mirror of
https://github.com/c64scene-ar/llvm-6502.git
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95762124a1
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@20965 91177308-0d34-0410-b5e6-96231b3b80d8
1094 lines
40 KiB
C++
1094 lines
40 KiB
C++
//===-- SelectionDAGISel.cpp - Implement the SelectionDAGISel class -------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the LLVM research group and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This implements the SelectionDAGISel class.
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "isel"
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#include "llvm/CodeGen/SelectionDAGISel.h"
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#include "llvm/Constants.h"
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#include "llvm/DerivedTypes.h"
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#include "llvm/Function.h"
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#include "llvm/Instructions.h"
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#include "llvm/Intrinsics.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/CodeGen/MachineFrameInfo.h"
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#include "llvm/CodeGen/MachineInstrBuilder.h"
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#include "llvm/CodeGen/SelectionDAG.h"
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#include "llvm/CodeGen/SSARegMap.h"
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#include "llvm/Target/TargetData.h"
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#include "llvm/Target/TargetFrameInfo.h"
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#include "llvm/Target/TargetInstrInfo.h"
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#include "llvm/Target/TargetLowering.h"
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#include "llvm/Target/TargetMachine.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/Debug.h"
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#include <map>
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#include <iostream>
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using namespace llvm;
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#ifndef _NDEBUG
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static cl::opt<bool>
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ViewDAGs("view-isel-dags", cl::Hidden,
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cl::desc("Pop up a window to show isel dags as they are selected"));
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#else
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static const bool ViewDAGS = 0;
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#endif
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namespace llvm {
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//===--------------------------------------------------------------------===//
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/// FunctionLoweringInfo - This contains information that is global to a
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/// function that is used when lowering a region of the function.
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class FunctionLoweringInfo {
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public:
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TargetLowering &TLI;
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Function &Fn;
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MachineFunction &MF;
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SSARegMap *RegMap;
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FunctionLoweringInfo(TargetLowering &TLI, Function &Fn,MachineFunction &MF);
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/// MBBMap - A mapping from LLVM basic blocks to their machine code entry.
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std::map<const BasicBlock*, MachineBasicBlock *> MBBMap;
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/// ValueMap - Since we emit code for the function a basic block at a time,
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/// we must remember which virtual registers hold the values for
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/// cross-basic-block values.
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std::map<const Value*, unsigned> ValueMap;
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/// StaticAllocaMap - Keep track of frame indices for fixed sized allocas in
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/// the entry block. This allows the allocas to be efficiently referenced
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/// anywhere in the function.
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std::map<const AllocaInst*, int> StaticAllocaMap;
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/// BlockLocalArguments - If any arguments are only used in a single basic
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/// block, and if the target can access the arguments without side-effects,
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/// avoid emitting CopyToReg nodes for those arguments. This map keeps
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/// track of which arguments are local to each BB.
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std::multimap<BasicBlock*, std::pair<Argument*,
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unsigned> > BlockLocalArguments;
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unsigned MakeReg(MVT::ValueType VT) {
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return RegMap->createVirtualRegister(TLI.getRegClassFor(VT));
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}
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unsigned CreateRegForValue(const Value *V) {
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MVT::ValueType VT = TLI.getValueType(V->getType());
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// The common case is that we will only create one register for this
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// value. If we have that case, create and return the virtual register.
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unsigned NV = TLI.getNumElements(VT);
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if (NV == 1) {
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// If we are promoting this value, pick the next largest supported type.
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return MakeReg(TLI.getTypeToTransformTo(VT));
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}
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// If this value is represented with multiple target registers, make sure
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// to create enough consequtive registers of the right (smaller) type.
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unsigned NT = VT-1; // Find the type to use.
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while (TLI.getNumElements((MVT::ValueType)NT) != 1)
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--NT;
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unsigned R = MakeReg((MVT::ValueType)NT);
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for (unsigned i = 1; i != NV; ++i)
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MakeReg((MVT::ValueType)NT);
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return R;
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}
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unsigned InitializeRegForValue(const Value *V) {
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unsigned &R = ValueMap[V];
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assert(R == 0 && "Already initialized this value register!");
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return R = CreateRegForValue(V);
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}
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};
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}
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/// isUsedOutsideOfDefiningBlock - Return true if this instruction is used by
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/// PHI nodes or outside of the basic block that defines it.
