Remove critical edge breaking. It won't be necessary as long as we are very careful when inserting copies.

llvm-svn: 45309
This commit is contained in:
Owen Anderson 2007-12-22 04:50:11 +00:00
parent 8f4ec948d3
commit f3765d08f8

View File

@ -21,7 +21,6 @@
#define DEBUG_TYPE "strongphielim"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/BreakCriticalMachineEdge.h"
#include "llvm/CodeGen/LiveVariables.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
@ -101,7 +100,6 @@ namespace {
std::set<unsigned>& PHIUnion,
std::vector<StrongPHIElimination::DomForestNode*>& DF,
std::vector<std::pair<unsigned, unsigned> >& locals);
void breakCriticalEdges(MachineFunction &Fn);
};
@ -501,42 +499,7 @@ void StrongPHIElimination::processPHIUnion(MachineInstr* Inst,
}
}
/// breakCriticalEdges - Break critical edges coming into blocks with PHI
/// nodes, preserving dominator and livevariable info.
void StrongPHIElimination::breakCriticalEdges(MachineFunction &Fn) {
typedef std::pair<MachineBasicBlock*, MachineBasicBlock*> MBB_pair;
MachineDominatorTree& MDT = getAnalysis<MachineDominatorTree>();
LiveVariables& LV = getAnalysis<LiveVariables>();
// Find critical edges
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) {
// Split the edge
MachineBasicBlock* new_bb = SplitCriticalMachineEdge(I->first, I->second);
// Update dominators
MDT.splitBlock(I->first);
// Update livevariables
for (unsigned var = 1024; var < Fn.getSSARegMap()->getLastVirtReg(); ++var)
if (isLiveOut(LV.getVarInfo(var), I->first))
LV.getVarInfo(var).AliveBlocks.set(new_bb->getNumber());
}
}
bool StrongPHIElimination::runOnMachineFunction(MachineFunction &Fn) {
breakCriticalEdges(Fn);
computeDFS(Fn);
for (MachineFunction::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I)