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performance: get rid of repeated dereferencing of use_iterator by caching its result

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100547 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Gabor Greif 2010-04-06 19:14:05 +00:00
parent 0b520db74d
commit a01d6db569
1 changed files with 28 additions and 21 deletions
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49
lib/Transforms/IPO/GlobalOpt.cpp
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@ -612,40 +612,44 @@ static GlobalVariable *SRAGlobal(GlobalVariable *GV, const TargetData &TD) {
/// phi nodes we've seen to avoid reprocessing them.
static bool AllUsesOfValueWillTrapIfNull(Value *V,
SmallPtrSet<PHINode*, 8> &PHIs) {
for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E; ++UI)
if (isa<LoadInst>(*UI)) {
for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E;
++UI) {
User *U = *UI;
if (isa<LoadInst>(U)) {
// Will trap.
} else if (StoreInst *SI = dyn_cast<StoreInst>(*UI)) {
} else if (StoreInst *SI = dyn_cast<StoreInst>(U)) {
if (SI->getOperand(0) == V) {
//cerr << "NONTRAPPING USE: " << **UI;
//cerr << "NONTRAPPING USE: " << *U;
return false; // Storing the value.
}
} else if (CallInst *CI = dyn_cast<CallInst>(*UI)) {
} else if (CallInst *CI = dyn_cast<CallInst>(U)) {
if (CI->getCalledValue() != V) {
//cerr << "NONTRAPPING USE: " << **UI;
//cerr << "NONTRAPPING USE: " << *U;
return false; // Not calling the ptr
}
} else if (InvokeInst *II = dyn_cast<InvokeInst>(*UI)) {
} else if (InvokeInst *II = dyn_cast<InvokeInst>(U)) {
if (II->getCalledValue() != V) {
//cerr << "NONTRAPPING USE: " << **UI;
//cerr << "NONTRAPPING USE: " << *U;
return false; // Not calling the ptr
}
} else if (BitCastInst *CI = dyn_cast<BitCastInst>(*UI)) {
} else if (BitCastInst *CI = dyn_cast<BitCastInst>(U)) {
if (!AllUsesOfValueWillTrapIfNull(CI, PHIs)) return false;
} else if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(*UI)) {
} else if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(U)) {
if (!AllUsesOfValueWillTrapIfNull(GEPI, PHIs)) return false;
} else if (PHINode *PN = dyn_cast<PHINode>(*UI)) {
} else if (PHINode *PN = dyn_cast<PHINode>(U)) {
// If we've already seen this phi node, ignore it, it has already been
// checked.
if (PHIs.insert(PN) && !AllUsesOfValueWillTrapIfNull(PN, PHIs))
return false;
} else if (isa<ICmpInst>(*UI) &&
} else if (isa<ICmpInst>(U) &&
isa<ConstantPointerNull>(UI->getOperand(1))) {
// Ignore icmp X, null
} else {
//cerr << "NONTRAPPING USE: " << **UI;
//cerr << "NONTRAPPING USE: " << *U;
return false;
}
}
return true;
}
@ -653,19 +657,22 @@ static bool AllUsesOfValueWillTrapIfNull(Value *V,
/// from GV will trap if the loaded value is null. Note that this also permits
/// comparisons of the loaded value against null, as a special case.
static bool AllUsesOfLoadedValueWillTrapIfNull(GlobalVariable *GV) {
for (Value::use_iterator UI = GV->use_begin(), E = GV->use_end(); UI!=E; ++UI)
if (LoadInst *LI = dyn_cast<LoadInst>(*UI)) {
for (Value::use_iterator UI = GV->use_begin(), E = GV->use_end();
UI != E; ++UI) {
User *U = *UI;
if (LoadInst *LI = dyn_cast<LoadInst>(U)) {
SmallPtrSet<PHINode*, 8> PHIs;
if (!AllUsesOfValueWillTrapIfNull(LI, PHIs))
return false;
} else if (isa<StoreInst>(*UI)) {
} else if (isa<StoreInst>(U)) {
// Ignore stores to the global.
} else {
// We don't know or understand this user, bail out.
//cerr << "UNKNOWN USER OF GLOBAL!: " << **UI;
//cerr << "UNKNOWN USER OF GLOBAL!: " << *U;
return false;
}
}
return true;
}
@ -941,11 +948,11 @@ static GlobalVariable *OptimizeGlobalAddressOfMalloc(GlobalVariable *GV,
/// it is to the specified global.
static bool ValueIsOnlyUsedLocallyOrStoredToOneGlobal(const Instruction *V,
const GlobalVariable *GV,
SmallPtrSet<const PHINode*, 8> &PHIs) {
SmallPtrSet<const PHINode*, 8> &PHIs) {
for (Value::const_use_iterator UI = V->use_begin(), E = V->use_end();
UI != E;++UI){
UI != E; ++UI) {
const Instruction *Inst = cast<Instruction>(*UI);
if (isa<LoadInst>(Inst) || isa<CmpInst>(Inst)) {
continue; // Fine, ignore.
}