1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
|
//===-- RegisterCoalescer.h - Register Coalescing Interface -----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the abstract interface for register coalescers,
// allowing them to interact with and query register allocators.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_CODEGEN_REGISTERCOALESCER_H
#define LLVM_LIB_CODEGEN_REGISTERCOALESCER_H
namespace llvm {
class MachineInstr;
class TargetRegisterInfo;
class TargetRegisterClass;
class TargetInstrInfo;
/// A helper class for register coalescers. When deciding if
/// two registers can be coalesced, CoalescerPair can determine if a copy
/// instruction would become an identity copy after coalescing.
class CoalescerPair {
const TargetRegisterInfo &TRI;
/// The register that will be left after coalescing. It can be a
/// virtual or physical register.
unsigned DstReg;
/// The virtual register that will be coalesced into dstReg.
unsigned SrcReg;
/// The sub-register index of the old DstReg in the new coalesced register.
unsigned DstIdx;
/// The sub-register index of the old SrcReg in the new coalesced register.
unsigned SrcIdx;
/// True when the original copy was a partial subregister copy.
bool Partial;
/// True when both regs are virtual and newRC is constrained.
bool CrossClass;
/// True when DstReg and SrcReg are reversed from the original
/// copy instruction.
bool Flipped;
/// The register class of the coalesced register, or NULL if DstReg
/// is a physreg. This register class may be a super-register of both
/// SrcReg and DstReg.
const TargetRegisterClass *NewRC;
public:
CoalescerPair(const TargetRegisterInfo &tri)
: TRI(tri), DstReg(0), SrcReg(0), DstIdx(0), SrcIdx(0),
Partial(false), CrossClass(false), Flipped(false), NewRC(nullptr) {}
/// 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(nullptr) {}
/// Set registers to match the copy instruction MI. Return
/// false if MI is not a coalescable copy instruction.
bool setRegisters(const MachineInstr*);
/// Swap SrcReg and DstReg. Return false if swapping is impossible
/// because DstReg is a physical register, or SubIdx is set.
bool flip();
/// Return true if MI is a copy instruction that will become
/// an identity copy after coalescing.
bool isCoalescable(const MachineInstr*) const;
/// Return true if DstReg is a physical register.
bool isPhys() const { return !NewRC; }
/// Return true if the original copy instruction did not copy
/// the full register, but was a subreg operation.
bool isPartial() const { return Partial; }
/// Return true if DstReg is virtual and NewRC is a smaller
/// register class than DstReg's.
bool isCrossClass() const { return CrossClass; }
/// Return true when getSrcReg is the register being defined by
/// the original copy instruction.
bool isFlipped() const { return Flipped; }
/// Return the register (virtual or physical) that will remain
/// after coalescing.
unsigned getDstReg() const { return DstReg; }
/// Return the virtual register that will be coalesced away.
unsigned getSrcReg() const { return SrcReg; }
/// Return the subregister index that DstReg will be coalesced into, or 0.
unsigned getDstIdx() const { return DstIdx; }
/// Return the subregister index that SrcReg will be coalesced into, or 0.
unsigned getSrcIdx() const { return SrcIdx; }
/// Return the register class of the coalesced register.
const TargetRegisterClass *getNewRC() const { return NewRC; }
};
} // End llvm namespace
#endif
|
