diff --git a/lib/CodeGen/RegAllocSimple.cpp b/lib/CodeGen/RegAllocSimple.cpp index 3d1a32b27a0..104d042de09 100644 --- a/lib/CodeGen/RegAllocSimple.cpp +++ b/lib/CodeGen/RegAllocSimple.cpp @@ -7,6 +7,7 @@ // //===----------------------------------------------------------------------===// +#include "llvm/CodeGen/Passes.h" #include "llvm/CodeGen/MachineFunctionPass.h" #include "llvm/CodeGen/MachineInstr.h" #include "llvm/CodeGen/SSARegMap.h" @@ -46,14 +47,14 @@ namespace { /// runOnMachineFunction - Register allocate the whole function bool runOnMachineFunction(MachineFunction &Fn); + virtual void getAnalysisUsage(AnalysisUsage &AU) const { + AU.addRequiredID(PHIEliminationID); // Eliminate PHI nodes + MachineFunctionPass::getAnalysisUsage(AU); + } private: /// AllocateBasicBlock - Register allocate the specified basic block. void AllocateBasicBlock(MachineBasicBlock &MBB); - /// EliminatePHINodes - Eliminate phi nodes by inserting copy instructions - /// in predecessor basic blocks. - void EliminatePHINodes(MachineBasicBlock &MBB); - /// getStackSpaceFor - This returns the offset of the specified virtual /// register on the stack, allocating space if neccesary. int getStackSpaceFor(unsigned VirtReg, const TargetRegisterClass *RC); @@ -88,8 +89,7 @@ int RegAllocSimple::getStackSpaceFor(unsigned VirtReg, return I->second; // Already has space allocated? // Allocate a new stack object for this spill location... - int FrameIdx = - MF->getFrameInfo()->CreateStackObject(RC->getSize(), RC->getAlignment()); + int FrameIdx = MF->getFrameInfo()->CreateStackObject(RC); // Assign the slot... StackSlotForVirtReg.insert(I, std::make_pair(VirtReg, FrameIdx)); @@ -137,74 +137,6 @@ void RegAllocSimple::spillVirtReg(MachineBasicBlock &MBB, } -/// EliminatePHINodes - Eliminate phi nodes by inserting copy instructions in -/// predecessor basic blocks. -/// -void RegAllocSimple::EliminatePHINodes(MachineBasicBlock &MBB) { - const MachineInstrInfo &MII = TM->getInstrInfo(); - - while (MBB.front()->getOpcode() == MachineInstrInfo::PHI) { - MachineInstr *MI = MBB.front(); - // Unlink the PHI node from the basic block... but don't delete the PHI yet - MBB.erase(MBB.begin()); - - DEBUG(std::cerr << "num ops: " << MI->getNumOperands() << "\n"); - assert(MI->getOperand(0).isVirtualRegister() && - "PHI node doesn't write virt reg?"); - - unsigned virtualReg = MI->getOperand(0).getAllocatedRegNum(); - - for (int i = MI->getNumOperands() - 1; i >= 2; i-=2) { - MachineOperand &opVal = MI->getOperand(i-1); - - // Get the MachineBasicBlock equivalent of the BasicBlock that is the - // source path the phi - MachineBasicBlock &opBlock = *MI->getOperand(i).getMachineBasicBlock(); - - // Check to make sure we haven't already emitted the copy for this block. - // This can happen because PHI nodes may have multiple entries for the - // same basic block. It doesn't matter which entry we use though, because - // all incoming values are guaranteed to be the same for a particular bb. - // - // Note that this is N^2 in the number of phi node entries, but since the - // # of entries is tiny, this is not a problem. - // - bool HaveNotEmitted = true; - for (int op = MI->getNumOperands() - 1; op != i; op -= 2) - if (&opBlock == MI->getOperand(op).getMachineBasicBlock()) { - HaveNotEmitted = false; - break; - } - - if (HaveNotEmitted) { - MachineBasicBlock::iterator opI = opBlock.end(); - MachineInstr *opMI = *--opI; - - // must backtrack over ALL the branches in the previous block - while (MII.isBranch(opMI->getOpcode()) && opI != opBlock.begin()) - opMI = *--opI; - - // move back to the first branch instruction so new instructions - // are inserted right in front of it and not in front of a non-branch - // - if (!MII.isBranch(opMI->getOpcode())) - ++opI; - - const TargetRegisterClass *RC = - MF->getSSARegMap()->getRegClass(virtualReg); - - assert(opVal.isVirtualRegister() && - "Machine PHI Operands must all be virtual registers!"); - RegInfo->copyRegToReg(opBlock, opI, virtualReg, opVal.getReg(), RC); - } - } - - // really delete the PHI instruction now! - delete MI; - } -} - - void RegAllocSimple::AllocateBasicBlock(MachineBasicBlock &MBB) { // loop over each instruction for (MachineBasicBlock::iterator I = MBB.begin(); I != MBB.end(); ++I) { @@ -281,12 +213,6 @@ bool RegAllocSimple::runOnMachineFunction(MachineFunction &Fn) { TM = &MF->getTarget(); RegInfo = TM->getRegisterInfo(); - // First pass: eliminate PHI instructions by inserting copies into predecessor - // blocks. - for (MachineFunction::iterator MBB = Fn.begin(), MBBe = Fn.end(); - MBB != MBBe; ++MBB) - EliminatePHINodes(*MBB); - // Loop over all of the basic blocks, eliminating virtual register references for (MachineFunction::iterator MBB = Fn.begin(), MBBe = Fn.end(); MBB != MBBe; ++MBB)