1 //===------ LeonPasses.cpp - Define passes specific to LEON ---------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
11 //===----------------------------------------------------------------------===//
13 #include "LeonPasses.h"
14 #include "llvm/CodeGen/ISDOpcodes.h"
15 #include "llvm/CodeGen/MachineFunction.h"
16 #include "llvm/CodeGen/MachineInstr.h"
17 #include "llvm/CodeGen/MachineInstrBuilder.h"
18 #include "llvm/CodeGen/MachineRegisterInfo.h"
19 #include "llvm/IR/DiagnosticInfo.h"
20 #include "llvm/IR/LLVMContext.h"
21 #include "llvm/Support/raw_ostream.h"
24 LEONMachineFunctionPass::LEONMachineFunctionPass(char &ID)
25 : MachineFunctionPass(ID) {}
27 //*****************************************************************************
28 //**** InsertNOPLoad pass
29 //*****************************************************************************
30 // This pass fixes the incorrectly working Load instructions that exists for
31 // some earlier versions of the LEON processor line. NOP instructions must
32 // be inserted after the load instruction to ensure that the Load instruction
33 // behaves as expected for these processors.
35 // This pass inserts a NOP after any LD or LDF instruction.
37 char InsertNOPLoad::ID = 0;
39 InsertNOPLoad::InsertNOPLoad() : LEONMachineFunctionPass(ID) {}
41 bool InsertNOPLoad::runOnMachineFunction(MachineFunction &MF) {
42 Subtarget = &MF.getSubtarget<SparcSubtarget>();
43 const TargetInstrInfo &TII = *Subtarget->getInstrInfo();
44 DebugLoc DL = DebugLoc();
46 bool Modified = false;
47 for (auto MFI = MF.begin(), E = MF.end(); MFI != E; ++MFI) {
48 MachineBasicBlock &MBB = *MFI;
49 for (auto MBBI = MBB.begin(), E = MBB.end(); MBBI != E; ++MBBI) {
50 MachineInstr &MI = *MBBI;
51 unsigned Opcode = MI.getOpcode();
52 if (Opcode >= SP::LDDArr && Opcode <= SP::LDrr) {
53 MachineBasicBlock::iterator NMBBI = std::next(MBBI);
54 BuildMI(MBB, NMBBI, DL, TII.get(SP::NOP));
65 //*****************************************************************************
66 //**** DetectRoundChange pass
67 //*****************************************************************************
68 // To prevent any explicit change of the default rounding mode, this pass
69 // detects any call of the fesetround function.
70 // A warning is generated to ensure the user knows this has happened.
72 // Detects an erratum in UT699 LEON 3 processor
74 char DetectRoundChange::ID = 0;
76 DetectRoundChange::DetectRoundChange() : LEONMachineFunctionPass(ID) {}
78 bool DetectRoundChange::runOnMachineFunction(MachineFunction &MF) {
79 Subtarget = &MF.getSubtarget<SparcSubtarget>();
81 bool Modified = false;
82 for (auto MFI = MF.begin(), E = MF.end(); MFI != E; ++MFI) {
83 MachineBasicBlock &MBB = *MFI;
84 for (auto MBBI = MBB.begin(), E = MBB.end(); MBBI != E; ++MBBI) {
85 MachineInstr &MI = *MBBI;
86 unsigned Opcode = MI.getOpcode();
87 if (Opcode == SP::CALL && MI.getNumOperands() > 0) {
88 MachineOperand &MO = MI.getOperand(0);
91 StringRef FuncName = MO.getGlobal()->getName();
92 if (FuncName.compare_lower("fesetround") == 0) {
93 errs() << "Error: You are using the detectroundchange "
94 "option to detect rounding changes that will "
95 "cause LEON errata. The only way to fix this "
96 "is to remove the call to fesetround from "
107 //*****************************************************************************
108 //**** FixAllFDIVSQRT pass
109 //*****************************************************************************
110 // This pass fixes the incorrectly working FDIVx and FSQRTx instructions that
111 // exist for some earlier versions of the LEON processor line. Five NOP
112 // instructions need to be inserted after these instructions to ensure the
113 // correct result is placed in the destination registers before they are used.
115 // This pass implements two fixes:
116 // 1) fixing the FSQRTS and FSQRTD instructions.
117 // 2) fixing the FDIVS and FDIVD instructions.
119 // FSQRTS and FDIVS are converted to FDIVD and FSQRTD respectively earlier in
120 // the pipeline when this option is enabled, so this pass needs only to deal
121 // with the changes that still need implementing for the "double" versions
122 // of these instructions.
124 char FixAllFDIVSQRT::ID = 0;
126 FixAllFDIVSQRT::FixAllFDIVSQRT() : LEONMachineFunctionPass(ID) {}
128 bool FixAllFDIVSQRT::runOnMachineFunction(MachineFunction &MF) {
129 Subtarget = &MF.getSubtarget<SparcSubtarget>();
130 const TargetInstrInfo &TII = *Subtarget->getInstrInfo();
131 DebugLoc DL = DebugLoc();
133 bool Modified = false;
134 for (auto MFI = MF.begin(), E = MF.end(); MFI != E; ++MFI) {
135 MachineBasicBlock &MBB = *MFI;
136 for (auto MBBI = MBB.begin(), E = MBB.end(); MBBI != E; ++MBBI) {
137 MachineInstr &MI = *MBBI;
138 unsigned Opcode = MI.getOpcode();
140 // Note: FDIVS and FSQRTS cannot be generated when this erratum fix is
141 // switched on so we don't need to check for them here. They will
142 // already have been converted to FSQRTD or FDIVD earlier in the
144 if (Opcode == SP::FSQRTD || Opcode == SP::FDIVD) {
145 for (int InsertedCount = 0; InsertedCount < 5; InsertedCount++)
146 BuildMI(MBB, MBBI, DL, TII.get(SP::NOP));
148 MachineBasicBlock::iterator NMBBI = std::next(MBBI);
149 for (int InsertedCount = 0; InsertedCount < 28; InsertedCount++)
150 BuildMI(MBB, NMBBI, DL, TII.get(SP::NOP));