-//===-- RegisterCoalescer.h - Register Coalescing Interface ------*- C++ -*-===//
+//===-- RegisterCoalescer.h - Register Coalescing Interface -----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
//
//===----------------------------------------------------------------------===//
//
-// This file contains the abstract interface for register coalescers,
+// This file contains the abstract interface for register coalescers,
// allowing them to interact with and query register allocators.
//
//===----------------------------------------------------------------------===//
/// two registers can be coalesced, CoalescerPair can determine if a copy
/// instruction would become an identity copy after coalescing.
class CoalescerPair {
- const TargetInstrInfo &TII;
const TargetRegisterInfo &TRI;
/// DstReg - The register that will be left after coalescing. It can be a
/// SrcReg - the virtual register that will be coalesced into dstReg.
unsigned SrcReg;
- /// subReg_ - The subregister index of srcReg in DstReg. It is possible the
- /// coalesce SrcReg into a subreg of the larger DstReg when DstReg is a
- /// virtual register.
- unsigned SubIdx;
+ /// DstIdx - The sub-register index of the old DstReg in the new coalesced
+ /// register.
+ unsigned DstIdx;
+
+ /// SrcIdx - The sub-register index of the old SrcReg in the new coalesced
+ /// register.
+ unsigned SrcIdx;
/// Partial - True when the original copy was a partial subregister copy.
bool Partial;
/// CrossClass - True when both regs are virtual, and newRC is constrained.
bool CrossClass;
- /// Flipped - True when DstReg and SrcReg are reversed from the oriignal
+ /// Flipped - True when DstReg and SrcReg are reversed from the original
/// copy instruction.
bool Flipped;
/// NewRC - The register class of the coalesced register, or NULL if DstReg
- /// is a physreg.
+ /// is a physreg. This register class may be a super-register of both
+ /// SrcReg and DstReg.
const TargetRegisterClass *NewRC;
public:
- CoalescerPair(const TargetInstrInfo &tii, const TargetRegisterInfo &tri)
- : TII(tii), TRI(tri), DstReg(0), SrcReg(0), SubIdx(0),
+ CoalescerPair(const TargetRegisterInfo &tri)
+ : TRI(tri), DstReg(0), SrcReg(0), DstIdx(0), SrcIdx(0),
+ Partial(false), CrossClass(false), Flipped(false), NewRC(0) {}
+
+ /// Create a CoalescerPair representing a virtreg-to-physreg copy.
+ /// No need to call setRegisters().
+ CoalescerPair(unsigned VirtReg, unsigned PhysReg,
+ const TargetRegisterInfo &tri)
+ : TRI(tri), DstReg(PhysReg), SrcReg(VirtReg), DstIdx(0), SrcIdx(0),
Partial(false), CrossClass(false), Flipped(false), NewRC(0) {}
/// setRegisters - set registers to match the copy instruction MI. Return
/// getSrcReg - Return the virtual register that will be coalesced away.
unsigned getSrcReg() const { return SrcReg; }
- /// getSubIdx - Return the subregister index in DstReg that SrcReg will be
- /// coalesced into, or 0.
- unsigned getSubIdx() const { return SubIdx; }
+ /// getDstIdx - Return the subregister index that DstReg will be coalesced
+ /// into, or 0.
+ unsigned getDstIdx() const { return DstIdx; }
+
+ /// getSrcIdx - Return the subregister index that SrcReg will be coalesced
+ /// into, or 0.
+ unsigned getSrcIdx() const { return SrcIdx; }
/// getNewRC - Return the register class of the coalesced register.
const TargetRegisterClass *getNewRC() const { return NewRC; }