diff --git a/lib/CodeGen/RegAllocSimple.cpp b/lib/CodeGen/RegAllocSimple.cpp index 61109ad1eab..0c363dcd168 100644 --- a/lib/CodeGen/RegAllocSimple.cpp +++ b/lib/CodeGen/RegAllocSimple.cpp @@ -212,6 +212,7 @@ RegAllocSimple::saveVirtRegToStack (MachineBasicBlock &MBB, /// EliminatePHINodes - Eliminate phi nodes by inserting copy instructions in /// predecessor basic blocks. +/// void RegAllocSimple::EliminatePHINodes(MachineBasicBlock &MBB) { const MachineInstrInfo &MII = TM.getInstrInfo(); @@ -220,26 +221,12 @@ void RegAllocSimple::EliminatePHINodes(MachineBasicBlock &MBB) { // Unlink the PHI node from the basic block... but don't delete the PHI yet MBB.erase(MBB.begin()); - DEBUG(std::cerr << "num invalid regs: " << RegsUsed.size() << "\n"); DEBUG(std::cerr << "num ops: " << MI->getNumOperands() << "\n"); assert(MI->getOperand(0).isVirtualRegister() && "PHI node doesn't write virt reg?"); - // a preliminary pass that will invalidate any registers that - // are used by the instruction (including implicit uses) - invalidatePhysRegs(MI); - - // Allocate a physical reg to hold this temporary. - // unsigned virtualReg = MI->getOperand(0).getAllocatedRegNum(); - unsigned physReg = getFreeReg(virtualReg); - // Find the register class of the target register: should be the - // same as the values we're trying to store there - const TargetRegisterClass* regClass = MF->getRegClass(virtualReg); - assert(regClass && "Target register class not found!"); - unsigned dataSize = regClass->getDataSize(); - for (int i = MI->getNumOperands() - 1; i >= 2; i-=2) { MachineOperand &opVal = MI->getOperand(i-1); @@ -274,27 +261,20 @@ void RegAllocSimple::EliminatePHINodes(MachineBasicBlock &MBB) { // are inserted right in front of it and not in front of a non-branch if (!MII.isBranch(opMI->getOpcode())) ++opI; - + + unsigned dataSize = MF->getRegClass(virtualReg)->getDataSize(); + // Retrieve the constant value from this op, move it to target // register of the phi if (opVal.isImmediate()) { - opI = RegInfo->moveImm2Reg(opBlock, opI, physReg, + opI = RegInfo->moveImm2Reg(opBlock, opI, virtualReg, (unsigned) opVal.getImmedValue(), dataSize); } else { - // Allocate a physical register and add a move in the BB - unsigned opVirtualReg = opVal.getAllocatedRegNum(); - unsigned opPhysReg; - opI = moveUseToReg(opBlock, opI, opVirtualReg, physReg); - + opI = RegInfo->moveReg2Reg(opBlock, opI, virtualReg, + opVal.getAllocatedRegNum(), dataSize); } - - // Save that register value to the stack of the TARGET REG - saveVirtRegToStack(opBlock, opI, virtualReg, physReg); } - - // make regs available to other instructions - clearAllRegs(); } // really delete the PHI instruction now! @@ -304,9 +284,6 @@ void RegAllocSimple::EliminatePHINodes(MachineBasicBlock &MBB) { void RegAllocSimple::AllocateBasicBlock(MachineBasicBlock &MBB) { - // Handle PHI instructions specially: add moves to each pred block - EliminatePHINodes(MBB); - // loop over each instruction for (MachineBasicBlock::iterator I = MBB.begin(); I != MBB.end(); ++I) { // Made to combat the incorrect allocation of r2 = add r1, r1 @@ -366,6 +343,12 @@ bool RegAllocSimple::runOnMachineFunction(MachineFunction &Fn) { DEBUG(std::cerr << "Machine Function " << "\n"); MF = &Fn; + // 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)