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static bool isUsedOutsideOfDefiningBlock(Instruction *I) {
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if (isa<PHINode>(I)) return true;
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BasicBlock *BB = I->getParent();
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for (Value::use_iterator UI = I->use_begin(), E = I->use_end(); UI != E; ++UI)
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if (cast<Instruction>(*UI)->getParent() != BB || isa<PHINode>(*UI))
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return true;
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return false;
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}
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FunctionLoweringInfo::FunctionLoweringInfo(TargetLowering &tli,
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Function &fn, MachineFunction &mf)
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: TLI(tli), Fn(fn), MF(mf), RegMap(MF.getSSARegMap()) {
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// Initialize the mapping of values to registers. This is only set up for
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// instruction values that are used outside of the block that defines
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// them.
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for (Function::arg_iterator AI = Fn.arg_begin(), E = Fn.arg_end(); AI != E; ++AI)
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InitializeRegForValue(AI);
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Function::iterator BB = Fn.begin(), E = Fn.end();
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for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
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if (AllocaInst *AI = dyn_cast<AllocaInst>(I))
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if (ConstantUInt *CUI = dyn_cast<ConstantUInt>(AI->getArraySize())) {
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const Type *Ty = AI->getAllocatedType();
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uint64_t TySize = TLI.getTargetData().getTypeSize(Ty);
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unsigned Align = TLI.getTargetData().getTypeAlignment(Ty);
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TySize *= CUI->getValue(); // Get total allocated size.
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StaticAllocaMap[AI] =
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MF.getFrameInfo()->CreateStackObject((unsigned)TySize, Align);
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}
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for (; BB != E; ++BB)
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for (BasicBlock::iterator I = BB->begin(), e = BB->end(); I != e; ++I)
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if (!I->use_empty() && isUsedOutsideOfDefiningBlock(I))
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if (!isa<AllocaInst>(I) ||
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!StaticAllocaMap.count(cast<AllocaInst>(I)))
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InitializeRegForValue(I);
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// Create an initial MachineBasicBlock for each LLVM BasicBlock in F. This
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// also creates the initial PHI MachineInstrs, though none of the input
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// operands are populated.
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for (Function::iterator BB = Fn.begin(), E = Fn.end(); BB != E; ++BB) {
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MachineBasicBlock *MBB = new MachineBasicBlock(BB);
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MBBMap[BB] = MBB;
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MF.getBasicBlockList().push_back(MBB);
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// Create Machine PHI nodes for LLVM PHI nodes, lowering them as
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// appropriate.
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PHINode *PN;
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for (BasicBlock::iterator I = BB->begin();
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(PN = dyn_cast<PHINode>(I)); ++I)
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if (!PN->use_empty()) {
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unsigned NumElements =
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TLI.getNumElements(TLI.getValueType(PN->getType()));
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unsigned PHIReg = ValueMap[PN];
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assert(PHIReg &&"PHI node does not have an assigned virtual register!");
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for (unsigned i = 0; i != NumElements; ++i)
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BuildMI(MBB, TargetInstrInfo::PHI, PN->getNumOperands(), PHIReg+i);
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}
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}
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}
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//===----------------------------------------------------------------------===//
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/// SelectionDAGLowering - This is the common target-independent lowering
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/// implementation that is parameterized by a TargetLowering object.
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/// Also, targets can overload any lowering method.
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///
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namespace llvm {
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class SelectionDAGLowering {
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MachineBasicBlock *CurMBB;
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std::map<const Value*, SDOperand> NodeMap;
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/// PendingLoads - Loads are not emitted to the program immediately. We bunch
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/// them up and then emit token factor nodes when possible. This allows us to
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/// get simple disambiguation between loads without worrying about alias
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/// analysis.
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std::vector<SDOperand> PendingLoads;
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public:
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// TLI - This is information that describes the available target features we
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// need for lowering. This indicates when operations are unavailable,
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// implemented with a libcall, etc.
