aboutsummaryrefslogtreecommitdiffstats
path: root/lib/Target/SystemZ/SystemZTargetMachine.cpp
blob: 73198b1af0a50e2ed8cb657da98a5227addd8d54 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
//===-- SystemZTargetMachine.cpp - Define TargetMachine for SystemZ -------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "SystemZTargetMachine.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"

using namespace llvm;

extern "C" void LLVMInitializeSystemZTarget() {
  // Register the target.
  RegisterTargetMachine<SystemZTargetMachine> X(TheSystemZTarget);
}

SystemZTargetMachine::SystemZTargetMachine(const Target &T, StringRef TT,
                                           StringRef CPU, StringRef FS,
                                           const TargetOptions &Options,
                                           Reloc::Model RM, CodeModel::Model CM,
                                           CodeGenOpt::Level OL)
    : LLVMTargetMachine(T, TT, CPU, FS, Options, RM, CM, OL),
      TLOF(make_unique<TargetLoweringObjectFileELF>()),
      // Make sure that global data has at least 16 bits of alignment by
      // default, so that we can refer to it using LARL.  We don't have any
      // special requirements for stack variables though.
      DL("E-m:e-i1:8:16-i8:8:16-i64:64-f128:64-a:8:16-n32:64"),
      Subtarget(TT, CPU, FS, *this) {
  initAsmInfo();
}

SystemZTargetMachine::~SystemZTargetMachine() {}

namespace {
/// SystemZ Code Generator Pass Configuration Options.
class SystemZPassConfig : public TargetPassConfig {
public:
  SystemZPassConfig(SystemZTargetMachine *TM, PassManagerBase &PM)
    : TargetPassConfig(TM, PM) {}

  SystemZTargetMachine &getSystemZTargetMachine() const {
    return getTM<SystemZTargetMachine>();
  }

  void addIRPasses() override;
  bool addInstSelector() override;
  void addPreSched2() override;
  void addPreEmitPass() override;
};
} // end anonymous namespace

void SystemZPassConfig::addIRPasses() {
  TargetPassConfig::addIRPasses();
}

bool SystemZPassConfig::addInstSelector() {
  addPass(createSystemZISelDag(getSystemZTargetMachine(), getOptLevel()));

 if (getOptLevel() != CodeGenOpt::None)
    addPass(createSystemZLDCleanupPass(getSystemZTargetMachine()));

  return false;
}

void SystemZPassConfig::addPreSched2() {
  if (getOptLevel() != CodeGenOpt::None &&
      getSystemZTargetMachine().getSubtargetImpl()->hasLoadStoreOnCond())
    addPass(&IfConverterID);
}

void SystemZPassConfig::addPreEmitPass() {
  // We eliminate comparisons here rather than earlier because some
  // transformations can change the set of available CC values and we
  // generally want those transformations to have priority.  This is
  // especially true in the commonest case where the result of the comparison
  // is used by a single in-range branch instruction, since we will then
  // be able to fuse the compare and the branch instead.
  //
  // For example, two-address NILF can sometimes be converted into
  // three-address RISBLG.  NILF produces a CC value that indicates whether
  // the low word is zero, but RISBLG does not modify CC at all.  On the
  // other hand, 64-bit ANDs like NILL can sometimes be converted to RISBG.
  // The CC value produced by NILL isn't useful for our purposes, but the
  // value produced by RISBG can be used for any comparison with zero
  // (not just equality).  So there are some transformations that lose
  // CC values (while still being worthwhile) and others that happen to make
  // the CC result more useful than it was originally.
  //
  // Another reason is that we only want to use BRANCH ON COUNT in cases
  // where we know that the count register is not going to be spilled.
  //
  // Doing it so late makes it more likely that a register will be reused
  // between the comparison and the branch, but it isn't clear whether
  // preventing that would be a win or not.
  if (getOptLevel() != CodeGenOpt::None)
    addPass(createSystemZElimComparePass(getSystemZTargetMachine()), false);
  if (getOptLevel() != CodeGenOpt::None)
    addPass(createSystemZShortenInstPass(getSystemZTargetMachine()), false);
  addPass(createSystemZLongBranchPass(getSystemZTargetMachine()));
}

TargetPassConfig *SystemZTargetMachine::createPassConfig(PassManagerBase &PM) {
  return new SystemZPassConfig(this, PM);
}