view=rev
Log:
Revert r241981 "Revert "Revert r236894 "[BasicAA] Fix zext & sext handling"""
The repros from PR23626 still fail.
Removed:
llvm/trunk/test/Analysis/BasicAA/bug.23540.ll
llvm/trunk/test/Analysis/BasicAA/q.bad.ll
Modified:
llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp
Modified: llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp?rev=242025&r1=242024&r2=242025&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp (original)
+++ llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp Mon Jul 13 08:50:55 2015
@@ -162,26 +162,20 @@ static bool isObjectSize(const Value *V,
//===----------------------------------------------------------------------===//
namespace {
+ 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;
-
- // 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;
-
+ ExtensionKind Extension;
int64_t Scale;
bool operator==(const VariableGEPIndex &Other) const {
- return V == Other.V && ZExtBits == Other.ZExtBits &&
- SExtBits == Other.SExtBits && Scale == Other.Scale;
+ return V == Other.V && Extension == Other.Extension &&
+ Scale == Other.Scale;
}
bool operator!=(const VariableGEPIndex &Other) const {
@@ -199,12 +193,10 @@ namespace {
///
/// Note that this looks through extends, so the high bits may not be
/// represented in the result.
-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 Value *GetLinearExpression(Value *V, APInt &Scale, APInt &Offset,
+ ExtensionKind &Extension,
+ const DataLayout &DL, unsigned Depth,
+ AssumptionCache *AC, DominatorTree *DT) {
assert(V->getType()->isIntegerTy() && "Not an integer value");
// Limit our recursion depth.
@@ -214,32 +206,18 @@ static const Value *GetLinearExpression(
return 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());
+ if (ConstantInt *Const = dyn_cast<ConstantInt>(V)) {
+ // if it's a constant, just convert it to an offset
+ // and remove the variable.
+ Offset += Const->getValue();
assert(Scale == 0 && "Constant values don't have a scale");
return V;
}
- if (const BinaryOperator *BOp = dyn_cast<BinaryOperator>(V)) {
+ if (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:
- // We don't understand this instruction, so we can't decompose it any
- // further.
- Scale = 1;
- Offset = 0;
- return V;
+ default: break;
case Instruction::Or:
// X|C == X+C if all the bits in C are unset in X. Otherwise we can't
// analyze it.
@@ -248,88 +226,45 @@ static const Value *GetLinearExpression(
break;
// FALL THROUGH.
case Instruction::Add:
- 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;
+ V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, Extension,
+ DL, Depth + 1, AC, DT);
+ Offset += RHSC->getValue();
+ return V;
case Instruction::Mul:
- V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, ZExtBits,
- SExtBits, DL, Depth + 1, AC, DT, NSW, NUW);
- Offset *= RHS;
- Scale *= RHS;
- break;
+ V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, Extension,
+ DL, Depth + 1, AC, DT);
+ Offset *= RHSC->getValue();
+ Scale *= RHSC->getValue();
+ return V;
case Instruction::Shl:
- 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;
+ V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, Extension,
+ DL, Depth + 1, AC, DT);
+ Offset <<= RHSC->getValue().getLimitedValue();
+ Scale <<= RHSC->getValue().getLimitedValue();
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) || isa<ZExtInst>(V)) {
+ if ((isa<SExtInst>(V) && Extension != EK_ZeroExt) ||
+ (isa<ZExtInst>(V) && Extension != EK_SignExt)) {
Value *CastOp = cast<CastInst>(V)->getOperand(0);
- unsigned NewWidth = V->getType()->getPrimitiveSizeInBits();
+ unsigned OldWidth = Scale.getBitWidth();
unsigned SmallWidth = CastOp->getType()->getPrimitiveSizeInBits();
- 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;
- }
+ 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);
+
+ // We have to sign-extend even if Extension == EK_ZeroExt as we can't
+ // decompose a sign extension (i.e. zext(x - 1) != zext(x) - zext(-1)).
+ Offset = Offset.sext(OldWidth);
return Result;
}
@@ -411,7 +346,7 @@ DecomposeGEPExpression(const Value *V, i
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) {
- const Value *Index = *I;
+ 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.
@@ -423,27 +358,25 @@ DecomposeGEPExpression(const Value *V, i
}
// For an array/pointer, add the element offset, explicitly scaled.
- if (const ConstantInt *CIdx = dyn_cast<ConstantInt>(Index)) {
+ if (ConstantInt *CIdx = dyn_cast<ConstantInt>(Index)) {
if (CIdx->isZero()) continue;
BaseOffs += DL.getTypeAllocSize(*GTI) * CIdx->getSExtValue();
continue;
}
uint64_t Scale = DL.getTypeAllocSize(*GTI);
- unsigned ZExtBits = 0, SExtBits = 0;
+ ExtensionKind Extension = EK_NotExtended;
// If the integer type is smaller than the pointer size, it is implicitly
// sign extended to pointer size.
unsigned Width = Index->getType()->getIntegerBitWidth();
- unsigned PointerSize = DL.getPointerSizeInBits(AS);
- if (PointerSize > Width)
- SExtBits += PointerSize - Width;
+ if (DL.getPointerSizeInBits(AS) > Width)
+ Extension = EK_SignExt;
// Use GetLinearExpression to decompose the index into a C1*V+C2 form.