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TargetLowering &TLI;
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SelectionDAG &DAG;
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const TargetData &TD;
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/// FuncInfo - Information about the function as a whole.
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///
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FunctionLoweringInfo &FuncInfo;
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SelectionDAGLowering(SelectionDAG &dag, TargetLowering &tli,
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FunctionLoweringInfo &funcinfo)
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: TLI(tli), DAG(dag), TD(DAG.getTarget().getTargetData()),
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FuncInfo(funcinfo) {
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}
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/// getRoot - Return the current virtual root of the Selection DAG.
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///
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SDOperand getRoot() {
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if (PendingLoads.empty())
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return DAG.getRoot();
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if (PendingLoads.size() == 1) {
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SDOperand Root = PendingLoads[0];
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DAG.setRoot(Root);
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PendingLoads.clear();
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return Root;
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}
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// Otherwise, we have to make a token factor node.
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SDOperand Root = DAG.getNode(ISD::TokenFactor, MVT::Other, PendingLoads);
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PendingLoads.clear();
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DAG.setRoot(Root);
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return Root;
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}
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void visit(Instruction &I) { visit(I.getOpcode(), I); }
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void visit(unsigned Opcode, User &I) {
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switch (Opcode) {
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default: assert(0 && "Unknown instruction type encountered!");
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abort();
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// Build the switch statement using the Instruction.def file.
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#define HANDLE_INST(NUM, OPCODE, CLASS) \
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case Instruction::OPCODE:return visit##OPCODE((CLASS&)I);
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#include "llvm/Instruction.def"
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}
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}
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void setCurrentBasicBlock(MachineBasicBlock *MBB) { CurMBB = MBB; }
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SDOperand getIntPtrConstant(uint64_t Val) {
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return DAG.getConstant(Val, TLI.getPointerTy());
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}
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SDOperand getValue(const Value *V) {
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SDOperand &N = NodeMap[V];
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if (N.Val) return N;
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MVT::ValueType VT = TLI.getValueType(V->getType());
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if (Constant *C = const_cast<Constant*>(dyn_cast<Constant>(V)))
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if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
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visit(CE->getOpcode(), *CE);
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assert(N.Val && "visit didn't populate the ValueMap!");
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return N;
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} else if (GlobalValue *GV = dyn_cast<GlobalValue>(C)) {
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return N = DAG.getGlobalAddress(GV, VT);
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} else if (isa<ConstantPointerNull>(C)) {
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return N = DAG.getConstant(0, TLI.getPointerTy());
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} else if (isa<UndefValue>(C)) {
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/// FIXME: Implement UNDEFVALUE better.
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if (MVT::isInteger(VT))
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return N = DAG.getConstant(0, VT);
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else if (MVT::isFloatingPoint(VT))
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return N = DAG.getConstantFP(0, VT);
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else
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assert(0 && "Unknown value type!");
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} else if (ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
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return N = DAG.getConstantFP(CFP->getValue(), VT);
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} else {
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// Canonicalize all constant ints to be unsigned.
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return N = DAG.getConstant(cast<ConstantIntegral>(C)->getRawValue(),VT);
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}
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if (const AllocaInst *AI = dyn_cast<AllocaInst>(V)) {
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std::map<const AllocaInst*, int>::iterator SI =
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FuncInfo.StaticAllocaMap.find(AI);
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if (SI != FuncInfo.StaticAllocaMap.end())
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return DAG.getFrameIndex(SI->second, TLI.getPointerTy());
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}
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std::map<const Value*, unsigned>::const_iterator VMI =
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FuncInfo.ValueMap.find(V);
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assert(VMI != FuncInfo.ValueMap.end() && "Value not in map!");
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return N = DAG.getCopyFromReg(VMI->second, VT, DAG.getEntryNode());
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}
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const SDOperand &setValue(const Value *V, SDOperand NewN) {
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SDOperand &N = NodeMap[V];
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assert(N.Val == 0 && "Already set a value for this node!");
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return N = NewN;
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}
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// Terminator instructions.
