1 //===-------------- PPCVSXCopy.cpp - VSX Copy Legalization ----------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // A pass which deals with the complexity of generating legal VSX register
11 // copies to/from register classes which partially overlap with the VSX
12 // register file.
13 //
14 //===----------------------------------------------------------------------===//
15
16 #include "PPC.h"
17 #include "MCTargetDesc/PPCPredicates.h"
18 #include "PPCHazardRecognizers.h"
19 #include "PPCInstrBuilder.h"
20 #include "PPCInstrInfo.h"
21 #include "PPCMachineFunctionInfo.h"
22 #include "PPCTargetMachine.h"
23 #include "llvm/ADT/STLExtras.h"
24 #include "llvm/ADT/Statistic.h"
25 #include "llvm/CodeGen/MachineFrameInfo.h"
26 #include "llvm/CodeGen/MachineFunctionPass.h"
27 #include "llvm/CodeGen/MachineInstrBuilder.h"
28 #include "llvm/CodeGen/MachineMemOperand.h"
29 #include "llvm/CodeGen/MachineRegisterInfo.h"
30 #include "llvm/MC/MCAsmInfo.h"
31 #include "llvm/Support/Debug.h"
32 #include "llvm/Support/ErrorHandling.h"
33 #include "llvm/Support/TargetRegistry.h"
34 #include "llvm/Support/raw_ostream.h"
35
36 using namespace llvm;
37
38 #define DEBUG_TYPE "ppc-vsx-copy"
39
40 namespace llvm {
41 void initializePPCVSXCopyPass(PassRegistry&);
42 }
43
44 namespace {
45 // PPCVSXCopy pass - For copies between VSX registers and non-VSX registers
46 // (Altivec and scalar floating-point registers), we need to transform the
47 // copies into subregister copies with other restrictions.
48 struct PPCVSXCopy : public MachineFunctionPass {
49 static char ID;
PPCVSXCopy__anon6654d73d0111::PPCVSXCopy50 PPCVSXCopy() : MachineFunctionPass(ID) {
51 initializePPCVSXCopyPass(*PassRegistry::getPassRegistry());
52 }
53
54 const TargetInstrInfo *TII;
55
IsRegInClass__anon6654d73d0111::PPCVSXCopy56 bool IsRegInClass(unsigned Reg, const TargetRegisterClass *RC,
57 MachineRegisterInfo &MRI) {
58 if (TargetRegisterInfo::isVirtualRegister(Reg)) {
59 return RC->hasSubClassEq(MRI.getRegClass(Reg));
60 } else if (RC->contains(Reg)) {
61 return true;
62 }
63
64 return false;
65 }
66
IsVSReg__anon6654d73d0111::PPCVSXCopy67 bool IsVSReg(unsigned Reg, MachineRegisterInfo &MRI) {
68 return IsRegInClass(Reg, &PPC::VSRCRegClass, MRI);
69 }
70
IsVRReg__anon6654d73d0111::PPCVSXCopy71 bool IsVRReg(unsigned Reg, MachineRegisterInfo &MRI) {
72 return IsRegInClass(Reg, &PPC::VRRCRegClass, MRI);
73 }
74
IsF8Reg__anon6654d73d0111::PPCVSXCopy75 bool IsF8Reg(unsigned Reg, MachineRegisterInfo &MRI) {
76 return IsRegInClass(Reg, &PPC::F8RCRegClass, MRI);
77 }
78
IsVSFReg__anon6654d73d0111::PPCVSXCopy79 bool IsVSFReg(unsigned Reg, MachineRegisterInfo &MRI) {
80 return IsRegInClass(Reg, &PPC::VSFRCRegClass, MRI);
81 }
82
IsVSSReg__anon6654d73d0111::PPCVSXCopy83 bool IsVSSReg(unsigned Reg, MachineRegisterInfo &MRI) {
84 return IsRegInClass(Reg, &PPC::VSSRCRegClass, MRI);
85 }
86
87 protected:
processBlock__anon6654d73d0111::PPCVSXCopy88 bool processBlock(MachineBasicBlock &MBB) {
89 bool Changed = false;
90
91 MachineRegisterInfo &MRI = MBB.getParent()->getRegInfo();
92 for (MachineBasicBlock::iterator I = MBB.begin(), IE = MBB.end();
93 I != IE; ++I) {
94 MachineInstr *MI = I;
95 if (!MI->isFullCopy())
96 continue;
97
98 MachineOperand &DstMO = MI->getOperand(0);
99 MachineOperand &SrcMO = MI->getOperand(1);
100
101 if ( IsVSReg(DstMO.getReg(), MRI) &&
102 !IsVSReg(SrcMO.getReg(), MRI)) {
103 // This is a copy *to* a VSX register from a non-VSX register.
