LLVM  6.0.0svn
ExpandISelPseudos.cpp
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1 //===-- llvm/CodeGen/ExpandISelPseudos.cpp ----------------------*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // Expand Pseudo-instructions produced by ISel. These are usually to allow
11 // the expansion to contain control flow, such as a conditional move
12 // implemented with a conditional branch and a phi, or an atomic operation
13 // implemented with a loop.
14 //
15 //===----------------------------------------------------------------------===//
16 
19 #include "llvm/CodeGen/Passes.h"
22 #include "llvm/Support/Debug.h"
23 using namespace llvm;
24 
25 #define DEBUG_TYPE "expand-isel-pseudos"
26 
27 namespace {
28  class ExpandISelPseudos : public MachineFunctionPass {
29  public:
30  static char ID; // Pass identification, replacement for typeid
31  ExpandISelPseudos() : MachineFunctionPass(ID) {}
32 
33  private:
34  bool runOnMachineFunction(MachineFunction &MF) override;
35 
36  void getAnalysisUsage(AnalysisUsage &AU) const override {
38  }
39  };
40 } // end anonymous namespace
41 
42 char ExpandISelPseudos::ID = 0;
44 INITIALIZE_PASS(ExpandISelPseudos, DEBUG_TYPE,
45  "Expand ISel Pseudo-instructions", false, false)
46 
47 bool ExpandISelPseudos::runOnMachineFunction(MachineFunction &MF) {
48  bool Changed = false;
49  const TargetLowering *TLI = MF.getSubtarget().getTargetLowering();
50 
51  // Iterate through each instruction in the function, looking for pseudos.
52  for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) {
53  MachineBasicBlock *MBB = &*I;
54  for (MachineBasicBlock::iterator MBBI = MBB->begin(), MBBE = MBB->end();
55  MBBI != MBBE; ) {
56  MachineInstr &MI = *MBBI++;
57 
58  // If MI is a pseudo, expand it.
59  if (MI.usesCustomInsertionHook()) {
60  Changed = true;
61  MachineBasicBlock *NewMBB = TLI->EmitInstrWithCustomInserter(MI, MBB);
62  // The expansion may involve new basic blocks.
63  if (NewMBB != MBB) {
64  MBB = NewMBB;
65  I = NewMBB->getIterator();
66  MBBI = NewMBB->begin();
67  MBBE = NewMBB->end();
68  }
69  }
70  }
71  }
72 
73  return Changed;
74 }
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
MachineFunctionPass - This class adapts the FunctionPass interface to allow convenient creation of pa...
This class defines information used to lower LLVM code to legal SelectionDAG operators that the targe...
char & ExpandISelPseudosID
ExpandISelPseudos - This pass expands pseudo-instructions.
void getAnalysisUsage(AnalysisUsage &AU) const override
getAnalysisUsage - Subclasses that override getAnalysisUsage must call this.
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
#define DEBUG_TYPE
Represent the analysis usage information of a pass.
self_iterator getIterator()
Definition: ilist_node.h:82
virtual MachineBasicBlock * EmitInstrWithCustomInserter(MachineInstr &MI, MachineBasicBlock *MBB) const
This method should be implemented by targets that mark instructions with the &#39;usesCustomInserter&#39; fla...
Iterator for intrusive lists based on ilist_node.
Representation of each machine instruction.
Definition: MachineInstr.h:59
#define I(x, y, z)
Definition: MD5.cpp:58
bool usesCustomInsertionHook(QueryType Type=IgnoreBundle) const
Return true if this instruction requires custom insertion support when the DAG scheduler is inserting...
Definition: MachineInstr.h:697
INITIALIZE_PASS(ExpandISelPseudos, DEBUG_TYPE, "Expand ISel Pseudo-instructions", false, false) bool ExpandISelPseudos
IRTranslator LLVM IR MI
This file describes how to lower LLVM code to machine code.