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void visitRet(ReturnInst &I);
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void visitBr(BranchInst &I);
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void visitUnreachable(UnreachableInst &I) { /* noop */ }
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// These all get lowered before this pass.
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void visitSwitch(SwitchInst &I) { assert(0 && "TODO"); }
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void visitInvoke(InvokeInst &I) { assert(0 && "TODO"); }
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void visitUnwind(UnwindInst &I) { assert(0 && "TODO"); }
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//
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void visitBinary(User &I, unsigned Opcode);
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void visitAdd(User &I) { visitBinary(I, ISD::ADD); }
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void visitSub(User &I) { visitBinary(I, ISD::SUB); }
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void visitMul(User &I) { visitBinary(I, ISD::MUL); }
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void visitDiv(User &I) {
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visitBinary(I, I.getType()->isUnsigned() ? ISD::UDIV : ISD::SDIV);
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}
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void visitRem(User &I) {
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visitBinary(I, I.getType()->isUnsigned() ? ISD::UREM : ISD::SREM);
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}
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void visitAnd(User &I) { visitBinary(I, ISD::AND); }
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void visitOr (User &I) { visitBinary(I, ISD::OR); }
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void visitXor(User &I) { visitBinary(I, ISD::XOR); }
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void visitShl(User &I) { visitBinary(I, ISD::SHL); }
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void visitShr(User &I) {
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visitBinary(I, I.getType()->isUnsigned() ? ISD::SRL : ISD::SRA);
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}
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void visitSetCC(User &I, ISD::CondCode SignedOpc, ISD::CondCode UnsignedOpc);
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void visitSetEQ(User &I) { visitSetCC(I, ISD::SETEQ, ISD::SETEQ); }
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void visitSetNE(User &I) { visitSetCC(I, ISD::SETNE, ISD::SETNE); }
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void visitSetLE(User &I) { visitSetCC(I, ISD::SETLE, ISD::SETULE); }
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void visitSetGE(User &I) { visitSetCC(I, ISD::SETGE, ISD::SETUGE); }
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void visitSetLT(User &I) { visitSetCC(I, ISD::SETLT, ISD::SETULT); }
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void visitSetGT(User &I) { visitSetCC(I, ISD::SETGT, ISD::SETUGT); }
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void visitGetElementPtr(User &I);
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void visitCast(User &I);
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void visitSelect(User &I);
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//
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void visitMalloc(MallocInst &I);
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void visitFree(FreeInst &I);
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void visitAlloca(AllocaInst &I);
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void visitLoad(LoadInst &I);
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void visitStore(StoreInst &I);
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void visitPHI(PHINode &I) { } // PHI nodes are handled specially.
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void visitCall(CallInst &I);
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void visitVAStart(CallInst &I);
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void visitVANext(VANextInst &I);
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void visitVAArg(VAArgInst &I);
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void visitVAEnd(CallInst &I);
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void visitVACopy(CallInst &I);
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void visitFrameReturnAddress(CallInst &I, bool isFrameAddress);
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void visitMemIntrinsic(CallInst &I, unsigned Op);
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void visitUserOp1(Instruction &I) {
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assert(0 && "UserOp1 should not exist at instruction selection time!");
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abort();
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}
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void visitUserOp2(Instruction &I) {
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assert(0 && "UserOp2 should not exist at instruction selection time!");
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abort();
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}
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};
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} // end namespace llvm
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void SelectionDAGLowering::visitRet(ReturnInst &I) {
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if (I.getNumOperands() == 0) {
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DAG.setRoot(DAG.getNode(ISD::RET, MVT::Other, getRoot()));
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return;
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}
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SDOperand Op1 = getValue(I.getOperand(0));
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MVT::ValueType TmpVT;
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switch (Op1.getValueType()) {
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default: assert(0 && "Unknown value type!");
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case MVT::i1:
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case MVT::i8:
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case MVT::i16:
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case MVT::i32:
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// If this is a machine where 32-bits is legal or expanded, promote to
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// 32-bits, otherwise, promote to 64-bits.
