1//===- AArch64PostCoalescerPass.cpp - AArch64 Post Coalescer pass ---------===//
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#include "AArch64InstrInfo.h"
11#include "AArch64MachineFunctionInfo.h"
12#include "llvm/CodeGen/LiveIntervals.h"
13#include "llvm/CodeGen/MachineRegisterInfo.h"
14#include "llvm/InitializePasses.h"
15
16using namespace llvm;
17
18#define DEBUG_TYPE "aarch64-post-coalescer-pass"
19
20namespace {
21
22struct AArch64PostCoalescer : public MachineFunctionPass {
23 static char ID;
24
25 AArch64PostCoalescer() : MachineFunctionPass(ID) {
26 initializeAArch64PostCoalescerPass(*PassRegistry::getPassRegistry());
27 }
28
29 LiveIntervals *LIS;
30 MachineRegisterInfo *MRI;
31
32 bool runOnMachineFunction(MachineFunction &MF) override;
33
34 StringRef getPassName() const override {
35 return "AArch64 Post Coalescer pass";
36 }
37
38 void getAnalysisUsage(AnalysisUsage &AU) const override {
39 AU.setPreservesAll();
40 AU.addRequired<LiveIntervalsWrapperPass>();
41 MachineFunctionPass::getAnalysisUsage(AU);
42 }
43};
44
45char AArch64PostCoalescer::ID = 0;
46
47} // end anonymous namespace
48
49INITIALIZE_PASS_BEGIN(AArch64PostCoalescer, "aarch64-post-coalescer-pass",
50 "AArch64 Post Coalescer Pass", false, false)
51INITIALIZE_PASS_DEPENDENCY(LiveIntervalsWrapperPass)
52INITIALIZE_PASS_END(AArch64PostCoalescer, "aarch64-post-coalescer-pass",
53 "AArch64 Post Coalescer Pass", false, false)
54
55bool AArch64PostCoalescer::runOnMachineFunction(MachineFunction &MF) {
56 if (skipFunction(F: MF.getFunction()))
57 return false;
58
59 AArch64FunctionInfo *FuncInfo = MF.getInfo<AArch64FunctionInfo>();
60 if (!FuncInfo->hasStreamingModeChanges())
61 return false;
62
63 MRI = &MF.getRegInfo();
64 LIS = &getAnalysis<LiveIntervalsWrapperPass>().getLIS();
65 bool Changed = false;
66
67 for (MachineBasicBlock &MBB : MF) {
68 for (MachineInstr &MI : make_early_inc_range(Range&: MBB)) {
69 switch (MI.getOpcode()) {
70 default:
71 break;
72 case AArch64::COALESCER_BARRIER_FPR16:
73 case AArch64::COALESCER_BARRIER_FPR32:
74 case AArch64::COALESCER_BARRIER_FPR64:
75 case AArch64::COALESCER_BARRIER_FPR128: {
76 Register Src = MI.getOperand(i: 1).getReg();
77 Register Dst = MI.getOperand(i: 0).getReg();
78 if (Src != Dst)
79 MRI->replaceRegWith(FromReg: Dst, ToReg: Src);
80
81 // MI must be erased from the basic block before recalculating the live
82 // interval.
83 LIS->RemoveMachineInstrFromMaps(MI);
84 MI.eraseFromParent();
85
86 LIS->removeInterval(Reg: Src);
87 LIS->createAndComputeVirtRegInterval(Reg: Src);
88
89 Changed = true;
90 break;
91 }
92 }
93 }
94 }
95
96 return Changed;
97}
98
99FunctionPass *llvm::createAArch64PostCoalescerPass() {
100 return new AArch64PostCoalescer();
101}
102