+ setRegClass(Reg, NewRC);
+ return true;
+}
+
+/// createVirtualRegister - Create and return a new virtual register in the
+/// function with the specified register class.
+///
+unsigned
+MachineRegisterInfo::createVirtualRegister(const TargetRegisterClass *RegClass){
+ assert(RegClass && "Cannot create register without RegClass!");
+ assert(RegClass->isAllocatable() &&
+ "Virtual register RegClass must be allocatable.");
+
+ // New virtual register number.
+ unsigned Reg = TargetRegisterInfo::index2VirtReg(getNumVirtRegs());
+ VRegInfo.grow(Reg);
+ VRegInfo[Reg].first = RegClass;
+ RegAllocHints.grow(Reg);
+ return Reg;
+}
+
+/// clearVirtRegs - Remove all virtual registers (after physreg assignment).
+void MachineRegisterInfo::clearVirtRegs() {
+#ifndef NDEBUG
+ for (unsigned i = 0, e = getNumVirtRegs(); i != e; ++i)
+ assert(VRegInfo[TargetRegisterInfo::index2VirtReg(i)].second == 0 &&
+ "Vreg use list non-empty still?");
+#endif
+ VRegInfo.clear();
+}
+
+/// Add MO to the linked list of operands for its register.
+void MachineRegisterInfo::addRegOperandToUseList(MachineOperand *MO) {
+ assert(!MO->isOnRegUseList() && "Already on list");
+ MachineOperand *&HeadRef = getRegUseDefListHead(MO->getReg());
+ MachineOperand *const Head = HeadRef;
+
+ // Head points to the first list element.
+ // Next is NULL on the last list element.
+ // Prev pointers are circular, so Head->Prev == Last.
+
+ // Head is NULL for an empty list.
+ if (!Head) {
+ MO->Contents.Reg.Prev = MO;
+ MO->Contents.Reg.Next = 0;
+ HeadRef = MO;
+ return;
+ }
+ assert(MO->getReg() == Head->getReg() && "Different regs on the same list!");
+
+ // Insert MO between Last and Head in the circular Prev chain.
+ MachineOperand *Last = Head->Contents.Reg.Prev;
+ assert(Last && "Inconsistent use list");
+ assert(MO->getReg() == Last->getReg() && "Different regs on the same list!");
+ Head->Contents.Reg.Prev = MO;
+ MO->Contents.Reg.Prev = Last;
+
+ // Def operands always precede uses. This allows def_iterator to stop early.
+ // Insert def operands at the front, and use operands at the back.
+ if (MO->isDef()) {
+ // Insert def at the front.
+ MO->Contents.Reg.Next = Head;
+ HeadRef = MO;
+ } else {
+ // Insert use at the end.
+ MO->Contents.Reg.Next = 0;
+ Last->Contents.Reg.Next = MO;
+ }
+}
+
+/// Remove MO from its use-def list.
+void MachineRegisterInfo::removeRegOperandFromUseList(MachineOperand *MO) {
+ assert(MO->isOnRegUseList() && "Operand not on use list");
+ MachineOperand *&HeadRef = getRegUseDefListHead(MO->getReg());
+ MachineOperand *const Head = HeadRef;
+ assert(Head && "List already empty");
+
+ // Unlink this from the doubly linked list of operands.
+ MachineOperand *Next = MO->Contents.Reg.Next;
+ MachineOperand *Prev = MO->Contents.Reg.Prev;
+
+ // Prev links are circular, next link is NULL instead of looping back to Head.
+ if (MO == Head)
+ HeadRef = Next;
+ else
+ Prev->Contents.Reg.Next = Next;
+
+ (Next ? Next : Head)->Contents.Reg.Prev = Prev;
+
+ MO->Contents.Reg.Prev = 0;
+ MO->Contents.Reg.Next = 0;