LLVM 20.0.0git
LeonPasses.cpp
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1//===------ LeonPasses.cpp - Define passes specific to LEON ---------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9//
10//===----------------------------------------------------------------------===//
11
12#include "LeonPasses.h"
13#include "SparcSubtarget.h"
19
20using namespace llvm;
21
24
25//*****************************************************************************
26//**** InsertNOPLoad pass
27//*****************************************************************************
28// This pass fixes the incorrectly working Load instructions that exists for
29// some earlier versions of the LEON processor line. NOP instructions must
30// be inserted after the load instruction to ensure that the Load instruction
31// behaves as expected for these processors.
32//
33// This pass inserts a NOP after any LD or LDF instruction.
34//
35char InsertNOPLoad::ID = 0;
36
38
41 if (!Subtarget->insertNOPLoad())
42 return false;
43
46
47 bool Modified = false;
48 for (MachineBasicBlock &MBB : MF) {
49 for (auto MBBI = MBB.begin(), E = MBB.end(); MBBI != E; ++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));
55 Modified = true;
56 }
57 }
58 }
59
60 return Modified;
61}
62
63
64
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.
71//
72// Detects an erratum in UT699 LEON 3 processor
73
75
77
80 if (!Subtarget->detectRoundChange())
81 return false;
82
83 bool Modified = false;
84 for (MachineBasicBlock &MBB : MF) {
85 for (MachineInstr &MI : MBB) {
86 unsigned Opcode = MI.getOpcode();
87 if (Opcode == SP::CALL && MI.getNumOperands() > 0) {
88 MachineOperand &MO = MI.getOperand(0);
89
90 if (MO.isGlobal()) {
91 StringRef FuncName = MO.getGlobal()->getName();
92 if (FuncName.compare_insensitive("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 "
97 "the source code.\n";
98 }
99 }
100 }
101 }
102 }
103
104 return Modified;
105}
106
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.
114//
115// This pass implements two fixes:
116// 1) fixing the FSQRTS and FSQRTD instructions.
117// 2) fixing the FDIVS and FDIVD instructions.
118//
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.
123//
124char FixAllFDIVSQRT::ID = 0;
125
127
130 if (!Subtarget->fixAllFDIVSQRT())
131 return false;
132
134 DebugLoc DL = DebugLoc();
135
136 bool Modified = false;
137 for (MachineBasicBlock &MBB : MF) {
138 for (auto MBBI = MBB.begin(), E = MBB.end(); MBBI != E; ++MBBI) {
139 MachineInstr &MI = *MBBI;
140 unsigned Opcode = MI.getOpcode();
141
142 // Note: FDIVS and FSQRTS cannot be generated when this erratum fix is
143 // switched on so we don't need to check for them here. They will
144 // already have been converted to FSQRTD or FDIVD earlier in the
145 // pipeline.
146 if (Opcode == SP::FSQRTD || Opcode == SP::FDIVD) {
147 for (int InsertedCount = 0; InsertedCount < 5; InsertedCount++)
148 BuildMI(MBB, MBBI, DL, TII.get(SP::NOP));
149
150 MachineBasicBlock::iterator NMBBI = std::next(MBBI);
151 for (int InsertedCount = 0; InsertedCount < 28; InsertedCount++)
152 BuildMI(MBB, NMBBI, DL, TII.get(SP::NOP));
153
154 Modified = true;
155 }
156 }
157 }
158
159 return Modified;
160}
MachineBasicBlock & MBB
MachineBasicBlock MachineBasicBlock::iterator DebugLoc DL
MachineBasicBlock MachineBasicBlock::iterator MBBI
const HexagonInstrInfo * TII
IRTranslator LLVM IR MI
A debug info location.
Definition: DebugLoc.h:33
bool runOnMachineFunction(MachineFunction &MF) override
runOnMachineFunction - This method must be overloaded to perform the desired machine code transformat...
Definition: LeonPasses.cpp:78
bool runOnMachineFunction(MachineFunction &MF) override
runOnMachineFunction - This method must be overloaded to perform the desired machine code transformat...
Definition: LeonPasses.cpp:128
static char ID
Definition: LeonPasses.h:70
bool runOnMachineFunction(MachineFunction &MF) override
runOnMachineFunction - This method must be overloaded to perform the desired machine code transformat...
Definition: LeonPasses.cpp:39
static char ID
Definition: LeonPasses.h:42
const SparcSubtarget * Subtarget
Definition: LeonPasses.h:23
MachineFunctionPass - This class adapts the FunctionPass interface to allow convenient creation of pa...
const TargetSubtargetInfo & getSubtarget() const
getSubtarget - Return the subtarget for which this machine code is being compiled.
Representation of each machine instruction.
Definition: MachineInstr.h:69
MachineOperand class - Representation of each machine instruction operand.
const GlobalValue * getGlobal() const
bool isGlobal() const
isGlobal - Tests if this is a MO_GlobalAddress operand.
const SparcInstrInfo * getInstrInfo() const override
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:50
int compare_insensitive(StringRef RHS) const
Compare two strings, ignoring case.
Definition: StringRef.cpp:37
TargetInstrInfo - Interface to description of machine instruction set.
StringRef getName() const
Return a constant reference to the value's name.
Definition: Value.cpp:309
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
MachineInstrBuilder BuildMI(MachineFunction &MF, const MIMetadata &MIMD, const MCInstrDesc &MCID)
Builder interface. Specify how to create the initial instruction itself.
raw_fd_ostream & errs()
This returns a reference to a raw_ostream for standard error.