1 //===-- PPCBranchSelector.cpp - Emit long conditional branches ------------===//
8 //===----------------------------------------------------------------------===//
11 // conditional branches need more than 16 bits of displacement to reach their
16 //===----------------------------------------------------------------------===//
29 #define DEBUG_TYPE "ppc-branch-select"
31 STATISTIC(NumExpanded, "Number of branches expanded to long format");
44     /// BlockSizes - The sizes of the basic blocks in the function.
61 INITIALIZE_PASS(PPCBSel, "ppc-branch-select", "PowerPC Branch Selector",
64 /// createPPCBranchSelectionPass - returns an instance of the Branch Selection
74   // Give the blocks of the function a dense, in-order, numbering.  in runOnMachineFunction()
79     [TII](MachineBasicBlock &MBB, unsigned Offset) -> unsigned {  in runOnMachineFunction()
85     unsigned ParentAlign = MBB.getParent()->getAlignment();  in runOnMachineFunction()
103     if (MBB->getNumber() > 0) {  in runOnMachineFunction()
105       BlockSizes[MBB->getNumber()-1] += AlignExtra;  in runOnMachineFunction()
111       BlockSize += TII->GetInstSizeInBytes(MI);  in runOnMachineFunction()
113     BlockSizes[MBB->getNumber()] = BlockSize;  in runOnMachineFunction()
118   // we know we don't need to shrink any branches in this function.  This is a  in runOnMachineFunction()
137     // Iteratively expand branches until we reach a fixed point.  in runOnMachineFunction()
147         if (I->getOpcode() == PPC::BCC && !I->getOperand(2).isImm())  in runOnMachineFunction()
148           Dest = I->getOperand(2).getMBB();  in runOnMachineFunction()
149         else if ((I->getOpcode() == PPC::BC || I->getOpcode() == PPC::BCn) &&  in runOnMachineFunction()
150                  !I->getOperand(1).isImm())  in runOnMachineFunction()
151           Dest = I->getOperand(1).getMBB();  in runOnMachineFunction()
152         else if ((I->getOpcode() == PPC::BDNZ8 || I->getOpcode() == PPC::BDNZ ||  in runOnMachineFunction()
153                   I->getOpcode() == PPC::BDZ8  || I->getOpcode() == PPC::BDZ) &&  in runOnMachineFunction()
154                  !I->getOperand(0).isImm())  in runOnMachineFunction()
155           Dest = I->getOperand(0).getMBB();  in runOnMachineFunction()
158           MBBStartOffset += TII->GetInstSizeInBytes(*I);  in runOnMachineFunction()
165         if (Dest->getNumber() <= MBB.getNumber()) {  in runOnMachineFunction()
171           for (unsigned i = Dest->getNumber(), e = MBB.getNumber(); i != e; ++i)  in runOnMachineFunction()
176           BranchSize = -MBBStartOffset;  in runOnMachineFunction()
178           for (unsigned i = MBB.getNumber(), e = Dest->getNumber(); i != e; ++i)  in runOnMachineFunction()
182         // If this branch is in range, ignore it.  in runOnMachineFunction()
190         DebugLoc dl = OldBranch->getDebugLoc();  in runOnMachineFunction()
192         if (I->getOpcode() == PPC::BCC) {  in runOnMachineFunction()
197           PPC::Predicate Pred = (PPC::Predicate)I->getOperand(0).getImm();  in runOnMachineFunction()
198           unsigned CRReg = I->getOperand(1).getReg();  in runOnMachineFunction()
201           BuildMI(MBB, I, dl, TII->get(PPC::BCC))  in runOnMachineFunction()
203         } else if (I->getOpcode() == PPC::BC) {  in runOnMachineFunction()
204           unsigned CRBit = I->getOperand(0).getReg();  in runOnMachineFunction()
205           BuildMI(MBB, I, dl, TII->get(PPC::BCn)).addReg(CRBit).addImm(2);  in runOnMachineFunction()
206         } else if (I->getOpcode() == PPC::BCn) {  in runOnMachineFunction()
207           unsigned CRBit = I->getOperand(0).getReg();  in runOnMachineFunction()
208           BuildMI(MBB, I, dl, TII->get(PPC::BC)).addReg(CRBit).addImm(2);  in runOnMachineFunction()
209         } else if (I->getOpcode() == PPC::BDNZ) {  in runOnMachineFunction()
210           BuildMI(MBB, I, dl, TII->get(PPC::BDZ)).addImm(2);  in runOnMachineFunction()
211         } else if (I->getOpcode() == PPC::BDNZ8) {  in runOnMachineFunction()
212           BuildMI(MBB, I, dl, TII->get(PPC::BDZ8)).addImm(2);  in runOnMachineFunction()
213         } else if (I->getOpcode() == PPC::BDZ) {  in runOnMachineFunction()
214           BuildMI(MBB, I, dl, TII->get(PPC::BDNZ)).addImm(2);  in runOnMachineFunction()
215         } else if (I->getOpcode() == PPC::BDZ8) {  in runOnMachineFunction()
216           BuildMI(MBB, I, dl, TII->get(PPC::BDNZ8)).addImm(2);  in runOnMachineFunction()
222         I = BuildMI(MBB, I, dl, TII->get(PPC::B)).addMBB(Dest);  in runOnMachineFunction()
225         OldBranch->eraseFromParent();  in runOnMachineFunction()
227         // Remember that this instruction is 8-bytes, increase the size of the  in runOnMachineFunction()