#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/AssumptionTracker.h"
#include "llvm/Analysis/CFG.h"
#include "llvm/Analysis/CaptureTracking.h"
#include "llvm/Analysis/InstructionSimplify.h"
/// represented in the result.
static Value *GetLinearExpression(Value *V, APInt &Scale, APInt &Offset,
ExtensionKind &Extension,
- const DataLayout &DL, unsigned Depth) {
+ const DataLayout &DL, unsigned Depth,
+ AssumptionTracker *AT,
+ DominatorTree *DT) {
assert(V->getType()->isIntegerTy() && "Not an integer value");
// Limit our recursion depth.
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))
+ if (!MaskedValueIsZero(BOp->getOperand(0), RHSC->getValue(), &DL, 0,
+ AT, BOp, DT))
break;
// FALL THROUGH.
case Instruction::Add:
V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, Extension,
- DL, Depth+1);
+ DL, Depth+1, AT, DT);
Offset += RHSC->getValue();
return V;
case Instruction::Mul:
V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, Extension,
- DL, Depth+1);
+ DL, Depth+1, AT, DT);
Offset *= RHSC->getValue();
Scale *= RHSC->getValue();
return V;
case Instruction::Shl:
V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, Extension,
- DL, Depth+1);
+ DL, Depth+1, AT, DT);
Offset <<= RHSC->getValue().getLimitedValue();
Scale <<= RHSC->getValue().getLimitedValue();
return V;
Extension = isa<SExtInst>(V) ? EK_SignExt : EK_ZeroExt;
Value *Result = GetLinearExpression(CastOp, Scale, Offset, Extension,
- DL, Depth+1);
+ DL, Depth+1, AT, DT);
Scale = Scale.zext(OldWidth);
Offset = Offset.zext(OldWidth);
static const Value *
DecomposeGEPExpression(const Value *V, int64_t &BaseOffs,
SmallVectorImpl<VariableGEPIndex> &VarIndices,
- bool &MaxLookupReached, const DataLayout *DL) {
+ bool &MaxLookupReached, const DataLayout *DL,
+ AssumptionTracker *AT, DominatorTree *DT) {
// Limit recursion depth to limit compile time in crazy cases.
unsigned MaxLookup = MaxLookupSearchDepth;
MaxLookupReached = false;
// If it's not a GEP, hand it off to SimplifyInstruction to see if it
// can come up with something. This matches what GetUnderlyingObject does.
if (const Instruction *I = dyn_cast<Instruction>(V))
- // TODO: Get a DominatorTree and use it here.
+ // TODO: Get a DominatorTree and AssumptionTracker and use them here
+ // (these are both now available in this function, but this should be
+ // updated when GetUnderlyingObject is updated). TLI should be
+ // provided also.
if (const Value *Simplified =
SimplifyInstruction(const_cast<Instruction *>(I), DL)) {
V = Simplified;
// 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);
+ *DL, 0, AT, 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.
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addRequired<AliasAnalysis>();
+ AU.addRequired<AssumptionTracker>();
AU.addRequired<TargetLibraryInfo>();
}
const Location &Loc) override;
ModRefResult getModRefInfo(ImmutableCallSite CS1,
- ImmutableCallSite CS2) override {
- // The AliasAnalysis base class has some smarts, lets use them.
- return AliasAnalysis::getModRefInfo(CS1, CS2);
- }
+ ImmutableCallSite CS2) override;
/// pointsToConstantMemory - Chase pointers until we find a (constant
/// global) or not.
INITIALIZE_AG_PASS_BEGIN(BasicAliasAnalysis, AliasAnalysis, "basicaa",
"Basic Alias Analysis (stateless AA impl)",
false, true, false)
+INITIALIZE_PASS_DEPENDENCY(AssumptionTracker)
INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfo)
INITIALIZE_AG_PASS_END(BasicAliasAnalysis, AliasAnalysis, "basicaa",
"Basic Alias Analysis (stateless AA impl)",
return Loc;
}
+static bool isAssumeIntrinsic(ImmutableCallSite CS) {
+ const IntrinsicInst *II = dyn_cast<IntrinsicInst>(CS.getInstruction());
+ if (II && II->getIntrinsicID() == Intrinsic::assume)
+ return true;
+
+ return false;
+}
+
/// getModRefInfo - Check to see if the specified callsite can clobber the
/// specified memory object. Since we only look at local properties of this
/// function, we really can't say much about this query. We do, however, use
return NoModRef;
}
+ // While the assume intrinsic is marked as arbitrarily writing so that
+ // proper control dependencies will be maintained, it never aliases any
+ // particular memory location.