104 Changed = true;
105
106 const TargetRegisterClass *SrcRC =
107 IsVRReg(SrcMO.getReg(), MRI) ? &PPC::VSHRCRegClass :
108 &PPC::VSLRCRegClass;
109 assert((IsF8Reg(SrcMO.getReg(), MRI) ||
110 IsVRReg(SrcMO.getReg(), MRI) ||
111 IsVSSReg(SrcMO.getReg(), MRI) ||
112 IsVSFReg(SrcMO.getReg(), MRI)) &&
113 "Unknown source for a VSX copy");
114
115 unsigned NewVReg = MRI.createVirtualRegister(SrcRC);
116 BuildMI(MBB, MI, MI->getDebugLoc(),
117 TII->get(TargetOpcode::SUBREG_TO_REG), NewVReg)
118 .addImm(1) // add 1, not 0, because there is no implicit clearing
119 // of the high bits.
120 .addOperand(SrcMO)
121 .addImm(IsVRReg(SrcMO.getReg(), MRI) ? PPC::sub_128 :
122 PPC::sub_64);
123
124 // The source of the original copy is now the new virtual register.
125 SrcMO.setReg(NewVReg);
126 } else if (!IsVSReg(DstMO.getReg(), MRI) &&
127 IsVSReg(SrcMO.getReg(), MRI)) {
128 // This is a copy *from* a VSX register to a non-VSX register.
129 Changed = true;
130
131 const TargetRegisterClass *DstRC =
132 IsVRReg(DstMO.getReg(), MRI) ? &PPC::VSHRCRegClass :
133 &PPC::VSLRCRegClass;
134 assert((IsF8Reg(DstMO.getReg(), MRI) ||
135 IsVSFReg(DstMO.getReg(), MRI) ||
136 IsVSSReg(DstMO.getReg(), MRI) ||
137 IsVRReg(DstMO.getReg(), MRI)) &&
138 "Unknown destination for a VSX copy");
139
140 // Copy the VSX value into a new VSX register of the correct subclass.
141 unsigned NewVReg = MRI.createVirtualRegister(DstRC);
142 BuildMI(MBB, MI, MI->getDebugLoc(),
143 TII->get(TargetOpcode::COPY), NewVReg)
144 .addOperand(SrcMO);
145
146 // Transform the original copy into a subregister extraction copy.
147 SrcMO.setReg(NewVReg);
148 SrcMO.setSubReg(IsVRReg(DstMO.getReg(), MRI) ? PPC::sub_128 :
149 PPC::sub_64);
150 }
151 }
152
153 return Changed;
154 }
155
156 public:
runOnMachineFunction__anon6654d73d0111::PPCVSXCopy157 bool runOnMachineFunction(MachineFunction &MF) override {
158 // If we don't have VSX on the subtarget, don't do anything.
159 const PPCSubtarget &STI = MF.getSubtarget<PPCSubtarget>();
160 if (!STI.hasVSX())
161 return false;
162 TII = STI.getInstrInfo();
163
164 bool Changed = false;
165
166 for (MachineFunction::iterator I = MF.begin(); I != MF.end();) {
167 MachineBasicBlock &B = *I++;
168 if (processBlock(B))
169 Changed = true;
170 }
171
172 return Changed;
173 }
174
getAnalysisUsage__anon6654d73d0111::PPCVSXCopy175 void getAnalysisUsage(AnalysisUsage &AU) const override {
176 MachineFunctionPass::getAnalysisUsage(AU);
177 }
178 };
179 }
180
181 INITIALIZE_PASS(PPCVSXCopy, DEBUG_TYPE,
182 "PowerPC VSX Copy Legalization", false, false)
183
184 char PPCVSXCopy::ID = 0;
185 FunctionPass*
createPPCVSXCopyPass()186 llvm::createPPCVSXCopyPass() { return new PPCVSXCopy(); }
187
188