diff options
Diffstat (limited to 'contrib/llvm/lib/CodeGen/MachineBasicBlock.cpp')
-rw-r--r-- | contrib/llvm/lib/CodeGen/MachineBasicBlock.cpp | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/contrib/llvm/lib/CodeGen/MachineBasicBlock.cpp b/contrib/llvm/lib/CodeGen/MachineBasicBlock.cpp index 78e9950..91810bd 100644 --- a/contrib/llvm/lib/CodeGen/MachineBasicBlock.cpp +++ b/contrib/llvm/lib/CodeGen/MachineBasicBlock.cpp @@ -19,6 +19,7 @@ #include "llvm/CodeGen/LiveVariables.h" #include "llvm/CodeGen/MachineDominators.h" #include "llvm/CodeGen/MachineFunction.h" +#include "llvm/CodeGen/MachineInstrBuilder.h" #include "llvm/CodeGen/MachineLoopInfo.h" #include "llvm/CodeGen/MachineRegisterInfo.h" #include "llvm/CodeGen/SlotIndexes.h" @@ -341,6 +342,38 @@ bool MachineBasicBlock::isLiveIn(unsigned Reg) const { return I != livein_end(); } +unsigned +MachineBasicBlock::addLiveIn(unsigned PhysReg, const TargetRegisterClass *RC) { + assert(getParent() && "MBB must be inserted in function"); + assert(TargetRegisterInfo::isPhysicalRegister(PhysReg) && "Expected physreg"); + assert(RC && "Register class is required"); + assert((isLandingPad() || this == &getParent()->front()) && + "Only the entry block and landing pads can have physreg live ins"); + + bool LiveIn = isLiveIn(PhysReg); + iterator I = SkipPHIsAndLabels(begin()), E = end(); + MachineRegisterInfo &MRI = getParent()->getRegInfo(); + const TargetInstrInfo &TII = *getParent()->getTarget().getInstrInfo(); + + // Look for an existing copy. + if (LiveIn) + for (;I != E && I->isCopy(); ++I) + if (I->getOperand(1).getReg() == PhysReg) { + unsigned VirtReg = I->getOperand(0).getReg(); + if (!MRI.constrainRegClass(VirtReg, RC)) + llvm_unreachable("Incompatible live-in register class."); + return VirtReg; + } + + // No luck, create a virtual register. + unsigned VirtReg = MRI.createVirtualRegister(RC); + BuildMI(*this, I, DebugLoc(), TII.get(TargetOpcode::COPY), VirtReg) + .addReg(PhysReg, RegState::Kill); + if (!LiveIn) + addLiveIn(PhysReg); + return VirtReg; +} + void MachineBasicBlock::moveBefore(MachineBasicBlock *NewAfter) { getParent()->splice(NewAfter, this); } |