/// isUsedInBasicBlock - Return true if this value is used in the specified
/// basic block.
bool Value::isUsedInBasicBlock(const BasicBlock *BB) const {
- // Start by scanning over the instructions looking for a use before we start
- // the expensive use iteration.
- unsigned MaxBlockSize = 3;
- for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
- if (std::find(I->op_begin(), I->op_end(), this) != I->op_end())
+ // This can be computed either by scanning the instructions in BB, or by
+ // scanning the use list of this Value. Both lists can be very long, but
+ // usually one is quite short.
+ //
+ // Scan both lists simultaneously until one is exhausted. This limits the
+ // search to the shorter list.
+ BasicBlock::const_iterator BI = BB->begin(), BE = BB->end();
+ const_use_iterator UI = use_begin(), UE = use_end();
+ for (; BI != BE && UI != UE; ++BI, ++UI) {
+ // Scan basic block: Check if this Value is used by the instruction at BI.
+ if (std::find(BI->op_begin(), BI->op_end(), this) != BI->op_end())
return true;
- if (--MaxBlockSize == 0) // If the block is larger fall back to use_iterator
- break;
- }
-
- if (MaxBlockSize != 0) // We scanned the entire block and found no use.
- return false;
-
- for (const_use_iterator I = use_begin(), E = use_end(); I != E; ++I) {
- const Instruction *User = dyn_cast<Instruction>(*I);
+ // Scan use list: Check if the use at UI is in BB.
+ const Instruction *User = dyn_cast<Instruction>(*UI);
if (User && User->getParent() == BB)
return true;
}
SmallString<256> NameData;
StringRef NameRef = NewName.toStringRef(NameData);
+ assert(NameRef.find_first_of(0) == StringRef::npos &&
+ "Null bytes are not allowed in names");
// Name isn't changing?
if (getName() == NameRef)
// Various metrics for how much to strip off of pointers.
enum PointerStripKind {
PSK_ZeroIndices,
+ PSK_ZeroIndicesAndAliases,
PSK_InBoundsConstantIndices,
PSK_InBounds
};
do {
if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
switch (StripKind) {
+ case PSK_ZeroIndicesAndAliases:
case PSK_ZeroIndices:
if (!GEP->hasAllZeroIndices())
return V;
break;
}
V = GEP->getPointerOperand();
- } else if (Operator::getOpcode(V) == Instruction::BitCast) {
+ } else if (Operator::getOpcode(V) == Instruction::BitCast ||
+ Operator::getOpcode(V) == Instruction::AddrSpaceCast) {
V = cast<Operator>(V)->getOperand(0);
} else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
- if (GA->mayBeOverridden())
+ if (StripKind == PSK_ZeroIndices || GA->mayBeOverridden())
return V;
V = GA->getAliasee();
} else {
} // namespace
Value *Value::stripPointerCasts() {
+ return stripPointerCastsAndOffsets<PSK_ZeroIndicesAndAliases>(this);
+}
+
+Value *Value::stripPointerCastsNoFollowAliases() {
return stripPointerCastsAndOffsets<PSK_ZeroIndices>(this);
}
return stripPointerCastsAndOffsets<PSK_InBoundsConstantIndices>(this);
}
+Value *Value::stripAndAccumulateInBoundsConstantOffsets(const DataLayout &DL,
+ APInt &Offset) {
+ if (!getType()->isPointerTy())
+ return this;
+
+ assert(Offset.getBitWidth() == DL.getPointerSizeInBits(cast<PointerType>(
+ getType())->getAddressSpace()) &&
+ "The offset must have exactly as many bits as our pointer.");
+
+ // Even though we don't look through PHI nodes, we could be called on an
+ // instruction in an unreachable block, which may be on a cycle.
+ SmallPtrSet<Value *, 4> Visited;
+ Visited.insert(this);
+ Value *V = this;
+ do {
+ if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
+ if (!GEP->isInBounds())
+ return V;
+ APInt GEPOffset(Offset);
+ if (!GEP->accumulateConstantOffset(DL, GEPOffset))
+ return V;
+ Offset = GEPOffset;
+ V = GEP->getPointerOperand();
+ } else if (Operator::getOpcode(V) == Instruction::BitCast) {
+ V = cast<Operator>(V)->getOperand(0);
+ } else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
+ V = GA->getAliasee();
+ } else {
+ return V;
+ }
+ assert(V->getType()->isPointerTy() && "Unexpected operand type!");
+ } while (Visited.insert(V));
+
+ return V;
+}
+
Value *Value::stripInBoundsOffsets() {
return stripPointerCastsAndOffsets<PSK_InBounds>(this);
}
#endif
}
-// Default implementation for CallbackVH.
-void CallbackVH::allUsesReplacedWith(Value *) {}
-
-void CallbackVH::deleted() {
- setValPtr(NULL);
-}
+// Pin the vtable to this file.
+void CallbackVH::anchor() {}