1 //===- llvm/CodeGen/GlobalISel/GIMatchTableExecutor.cpp -------------------===//
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 /// \file
10 /// This file implements the GIMatchTableExecutor class.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/CodeGen/GlobalISel/GIMatchTableExecutor.h"
15 #include "llvm/CodeGen/GlobalISel/Utils.h"
16 #include "llvm/CodeGen/MachineInstr.h"
17 #include "llvm/CodeGen/MachineOperand.h"
18 #include "llvm/CodeGen/MachineRegisterInfo.h"
19 
20 #define DEBUG_TYPE "gi-match-table-executor"
21 
22 using namespace llvm;
23 
24 GIMatchTableExecutor::MatcherState::MatcherState(unsigned MaxRenderers)
25     : Renderers(MaxRenderers) {}
26 
27 GIMatchTableExecutor::GIMatchTableExecutor() = default;
28 
29 bool GIMatchTableExecutor::isOperandImmEqual(const MachineOperand &MO,
30                                              int64_t Value,
31                                              const MachineRegisterInfo &MRI,
32                                              bool Splat) const {
33   if (MO.isReg() && MO.getReg()) {
34     if (auto VRegVal = getIConstantVRegValWithLookThrough(MO.getReg(), MRI))
35       return VRegVal->Value.getSExtValue() == Value;
36 
37     if (Splat) {
38       if (auto VRegVal = getIConstantSplatVal(MO.getReg(), MRI))
39         return VRegVal->getSExtValue() == Value;
40     }
41   }
42   return false;
43 }
44 
45 bool GIMatchTableExecutor::isBaseWithConstantOffset(
46     const MachineOperand &Root, const MachineRegisterInfo &MRI) const {
47   if (!Root.isReg())
48     return false;
49 
50   MachineInstr *RootI = MRI.getVRegDef(Root.getReg());
51   if (RootI->getOpcode() != TargetOpcode::G_PTR_ADD)
52     return false;
53 
54   MachineOperand &RHS = RootI->getOperand(2);
55   MachineInstr *RHSI = MRI.getVRegDef(RHS.getReg());
56   if (RHSI->getOpcode() != TargetOpcode::G_CONSTANT)
57     return false;
58 
59   return true;
60 }
61 
62 bool GIMatchTableExecutor::isObviouslySafeToFold(MachineInstr &MI,
63                                                  MachineInstr &IntoMI) const {
64   // Immediate neighbours are already folded.
65   if (MI.getParent() == IntoMI.getParent() &&
66       std::next(MI.getIterator()) == IntoMI.getIterator())
67     return true;
68 
69   // Convergent instructions cannot be moved in the CFG.
70   if (MI.isConvergent() && MI.getParent() != IntoMI.getParent())
71     return false;
72 
73   return !MI.mayLoadOrStore() && !MI.mayRaiseFPException() &&
74          !MI.hasUnmodeledSideEffects() && MI.implicit_operands().empty();
75 }
76