APInt IndexScale(Width, 0), IndexOffset(Width, 0);
- bool NSW = true, NUW = true;
- Index = GetLinearExpression(Index, IndexScale, IndexOffset, ZExtBits,
- SExtBits, DL, 0, AC, DT, NSW, NUW);
+ Index = GetLinearExpression(Index, IndexScale, IndexOffset, Extension, DL,
+ 0, AC, DT);
// 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.
@@ -455,8 +388,8 @@ DecomposeGEPExpression(const Value *V, i
// 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].ZExtBits == ZExtBits &&
- VarIndices[i].SExtBits == SExtBits) {
+ if (VarIndices[i].V == Index &&
+ VarIndices[i].Extension == Extension) {
Scale += VarIndices[i].Scale;
VarIndices.erase(VarIndices.begin()+i);
break;
@@ -465,13 +398,13 @@ DecomposeGEPExpression(const Value *V, i
// Make sure that we have a scale that makes sense for this target's
// pointer size.
- if (unsigned ShiftBits = 64 - PointerSize) {
+ if (unsigned ShiftBits = 64 - DL.getPointerSizeInBits(AS)) {
Scale <<= ShiftBits;
Scale = (int64_t)Scale >> ShiftBits;
}
if (Scale) {
- VariableGEPIndex Entry = {Index, ZExtBits, SExtBits,
+ VariableGEPIndex Entry = {Index, Extension,
static_cast<int64_t>(Scale)};
VarIndices.push_back(Entry);
}
@@ -607,20 +540,6 @@ namespace {
/// is we say noalias(V, phi(VA, VB)) if noalias(V, VA) and noalias(V, VB).
bool isValueEqualInPotentialCycles(const Value *V1, const Value *V2);
- /// \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);
-
/// \brief Dest and Src are the variable indices from two decomposed
/// GetElementPtr instructions GEP1 and GEP2 which have common base
/// pointers. Subtract the GEP2 indices from GEP1 to find the symbolic
@@ -1017,60 +936,6 @@ static AliasResult aliasSameBasePointerG
return MayAlias;
}
-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;
-}
-
/// aliasGEP - Provide a bunch of ad-hoc rules to disambiguate a GEP instruction
/// against another pointer. We know that V1 is a GEP, but we don't know
/// anything about V2. UnderlyingV1 is GetUnderlyingObject(GEP1, DL),
@@ -1293,7 +1158,7 @@ AliasResult BasicAliasAnalysis::aliasGEP
// Zero-extension widens the variable, and so forces the sign
// bit to zero.
- bool IsZExt = GEP1VariableIndices[i].ZExtBits > 0 || isa<ZExtInst>(V);
+ bool IsZExt = GEP1VariableIndices[i].Extension == EK_ZeroExt;
SignKnownZero |= IsZExt;
SignKnownOne &= !IsZExt;
@@ -1323,10 +1188,6 @@ AliasResult BasicAliasAnalysis::aliasGEP
// 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
@@ -1666,14 +1527,14 @@ void BasicAliasAnalysis::GetIndexDiffere
for (unsigned i = 0, e = Src.size(); i != e; ++i) {
const Value *V = Src[i].V;
- unsigned ZExtBits = Src[i].ZExtBits, SExtBits = Src[i].SExtBits;
+ ExtensionKind Extension = Src[i].Extension;
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].ZExtBits != ZExtBits || Dest[j].SExtBits != SExtBits)
+ Dest[j].Extension != Extension)
continue;
// If we found it, subtract off Scale V's from the entry in Dest. If it
@@ -1688,7 +1549,7 @@ void BasicAliasAnalysis::GetIndexDiffere
// If we didn't consume this entry, add it to the end of the Dest list.
if (Scale) {
- VariableGEPIndex Entry = {V, ZExtBits, SExtBits, -Scale};
+ VariableGEPIndex Entry = { V, Extension, -Scale };
Dest.push_back(Entry);
}
}
Removed: llvm/trunk/test/Analysis/BasicAA/bug.23540.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/BasicAA/bug.23540.ll?rev=242024&view=auto
==============================================================================
--- llvm/trunk/test/Analysis/BasicAA/bug.23540.ll (original)
+++ llvm/trunk/test/Analysis/BasicAA/bug.23540.ll (removed)
@@ -1,17 +0,0 @@
-; 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
-}
-
Removed: llvm/trunk/test/Analysis/BasicAA/q.bad.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/BasicAA/q.bad.ll?rev=242024&view=auto
==============================================================================
--- llvm/trunk/test/Analysis/BasicAA/q.bad.ll (original)
+++ llvm/trunk/test/Analysis/BasicAA/q.bad.ll (removed)
@@ -1,180 +0,0 @@
-; 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
-}
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