diff options
Diffstat (limited to 'lib/CodeGen/PHIElimination.h')
-rw-r--r-- | lib/CodeGen/PHIElimination.h | 72 |
1 files changed, 20 insertions, 52 deletions
diff --git a/lib/CodeGen/PHIElimination.h b/lib/CodeGen/PHIElimination.h index 895aaa4..7dedf03 100644 --- a/lib/CodeGen/PHIElimination.h +++ b/lib/CodeGen/PHIElimination.h @@ -22,17 +22,8 @@ namespace llvm { /// Lower PHI instructions to copies. class PHIElimination : public MachineFunctionPass { MachineRegisterInfo *MRI; // Machine register information - private: - - typedef SmallSet<MachineBasicBlock*, 4> PHIKillList; - typedef DenseMap<unsigned, PHIKillList> PHIKillMap; - typedef DenseMap<unsigned, MachineBasicBlock*> PHIDefMap; public: - - typedef PHIKillList::iterator phi_kill_iterator; - typedef PHIKillList::const_iterator const_phi_kill_iterator; - static char ID; // Pass identification, replacement for typeid PHIElimination() : MachineFunctionPass(&ID) {} @@ -40,38 +31,6 @@ namespace llvm { virtual void getAnalysisUsage(AnalysisUsage &AU) const; - /// Return true if the given vreg was defined by a PHI intsr prior to - /// lowering. - bool hasPHIDef(unsigned vreg) const { - return PHIDefs.count(vreg); - } - - /// Returns the block in which the PHI instruction which defined the - /// given vreg used to reside. - MachineBasicBlock* getPHIDefBlock(unsigned vreg) { - PHIDefMap::iterator phiDefItr = PHIDefs.find(vreg); - assert(phiDefItr != PHIDefs.end() && "vreg has no phi-def."); - return phiDefItr->second; - } - - /// Returns true if the given vreg was killed by a PHI instr. - bool hasPHIKills(unsigned vreg) const { - return PHIKills.count(vreg); - } - - /// Returns an iterator over the BasicBlocks which contained PHI - /// kills of this register prior to lowering. - phi_kill_iterator phiKillsBegin(unsigned vreg) { - PHIKillMap::iterator phiKillItr = PHIKills.find(vreg); - assert(phiKillItr != PHIKills.end() && "vreg has no phi-kills."); - return phiKillItr->second.begin(); - } - phi_kill_iterator phiKillsEnd(unsigned vreg) { - PHIKillMap::iterator phiKillItr = PHIKills.find(vreg); - assert(phiKillItr != PHIKills.end() && "vreg has no phi-kills."); - return phiKillItr->second.end(); - } - private: /// EliminatePHINodes - Eliminate phi nodes by inserting copy instructions /// in predecessor basic blocks. @@ -109,12 +68,29 @@ namespace llvm { // SkipPHIsAndLabels - Copies need to be inserted after phi nodes and // also after any exception handling labels: in landing pads execution // starts at the label, so any copies placed before it won't be executed! + // We also deal with DBG_VALUEs, which are a bit tricky: + // PHI + // DBG_VALUE + // LABEL + // Here the DBG_VALUE needs to be skipped, and if it refers to a PHI it + // needs to be annulled or, better, moved to follow the label, as well. + // PHI + // DBG_VALUE + // no label + // Here it is not a good idea to skip the DBG_VALUE. + // FIXME: For now we skip and annul all DBG_VALUEs, maximally simple and + // maximally stupid. MachineBasicBlock::iterator SkipPHIsAndLabels(MachineBasicBlock &MBB, MachineBasicBlock::iterator I) { // Rather than assuming that EH labels come before other kinds of labels, // just skip all labels. - while (I != MBB.end() && (I->isPHI() || I->isLabel())) + while (I != MBB.end() && + (I->isPHI() || I->isLabel() || I->isDebugValue())) { + if (I->isDebugValue() && I->getNumOperands()==3 && + I->getOperand(0).isReg()) + I->getOperand(0).setReg(0U); ++I; + } return I; } @@ -122,21 +98,13 @@ namespace llvm { typedef DenseMap<BBVRegPair, unsigned> VRegPHIUse; VRegPHIUse VRegPHIUseCount; - PHIDefMap PHIDefs; - PHIKillMap PHIKills; // Defs of PHI sources which are implicit_def. SmallPtrSet<MachineInstr*, 4> ImpDefs; - // Lowered PHI nodes may be reused. We provide special DenseMap traits to - // match PHI nodes with identical arguments. - struct PHINodeTraits : public DenseMapInfo<MachineInstr*> { - static unsigned getHashValue(const MachineInstr *PtrVal); - static bool isEqual(const MachineInstr *LHS, const MachineInstr *RHS); - }; - // Map reusable lowered PHI node -> incoming join register. - typedef DenseMap<MachineInstr*, unsigned, PHINodeTraits> LoweredPHIMap; + typedef DenseMap<MachineInstr*, unsigned, + MachineInstrExpressionTrait> LoweredPHIMap; LoweredPHIMap LoweredPHIs; }; |