diff options
Diffstat (limited to 'lib/CodeGen/RegAlloc/PhyRegAlloc.cpp')
| -rw-r--r-- | lib/CodeGen/RegAlloc/PhyRegAlloc.cpp | 84 |
1 files changed, 73 insertions, 11 deletions
diff --git a/lib/CodeGen/RegAlloc/PhyRegAlloc.cpp b/lib/CodeGen/RegAlloc/PhyRegAlloc.cpp index bd87ec91aa..c97028a683 100644 --- a/lib/CodeGen/RegAlloc/PhyRegAlloc.cpp +++ b/lib/CodeGen/RegAlloc/PhyRegAlloc.cpp @@ -419,6 +419,32 @@ void PhyRegAlloc::addInterferencesForArgs() { // Utility functions used below //----------------------------- inline void +InsertBefore(MachineInstr* newMI, + MachineCodeForBasicBlock& MIVec, + MachineCodeForBasicBlock::iterator& MII) +{ + MII = MIVec.insert(MII, newMI); + ++MII; +} + +inline void +InsertAfter(MachineInstr* newMI, + MachineCodeForBasicBlock& MIVec, + MachineCodeForBasicBlock::iterator& MII) +{ + ++MII; // insert before the next instruction + MII = MIVec.insert(MII, newMI); +} + +inline void +SubstituteInPlace(MachineInstr* newMI, + MachineCodeForBasicBlock& MIVec, + MachineCodeForBasicBlock::iterator MII) +{ + *MII = newMI; +} + +inline void PrependInstructions(vector<MachineInstr *> &IBef, MachineCodeForBasicBlock& MIVec, MachineCodeForBasicBlock::iterator& MII, @@ -434,8 +460,7 @@ PrependInstructions(vector<MachineInstr *> &IBef, if (OrigMI) cerr << "For MInst:\n " << *OrigMI; cerr << msg << "PREPENDed instr:\n " << **AdIt << "\n"; } - MII = MIVec.insert(MII, *AdIt); - ++MII; + InsertBefore(*AdIt, MIVec, MII); } } } @@ -456,8 +481,7 @@ AppendInstructions(std::vector<MachineInstr *> &IAft, if (OrigMI) cerr << "For MInst:\n " << *OrigMI; cerr << msg << "APPENDed instr:\n " << **AdIt << "\n"; } - ++MII; // insert before the next instruction - MII = MIVec.insert(MII, *AdIt); + InsertAfter(*AdIt, MIVec, MII); } } } @@ -477,7 +501,7 @@ void PhyRegAlloc::updateMachineCode() for (Function::const_iterator BBI = Meth->begin(), BBE = Meth->end(); BBI != BBE; ++BBI) { - + // iterate over all the machine instructions in BB MachineCodeForBasicBlock &MIVec = MachineCodeForBasicBlock::get(BBI); for (MachineCodeForBasicBlock::iterator MII = MIVec.begin(); @@ -538,13 +562,38 @@ void PhyRegAlloc::updateMachineCode() insertCode4SpilledLR(LR, MInst, BBI, OpNum ); } } // for each operand - - + // Now add instructions that the register allocator inserts before/after // this machine instructions (done only for calls/rets/incoming args) // We do this here, to ensure that spill for an instruction is inserted // closest as possible to an instruction (see above insertCode4Spill...) // + // First, if the instruction in the delay slot of a branch needs + // instructions inserted, move it out of the delay slot and before the + // branch because putting code before or after it would be VERY BAD! + // + unsigned bumpIteratorBy = 0; + if (MII != MIVec.begin()) + if (unsigned predDelaySlots = + TM.getInstrInfo().getNumDelaySlots((*(MII-1))->getOpCode())) + { + assert(predDelaySlots==1 && "Not handling multiple delay slots!"); + if (TM.getInstrInfo().isBranch((*(MII-1))->getOpCode()) + && (AddedInstrMap.count(MInst) || + AddedInstrMap[MInst].InstrnsAfter.size() > 0)) + { + // Current instruction is in the delay slot of a branch and it + // needs spill code inserted before or after it. + // Move it before the preceding branch. + InsertBefore(MInst, MIVec, --MII); + MachineInstr* nopI = + new MachineInstr(TM.getInstrInfo().getNOPOpCode()); + SubstituteInPlace(nopI, MIVec, MII+1); // replace orig with NOP + --MII; // point to MInst in new location + bumpIteratorBy = 2; // later skip the branch and the NOP! + } + } + // If there are instructions to be added, *before* this machine // instruction, add them now. // @@ -561,9 +610,18 @@ void PhyRegAlloc::updateMachineCode() // added after it must really go after the delayed instruction(s) // So, we move the InstrAfter of the current instruction to the // corresponding delayed instruction - - unsigned delay; - if ((delay=TM.getInstrInfo().getNumDelaySlots(MInst->getOpCode())) >0){ + if (unsigned delay = + TM.getInstrInfo().getNumDelaySlots(MInst->getOpCode())) { + + // Delayed instructions are typically branches or calls. Let's make + // sure this is not a branch, otherwise "insert-after" is meaningless, + // and should never happen for any reason (spill code, register + // restores, etc.). + assert(! TM.getInstrInfo().isBranch(MInst->getOpCode()) && + ! TM.getInstrInfo().isReturn(MInst->getOpCode()) && + "INTERNAL ERROR: Register allocator should not be inserting " + "any code after a branch or return!"); + move2DelayedInstr(MInst, *(MII+delay) ); } else { @@ -572,7 +630,11 @@ void PhyRegAlloc::updateMachineCode() AppendInstructions(AddedInstrMap[MInst].InstrnsAfter, MIVec, MII,""); } // if not delay } - + + // If we mucked with the instruction order above, adjust the loop iterator + if (bumpIteratorBy) + MII = MII + bumpIteratorBy; + } // for each machine instruction } } |