+ if (isAssumeIntrinsic(CS))
+ return NoModRef;
+
// The AliasAnalysis base class has some smarts, lets use them.
return AliasAnalysis::getModRefInfo(CS, Loc);
}
+AliasAnalysis::ModRefResult
+BasicAliasAnalysis::getModRefInfo(ImmutableCallSite CS1,
+ ImmutableCallSite CS2) {
+ // While the assume intrinsic is marked as arbitrarily writing so that
+ // proper control dependencies will be maintained, it never aliases any
+ // particular memory location.
+ if (isAssumeIntrinsic(CS1) || isAssumeIntrinsic(CS2))
+ return NoModRef;
+
+ // The AliasAnalysis base class has some smarts, lets use them.
+ return AliasAnalysis::getModRefInfo(CS1, CS2);
+}
+
/// 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),
bool GEP1MaxLookupReached;
SmallVector<VariableGEPIndex, 4> GEP1VariableIndices;
+ AssumptionTracker *AT = &getAnalysis<AssumptionTracker>();
+ DominatorTreeWrapperPass *DTWP =
+ getAnalysisIfAvailable<DominatorTreeWrapperPass>();
+ DominatorTree *DT = DTWP ? &DTWP->getDomTree() : nullptr;
+
// If we have two gep instructions with must-alias or not-alias'ing base
// pointers, figure out if the indexes to the GEP tell us anything about the
// derived pointer.
SmallVector<VariableGEPIndex, 4> GEP2VariableIndices;
const Value *GEP2BasePtr =
DecomposeGEPExpression(GEP2, GEP2BaseOffset, GEP2VariableIndices,
- GEP2MaxLookupReached, DL);
+ GEP2MaxLookupReached, DL, AT, DT);
const Value *GEP1BasePtr =
DecomposeGEPExpression(GEP1, GEP1BaseOffset, GEP1VariableIndices,
- GEP1MaxLookupReached, DL);
+ GEP1MaxLookupReached, DL, AT, DT);
// DecomposeGEPExpression and GetUnderlyingObject should return the
// same result except when DecomposeGEPExpression has no DataLayout.
if (GEP1BasePtr != UnderlyingV1 || GEP2BasePtr != UnderlyingV2) {
// about the relation of the resulting pointer.
const Value *GEP1BasePtr =
DecomposeGEPExpression(GEP1, GEP1BaseOffset, GEP1VariableIndices,
- GEP1MaxLookupReached, DL);
+ GEP1MaxLookupReached, DL, AT, DT);
int64_t GEP2BaseOffset;
bool GEP2MaxLookupReached;
SmallVector<VariableGEPIndex, 4> GEP2VariableIndices;
const Value *GEP2BasePtr =
DecomposeGEPExpression(GEP2, GEP2BaseOffset, GEP2VariableIndices,
- GEP2MaxLookupReached, DL);
+ GEP2MaxLookupReached, DL, AT, DT);
// DecomposeGEPExpression and GetUnderlyingObject should return the
// same result except when DecomposeGEPExpression has no DataLayout.
const Value *GEP1BasePtr =
DecomposeGEPExpression(GEP1, GEP1BaseOffset, GEP1VariableIndices,
- GEP1MaxLookupReached, DL);
+ GEP1MaxLookupReached, DL, AT, DT);
// DecomposeGEPExpression and GetUnderlyingObject should return the
// same result except when DecomposeGEPExpression has no DataLayout.
// Make sure that the visited phis cannot reach the Value. This ensures that
// the Values cannot come from different iterations of a potential cycle the
// phi nodes could be involved in.
- for (SmallPtrSet<const BasicBlock *, 8>::iterator PI = VisitedPhiBBs.begin(),
- PE = VisitedPhiBBs.end();
- PI != PE; ++PI)
- if (isPotentiallyReachable((*PI)->begin(), Inst, DT, LI))
+ for (auto *P : VisitedPhiBBs)
+ if (isPotentiallyReachable(P->begin(), Inst, DT, LI))
return false;
return true;
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