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if (TLI.getTypeAction(MVT::i32) == TargetLowering::Promote)
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TmpVT = TLI.getTypeToTransformTo(MVT::i32);
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else
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TmpVT = MVT::i32;
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// Extend integer types to result type.
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if (I.getOperand(0)->getType()->isSigned())
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Op1 = DAG.getNode(ISD::SIGN_EXTEND, TmpVT, Op1);
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else
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Op1 = DAG.getNode(ISD::ZERO_EXTEND, TmpVT, Op1);
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break;
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case MVT::f32:
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// Extend float to double.
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Op1 = DAG.getNode(ISD::FP_EXTEND, MVT::f64, Op1);
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break;
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case MVT::i64:
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case MVT::f64:
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break; // No extension needed!
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}
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DAG.setRoot(DAG.getNode(ISD::RET, MVT::Other, getRoot(), Op1));
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}
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void SelectionDAGLowering::visitBr(BranchInst &I) {
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// Update machine-CFG edges.
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MachineBasicBlock *Succ0MBB = FuncInfo.MBBMap[I.getSuccessor(0)];
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// Figure out which block is immediately after the current one.
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MachineBasicBlock *NextBlock = 0;
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MachineFunction::iterator BBI = CurMBB;
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if (++BBI != CurMBB->getParent()->end())
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NextBlock = BBI;
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if (I.isUnconditional()) {
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// If this is not a fall-through branch, emit the branch.
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if (Succ0MBB != NextBlock)
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DAG.setRoot(DAG.getNode(ISD::BR, MVT::Other, getRoot(),
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DAG.getBasicBlock(Succ0MBB)));
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} else {
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MachineBasicBlock *Succ1MBB = FuncInfo.MBBMap[I.getSuccessor(1)];
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SDOperand Cond = getValue(I.getCondition());
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if (Succ1MBB == NextBlock) {
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// If the condition is false, fall through. This means we should branch
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// if the condition is true to Succ #0.
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DAG.setRoot(DAG.getNode(ISD::BRCOND, MVT::Other, getRoot(),
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Cond, DAG.getBasicBlock(Succ0MBB)));
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} else if (Succ0MBB == NextBlock) {
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// If the condition is true, fall through. This means we should branch if
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// the condition is false to Succ #1. Invert the condition first.
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SDOperand True = DAG.getConstant(1, Cond.getValueType());
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Cond = DAG.getNode(ISD::XOR, Cond.getValueType(), Cond, True);
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DAG.setRoot(DAG.getNode(ISD::BRCOND, MVT::Other, getRoot(),
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Cond, DAG.getBasicBlock(Succ1MBB)));
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} else {
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// Neither edge is a fall through. If the comparison is true, jump to
|
|
// Succ#0, otherwise branch unconditionally to succ #1.
|
|
DAG.setRoot(DAG.getNode(ISD::BRCOND, MVT::Other, getRoot(),
|
|
Cond, DAG.getBasicBlock(Succ0MBB)));
|
|
DAG.setRoot(DAG.getNode(ISD::BR, MVT::Other, getRoot(),
|
|
DAG.getBasicBlock(Succ1MBB)));
|
|
}
|
|
}
|
|
}
|
|
|
|
void SelectionDAGLowering::visitBinary(User &I, unsigned Opcode) {
|
|
SDOperand Op1 = getValue(I.getOperand(0));
|
|
SDOperand Op2 = getValue(I.getOperand(1));
|
|
|
|
if (isa<ShiftInst>(I))
|
|
Op2 = DAG.getNode(ISD::ZERO_EXTEND, TLI.getShiftAmountTy(), Op2);
|
|
|
|
setValue(&I, DAG.getNode(Opcode, Op1.getValueType(), Op1, Op2));
|
|
}
|
|
|
|
void SelectionDAGLowering::visitSetCC(User &I,ISD::CondCode SignedOpcode,
|
|
ISD::CondCode UnsignedOpcode) {
|
|
SDOperand Op1 = getValue(I.getOperand(0));
|
|
SDOperand Op2 = getValue(I.getOperand(1));
|
|
ISD::CondCode Opcode = SignedOpcode;
|
|
if (I.getOperand(0)->getType()->isUnsigned())
|
|
Opcode = UnsignedOpcode;
|
|
setValue(&I, DAG.getSetCC(Opcode, MVT::i1, Op1, Op2));
|
|
}
|
|
|
|
void SelectionDAGLowering::visitSelect(User &I) {
|
|
SDOperand Cond = getValue(I.getOperand(0));
|
|
SDOperand TrueVal = getValue(I.getOperand(1));
|
|
SDOperand FalseVal = getValue(I.getOperand(2));
|
|
setValue(&I, DAG.getNode(ISD::SELECT, TrueVal.getValueType(), Cond,
|
|
TrueVal, FalseVal));
|
|
}
|
|
|
|
void SelectionDAGLowering::visitCast(User &I) {
|
|
SDOperand N = getValue(I.getOperand(0));
|
|
MVT::ValueType SrcTy = TLI.getValueType(I.getOperand(0)->getType());
|
|
MVT::ValueType DestTy = TLI.getValueType(I.getType());
|
|
|
|
if (N.getValueType() == DestTy) {
|
|
setValue(&I, N); // noop cast.
