- //===--------------------------------------------------------------------===//
- // Physical Register Use Info
- //===--------------------------------------------------------------------===//
-
- /// isPhysRegUsed - Return true if the specified register is used in this
- /// function. Also check for clobbered aliases and registers clobbered by
- /// function calls with register mask operands.
- ///
- /// This only works after register allocation. It is primarily used by
- /// PrologEpilogInserter to determine which callee-saved registers need
- /// spilling.
- bool isPhysRegUsed(unsigned Reg) const {
- if (UsedPhysRegMask.test(Reg))
- return true;
- for (MCRegUnitIterator Units(Reg, getTargetRegisterInfo());
- Units.isValid(); ++Units)
- if (UsedRegUnits.test(*Units))
- return true;
- return false;
- }
-
- /// Mark the specified register unit as used in this function.
- /// This should only be called during and after register allocation.
- void setRegUnitUsed(unsigned RegUnit) {
- UsedRegUnits.set(RegUnit);
- }
-
- /// setPhysRegUsed - Mark the specified register used in this function.
- /// This should only be called during and after register allocation.
- void setPhysRegUsed(unsigned Reg) {
- for (MCRegUnitIterator Units(Reg, getTargetRegisterInfo());
- Units.isValid(); ++Units)
- UsedRegUnits.set(*Units);
- }
+ /// Return true if the specified register is modified in this function.
+ /// This checks that no defining machine operands exist for the register or
+ /// any of its aliases. Definitions found on functions marked noreturn are
+ /// ignored.
+ bool isPhysRegModified(unsigned PhysReg) const;