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Break critical edges coming into blocks with PHI nodes.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44019 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Owen Anderson 2007-11-12 17:27:27 +00:00
parent bb310f1b9b
commit 35e2dba672
1 changed files with 26 additions and 0 deletions
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26
lib/CodeGen/StrongPHIElimination.cpp
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@ -93,6 +93,7 @@ namespace {
void processBlock(MachineBasicBlock* MBB);
std::vector<DomForestNode*> computeDomForest(std::set<unsigned>& instrs);
void breakCriticalEdges(MachineFunction &Fn);
};
@ -295,7 +296,32 @@ void StrongPHIElimination::processBlock(MachineBasicBlock* MBB) {
}
}
void StrongPHIElimination::breakCriticalEdges(MachineFunction &Fn) {
typedef std::pair<MachineBasicBlock*, MachineBasicBlock*> MBB_pair;
MachineDominatorTree& MDT = getAnalysis<MachineDominatorTree>();
//LiveVariables& LV = getAnalysis<LiveVariables>();
std::vector<MBB_pair> criticals;
for (MachineFunction::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I)
if (!I->empty() &&
I->begin()->getOpcode() == TargetInstrInfo::PHI &&
I->pred_size() > 1)
for (MachineBasicBlock::pred_iterator PI = I->pred_begin(),
PE = I->pred_end(); PI != PE; ++PI)
if ((*PI)->succ_size() > 1)
criticals.push_back(std::make_pair(*PI, I));
for (std::vector<MBB_pair>::iterator I = criticals.begin(),
E = criticals.end(); I != E; ++I) {
SplitCriticalMachineEdge(I->first, I->second);
MDT.splitBlock(I->first);
}
}
bool StrongPHIElimination::runOnMachineFunction(MachineFunction &Fn) {
breakCriticalEdges(Fn);
computeDFS(Fn);
for (MachineFunction::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I)