|
|
} else if (isInteger(SrcTy)) {
|
|
if (isInteger(DestTy)) { // Int -> Int cast
|
|
if (DestTy < SrcTy) // Truncating cast?
|
|
setValue(&I, DAG.getNode(ISD::TRUNCATE, DestTy, N));
|
|
else if (I.getOperand(0)->getType()->isSigned())
|
|
setValue(&I, DAG.getNode(ISD::SIGN_EXTEND, DestTy, N));
|
|
else
|
|
setValue(&I, DAG.getNode(ISD::ZERO_EXTEND, DestTy, N));
|
|
} else { // Int -> FP cast
|
|
if (I.getOperand(0)->getType()->isSigned())
|
|
setValue(&I, DAG.getNode(ISD::SINT_TO_FP, DestTy, N));
|
|
else
|
|
setValue(&I, DAG.getNode(ISD::UINT_TO_FP, DestTy, N));
|
|
}
|
|
} else {
|
|
assert(isFloatingPoint(SrcTy) && "Unknown value type!");
|
|
if (isFloatingPoint(DestTy)) { // FP -> FP cast
|
|
if (DestTy < SrcTy) // Rounding cast?
|
|
setValue(&I, DAG.getNode(ISD::FP_ROUND, DestTy, N));
|
|
else
|
|
setValue(&I, DAG.getNode(ISD::FP_EXTEND, DestTy, N));
|
|
} else { // FP -> Int cast.
|
|
if (I.getType()->isSigned())
|
|
setValue(&I, DAG.getNode(ISD::FP_TO_SINT, DestTy, N));
|
|
else
|
|
setValue(&I, DAG.getNode(ISD::FP_TO_UINT, DestTy, N));
|
|
}
|
|
}
|
|
}
|
|
|
|
void SelectionDAGLowering::visitGetElementPtr(User &I) {
|
|
SDOperand N = getValue(I.getOperand(0));
|
|
const Type *Ty = I.getOperand(0)->getType();
|
|
const Type *UIntPtrTy = TD.getIntPtrType();
|
|
|
|
for (GetElementPtrInst::op_iterator OI = I.op_begin()+1, E = I.op_end();
|
|
OI != E; ++OI) {
|
|
Value *Idx = *OI;
|
|
if (const StructType *StTy = dyn_cast<StructType> (Ty)) {
|
|
unsigned Field = cast<ConstantUInt>(Idx)->getValue();
|
|
if (Field) {
|
|
// N = N + Offset
|
|
uint64_t Offset = TD.getStructLayout(StTy)->MemberOffsets[Field];
|
|
N = DAG.getNode(ISD::ADD, N.getValueType(), N,
|
|
getIntPtrConstant(Offset));
|
|
}
|
|
Ty = StTy->getElementType(Field);
|
|
} else {
|
|
Ty = cast<SequentialType>(Ty)->getElementType();
|
|
if (!isa<Constant>(Idx) || !cast<Constant>(Idx)->isNullValue()) {
|
|
// N = N + Idx * ElementSize;
|
|
uint64_t ElementSize = TD.getTypeSize(Ty);
|
|
SDOperand IdxN = getValue(Idx), Scale = getIntPtrConstant(ElementSize);
|
|
|
|
// If the index is smaller or larger than intptr_t, truncate or extend
|
|
// it.
