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| author | Bill Wendling <isanbard@gmail.com> | 2006-09-27 22:37:35 +0000 |
|---|---|---|
| committer | Bill Wendling <isanbard@gmail.com> | 2006-09-27 22:37:35 +0000 |
| commit | 4da1abb311b424d581cc1a67cde3aa0233da99b5 (patch) | |
| tree | 6bd87af5fa2d3f4b3820b4f1f5026a9cfd7c6597 | |
| parent | f38f543e01e50a38599b7fd718ca4480613ac611 (diff) | |
| download | external_llvm-4da1abb311b424d581cc1a67cde3aa0233da99b5.zip external_llvm-4da1abb311b424d581cc1a67cde3aa0233da99b5.tar.gz external_llvm-4da1abb311b424d581cc1a67cde3aa0233da99b5.tar.bz2 | |
Reapplying this patch. With the newest commits, the error in Olden/bisort
has disappeared.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30633 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/CodeGen/PHIElimination.cpp | 68 |
1 files changed, 44 insertions, 24 deletions
diff --git a/lib/CodeGen/PHIElimination.cpp b/lib/CodeGen/PHIElimination.cpp index 1cffca6..0314ae5 100644 --- a/lib/CodeGen/PHIElimination.cpp +++ b/lib/CodeGen/PHIElimination.cpp @@ -34,12 +34,15 @@ namespace { struct VISIBILITY_HIDDEN PNE : public MachineFunctionPass { bool runOnMachineFunction(MachineFunction &Fn) { + analyzePHINodes(Fn); + bool Changed = false; // Eliminate PHI instructions by inserting copies into predecessor blocks. for (MachineFunction::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I) Changed |= EliminatePHINodes(Fn, *I); + VRegPHIUseCount.clear(); return Changed; } @@ -54,15 +57,26 @@ namespace { /// bool EliminatePHINodes(MachineFunction &MF, MachineBasicBlock &MBB); void LowerAtomicPHINode(MachineBasicBlock &MBB, - MachineBasicBlock::iterator AfterPHIsIt, - DenseMap<unsigned, VirtReg2IndexFunctor> &VUC); + MachineBasicBlock::iterator AfterPHIsIt); + + /// analyzePHINodes - Gather information about the PHI nodes in + /// here. In particular, we want to map the number of uses of a virtual + /// register which is used in a PHI node. We map that to the BB the + /// vreg is coming from. This is used later to determine when the vreg + /// is killed in the BB. + /// + void analyzePHINodes(const MachineFunction& Fn); + + typedef std::pair<const MachineBasicBlock*, unsigned> BBVRegPair; + typedef std::map<BBVRegPair, unsigned> VRegPHIUse; + + VRegPHIUse VRegPHIUseCount; }; RegisterPass<PNE> X("phi-node-elimination", "Eliminate PHI nodes for register allocation"); } - const PassInfo *llvm::PHIEliminationID = X.getPassInfo(); /// EliminatePHINodes - Eliminate phi nodes by inserting copy instructions in @@ -72,20 +86,6 @@ bool PNE::EliminatePHINodes(MachineFunction &MF, MachineBasicBlock &MBB) { if (MBB.empty() || MBB.front().getOpcode() != TargetInstrInfo::PHI) return false; // Quick exit for basic blocks without PHIs. - // VRegPHIUseCount - Keep track of the number of times each virtual register - // is used by PHI nodes in successors of this block. - DenseMap<unsigned, VirtReg2IndexFunctor> VRegPHIUseCount; - VRegPHIUseCount.grow(MF.getSSARegMap()->getLastVirtReg()); - - for (MachineBasicBlock::pred_iterator PI = MBB.pred_begin(), - E = MBB.pred_end(); PI != E; ++PI) - for (MachineBasicBlock::succ_iterator SI = (*PI)->succ_begin(), - E = (*PI)->succ_end(); SI != E; ++SI) - for (MachineBasicBlock::iterator BBI = (*SI)->begin(), E = (*SI)->end(); - BBI != E && BBI->getOpcode() == TargetInstrInfo::PHI; ++BBI) - for (unsigned i = 1, e = BBI->getNumOperands(); i != e; i += 2) - VRegPHIUseCount[BBI->getOperand(i).getReg()]++; - // Get an iterator to the first instruction after the last PHI node (this may // also be the end of the basic block). MachineBasicBlock::iterator AfterPHIsIt = MBB.begin(); @@ -93,9 +93,9 @@ bool PNE::EliminatePHINodes(MachineFunction &MF, MachineBasicBlock &MBB) { AfterPHIsIt->getOpcode() == TargetInstrInfo::PHI) ++AfterPHIsIt; // Skip over all of the PHI nodes... - while (MBB.front().getOpcode() == TargetInstrInfo::PHI) { - LowerAtomicPHINode(MBB, AfterPHIsIt, VRegPHIUseCount); - } + while (MBB.front().getOpcode() == TargetInstrInfo::PHI) + LowerAtomicPHINode(MBB, AfterPHIsIt); + return true; } @@ -115,8 +115,7 @@ static bool InstructionUsesRegister(MachineInstr *MI, unsigned SrcReg) { /// atomic execution of PHIs. This lowering method is always correct all of the /// time. void PNE::LowerAtomicPHINode(MachineBasicBlock &MBB, - MachineBasicBlock::iterator AfterPHIsIt, - DenseMap<unsigned, VirtReg2IndexFunctor> &VRegPHIUseCount) { + MachineBasicBlock::iterator AfterPHIsIt) { // Unlink the PHI node from the basic block, but don't delete the PHI yet. MachineInstr *MPhi = MBB.remove(MBB.begin()); @@ -167,7 +166,9 @@ void PNE::LowerAtomicPHINode(MachineBasicBlock &MBB, // node. unsigned NumPreds = (MPhi->getNumOperands()-1)/2; for (unsigned i = 1; i != MPhi->getNumOperands(); i += 2) - VRegPHIUseCount[MPhi->getOperand(i).getReg()] -= NumPreds; + VRegPHIUseCount[BBVRegPair( + MPhi->getOperand(i + 1).getMachineBasicBlock(), + MPhi->getOperand(i).getReg())] -= NumPreds; // Now loop over all of the incoming arguments, changing them to copy into // the IncomingReg register in the corresponding predecessor basic block. @@ -219,7 +220,10 @@ void PNE::LowerAtomicPHINode(MachineBasicBlock &MBB, // // Is it used by any PHI instructions in this block? - bool ValueIsLive = VRegPHIUseCount[SrcReg] != 0; + bool ValueIsLive = + VRegPHIUseCount[BBVRegPair( + MPhi->getOperand(i).getMachineBasicBlock(), + SrcReg)] != 0; std::vector<MachineBasicBlock*> OpSuccBlocks; @@ -317,3 +321,19 @@ void PNE::LowerAtomicPHINode(MachineBasicBlock &MBB, delete MPhi; ++NumAtomic; } + +/// analyzePHINodes - Gather information about the PHI nodes in here. In +/// particular, we want to map the number of uses of a virtual register which is +/// used in a PHI node. We map that to the BB the vreg is coming from. This is +/// used later to determine when the vreg is killed in the BB. +/// +void PNE::analyzePHINodes(const MachineFunction& Fn) { + for (MachineFunction::const_iterator I = Fn.begin(), E = Fn.end(); + I != E; ++I) + for (MachineBasicBlock::const_iterator BBI = I->begin(), BBE = I->end(); + BBI != BBE && BBI->getOpcode() == TargetInstrInfo::PHI; ++BBI) + for (unsigned i = 1, e = BBI->getNumOperands(); i != e; i += 2) + VRegPHIUseCount[BBVRegPair( + BBI->getOperand(i + 1).getMachineBasicBlock(), + BBI->getOperand(i).getReg())]++; +} |