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FunctionAttrs: Merge attributes once instead of doing it for every argument.

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It has become an expensive operation. No functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184638 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Benjamin Kramer 2013-06-22 15:51:19 +00:00
parent 5c368899b3
commit 39bab0e11a
1 changed files with 47 additions and 33 deletions
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80
lib/Transforms/IPO/FunctionAttrs.cpp
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@ -410,9 +410,6 @@ bool FunctionAttrs::AddNoCaptureAttrs(const CallGraphSCC &SCC) {
ArgumentGraph AG;
AttrBuilder B;
B.addAttribute(Attribute::NoCapture);
// Check each function in turn, determining which pointer arguments are not
// captured.
for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) {
@ -427,43 +424,59 @@ bool FunctionAttrs::AddNoCaptureAttrs(const CallGraphSCC &SCC) {
if (F->isDeclaration() || F->mayBeOverridden())
continue;
SmallVector<AttributeSet, 8> AttrSets;
// Functions that are readonly (or readnone) and nounwind and don't return
// a value can't capture arguments. Don't analyze them.
if (F->onlyReadsMemory() && F->doesNotThrow() &&
F->getReturnType()->isVoidTy()) {
for (Function::arg_iterator A = F->arg_begin(), E = F->arg_end();
A != E; ++A) {
if (A->getType()->isPointerTy() && !A->hasNoCaptureAttr()) {
A->addAttr(AttributeSet::get(F->getContext(), A->getArgNo() + 1, B));
++NumNoCapture;
Changed = true;
}
}
continue;
}
for (Function::arg_iterator A = F->arg_begin(), E = F->arg_end(); A != E;
++A) {
if (!A->getType()->isPointerTy() || A->hasNoCaptureAttr())
continue;
AttributeSet In =
F->getAttributes().getParamAttributes(A->getArgNo() + 1);
AttrSets.push_back(In.addAttribute(F->getContext(), A->getArgNo() + 1,
Attribute::NoCapture));
}
} else {
for (Function::arg_iterator A = F->arg_begin(), E = F->arg_end(); A != E;
++A) {
if (!A->getType()->isPointerTy() || A->hasNoCaptureAttr())
continue;
for (Function::arg_iterator A = F->arg_begin(), E = F->arg_end(); A!=E; ++A)
if (A->getType()->isPointerTy() && !A->hasNoCaptureAttr()) {
ArgumentUsesTracker Tracker(SCCNodes);
PointerMayBeCaptured(A, &Tracker);
if (!Tracker.Captured) {
if (Tracker.Uses.empty()) {
// If it's trivially not captured, mark it nocapture now.
A->addAttr(AttributeSet::get(F->getContext(), A->getArgNo()+1, B));
++NumNoCapture;
Changed = true;
} else {
// If it's not trivially captured and not trivially not captured,
// then it must be calling into another function in our SCC. Save
// its particulars for Argument-SCC analysis later.
ArgumentGraphNode *Node = AG[A];
for (SmallVectorImpl<Argument*>::iterator UI = Tracker.Uses.begin(),
UE = Tracker.Uses.end(); UI != UE; ++UI)
Node->Uses.push_back(AG[*UI]);
}
if (Tracker.Captured)
continue; // It's captured. Don't bother doing SCC analysis on it.
if (Tracker.Uses.empty()) {
// If it's trivially not captured, mark it nocapture now.
AttributeSet In =
F->getAttributes().getParamAttributes(A->getArgNo() + 1);
AttrSets.push_back(In.addAttribute(F->getContext(), A->getArgNo() + 1,
Attribute::NoCapture));
} else {
// If it's not trivially captured and not trivially not captured,
// then it must be calling into another function in our SCC. Save
// its particulars for Argument-SCC analysis later.
ArgumentGraphNode *Node = AG[A];
for (SmallVectorImpl<Argument *>::iterator UI = Tracker.Uses.begin(),
UE = Tracker.Uses.end();
UI != UE; ++UI)
Node->Uses.push_back(AG[*UI]);
}
// Otherwise, it's captured. Don't bother doing SCC analysis on it.
}
}
// Merge all attribute sets into one in a single step.
if (!AttrSets.empty()) {
NumNoCapture += AttrSets.size();
AttrSets.push_back(F->getAttributes());
F->setAttributes(AttributeSet::get(F->getContext(), AttrSets));
Changed = true;
}
}
// The graph we've collected is partial because we stopped scanning for
@ -486,7 +499,7 @@ bool FunctionAttrs::AddNoCaptureAttrs(const CallGraphSCC &SCC) {
Definition->
addAttr(AttributeSet::get(ArgumentSCC[0]->Definition->getContext(),
ArgumentSCC[0]->Definition->getArgNo() + 1,
B));
Attribute::NoCapture));
++NumNoCapture;
Changed = true;
}
@ -528,7 +541,8 @@ bool FunctionAttrs::AddNoCaptureAttrs(const CallGraphSCC &SCC) {
for (unsigned i = 0, e = ArgumentSCC.size(); i != e; ++i) {
Argument *A = ArgumentSCC[i]->Definition;
A->addAttr(AttributeSet::get(A->getContext(), A->getArgNo() + 1, B));
A->addAttr(AttributeSet::get(A->getContext(), A->getArgNo() + 1,
Attribute::NoCapture));
++NumNoCapture;
Changed = true;
}