|
|
if (IdxN.getValueType() < Scale.getValueType()) {
|
|
if (Idx->getType()->isSigned())
|
|
IdxN = DAG.getNode(ISD::SIGN_EXTEND, Scale.getValueType(), IdxN);
|
|
else
|
|
IdxN = DAG.getNode(ISD::ZERO_EXTEND, Scale.getValueType(), IdxN);
|
|
} else if (IdxN.getValueType() > Scale.getValueType())
|
|
IdxN = DAG.getNode(ISD::TRUNCATE, Scale.getValueType(), IdxN);
|
|
|
|
IdxN = DAG.getNode(ISD::MUL, N.getValueType(), IdxN, Scale);
|
|
|
|
N = DAG.getNode(ISD::ADD, N.getValueType(), N, IdxN);
|
|
}
|
|
}
|
|
}
|
|
setValue(&I, N);
|
|
}
|
|
|
|
void SelectionDAGLowering::visitAlloca(AllocaInst &I) {
|
|
// If this is a fixed sized alloca in the entry block of the function,
|
|
// allocate it statically on the stack.
|
|
if (FuncInfo.StaticAllocaMap.count(&I))
|
|
return; // getValue will auto-populate this.
|
|
|
|
const Type *Ty = I.getAllocatedType();
|
|
uint64_t TySize = TLI.getTargetData().getTypeSize(Ty);
|
|
unsigned Align = TLI.getTargetData().getTypeAlignment(Ty);
|
|
|
|
SDOperand AllocSize = getValue(I.getArraySize());
|
|
MVT::ValueType IntPtr = TLI.getPointerTy();
|
|
if (IntPtr < AllocSize.getValueType())
|
|
AllocSize = DAG.getNode(ISD::TRUNCATE, IntPtr, AllocSize);
|
|
else if (IntPtr > AllocSize.getValueType())
|
|
AllocSize = DAG.getNode(ISD::ZERO_EXTEND, IntPtr, AllocSize);
|
|
|
|
AllocSize = DAG.getNode(ISD::MUL, IntPtr, AllocSize,
|
|
getIntPtrConstant(TySize));
|
|
|
|
// Handle alignment. If the requested alignment is less than or equal to the
|
|
// stack alignment, ignore it and round the size of the allocation up to the
|
|
// stack alignment size. If the size is greater than the stack alignment, we
|
|
// note this in the DYNAMIC_STACKALLOC node.
|
|
unsigned StackAlign =
|
|
TLI.getTargetMachine().getFrameInfo()->getStackAlignment();
|
|
if (Align <= StackAlign) {
|
|
Align = 0;
|
|
// Add SA-1 to the size.
|
|
AllocSize = DAG.getNode(ISD::ADD, AllocSize.getValueType(), AllocSize,
|
|
getIntPtrConstant(StackAlign-1));
|
|
// Mask out the low bits for alignment purposes.
|
|
AllocSize = DAG.getNode(ISD::AND, AllocSize.getValueType(), AllocSize,
|
|
getIntPtrConstant(~(uint64_t)(StackAlign-1)));
|
|
}
|
|
|
|
SDOperand DSA = DAG.getNode(ISD::DYNAMIC_STACKALLOC, AllocSize.getValueType(),
|
|
getRoot(), AllocSize,
|
|
getIntPtrConstant(Align));
|
|
DAG.setRoot(setValue(&I, DSA).getValue(1));
|
|
|
|
// Inform the Frame Information that we have just allocated a variable-sized
|
|
// object.
|
|
CurMBB->getParent()->getFrameInfo()->CreateVariableSizedObject();
|
|
}
|
|
|
|
|
|
void SelectionDAGLowering::visitLoad(LoadInst &I) {
|
|
SDOperand Ptr = getValue(I.getOperand(0));
|
|
|
|
SDOperand Root;
|
|
if (I.isVolatile())
|
|
Root = getRoot();
|
|
else {
|
|
// Do not serialize non-volatile loads against each other.
