1 //===-- llvm/CodeGen/ExpandISelPseudos.cpp ----------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
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.
15 //===----------------------------------------------------------------------===//
17 #define DEBUG_TYPE "expand-isel-pseudos"
18 #include "llvm/CodeGen/MachineFunction.h"
19 #include "llvm/CodeGen/MachineFunctionPass.h"
20 #include "llvm/CodeGen/Passes.h"
21 #include "llvm/Target/TargetLowering.h"
22 #include "llvm/Target/TargetMachine.h"
23 #include "llvm/Support/Debug.h"
27 class ExpandISelPseudos : public MachineFunctionPass {
29 static char ID; // Pass identification, replacement for typeid
30 ExpandISelPseudos() : MachineFunctionPass(ID) {}
33 virtual bool runOnMachineFunction(MachineFunction &MF);
35 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
36 MachineFunctionPass::getAnalysisUsage(AU);
39 } // end anonymous namespace
41 char ExpandISelPseudos::ID = 0;
42 char &llvm::ExpandISelPseudosID = ExpandISelPseudos::ID;
43 INITIALIZE_PASS(ExpandISelPseudos, "expand-isel-pseudos",
44 "Expand ISel Pseudo-instructions", false, false)
46 bool ExpandISelPseudos::runOnMachineFunction(MachineFunction &MF) {
48 const TargetLowering *TLI = MF.getTarget().getTargetLowering();
50 // Iterate through each instruction in the function, looking for pseudos.
51 for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) {
52 MachineBasicBlock *MBB = I;
53 for (MachineBasicBlock::iterator MBBI = MBB->begin(), MBBE = MBB->end();
55 MachineInstr *MI = MBBI++;
57 // If MI is a pseudo, expand it.
58 if (MI->usesCustomInsertionHook()) {
60 MachineBasicBlock *NewMBB =
61 TLI->EmitInstrWithCustomInserter(MI, MBB);
62 // The expansion may involve new basic blocks.
66 MBBI = NewMBB->begin();