|
|
Root = DAG.getRoot();
|
|
}
|
|
|
|
SDOperand L = DAG.getLoad(TLI.getValueType(I.getType()), Root, Ptr);
|
|
setValue(&I, L);
|
|
|
|
if (I.isVolatile())
|
|
DAG.setRoot(L.getValue(1));
|
|
else
|
|
PendingLoads.push_back(L.getValue(1));
|
|
}
|
|
|
|
|
|
void SelectionDAGLowering::visitStore(StoreInst &I) {
|
|
Value *SrcV = I.getOperand(0);
|
|
SDOperand Src = getValue(SrcV);
|
|
SDOperand Ptr = getValue(I.getOperand(1));
|
|
DAG.setRoot(DAG.getNode(ISD::STORE, MVT::Other, getRoot(), Src, Ptr));
|
|
}
|
|
|
|
void SelectionDAGLowering::visitCall(CallInst &I) {
|
|
const char *RenameFn = 0;
|
|
if (Function *F = I.getCalledFunction())
|
|
switch (F->getIntrinsicID()) {
|
|
case 0: break; // Not an intrinsic.
|
|
case Intrinsic::vastart: visitVAStart(I); return;
|
|
case Intrinsic::vaend: visitVAEnd(I); return;
|
|
case Intrinsic::vacopy: visitVACopy(I); return;
|
|
case Intrinsic::returnaddress: visitFrameReturnAddress(I, false); return;
|
|
case Intrinsic::frameaddress: visitFrameReturnAddress(I, true); return;
|
|
default:
|
|
// FIXME: IMPLEMENT THESE.
|
|
// readport, writeport, readio, writeio
|
|
assert(0 && "This intrinsic is not implemented yet!");
|
|
return;
|
|
case Intrinsic::setjmp: RenameFn = "setjmp"; break;
|
|
case Intrinsic::longjmp: RenameFn = "longjmp"; break;
|
|
case Intrinsic::memcpy: visitMemIntrinsic(I, ISD::MEMCPY); return;
|
|
case Intrinsic::memset: visitMemIntrinsic(I, ISD::MEMSET); return;
|
|
case Intrinsic::memmove: visitMemIntrinsic(I, ISD::MEMMOVE); return;
|
|
|
|
case Intrinsic::isunordered:
|
|
setValue(&I, DAG.getSetCC(ISD::SETUO, MVT::i1, getValue(I.getOperand(1)),
|
|
getValue(I.getOperand(2))));
|
|
return;
|
|
case Intrinsic::pcmarker: {
|
|
SDOperand Num = getValue(I.getOperand(1));
|
|
DAG.setRoot(DAG.getNode(ISD::PCMARKER, MVT::Other, getRoot(), Num));
|
|
return;
|
|
}
|
|
|
|
}
|
|
|
|
SDOperand Callee;
|
|
if (!RenameFn)
|
|
Callee = getValue(I.getOperand(0));
|
|
else
|
|
Callee = DAG.getExternalSymbol(RenameFn, TLI.getPointerTy());
|
|
std::vector<std::pair<SDOperand, const Type*> > Args;
|
|
|
|
for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i) {
|
|
Value *Arg = I.getOperand(i);
|
|
SDOperand ArgNode = getValue(Arg);
|
|
Args.push_back(std::make_pair(ArgNode, Arg->getType()));
|
|
}
|
|
|
|
const PointerType *PT = cast<PointerType>(I.getCalledValue()->getType());
|
|
const FunctionType *FTy = cast<FunctionType>(PT->getElementType());
|
|
|
|
std::pair<SDOperand,SDOperand> Result =
|
|
TLI.LowerCallTo(getRoot(), I.getType(), FTy->isVarArg(), Callee, Args, DAG);
|
|
if (I.getType() != Type::VoidTy)
|
|
setValue(&I, Result.first);
|
|
DAG.setRoot(Result.second);
|
|
}
|
|
|
|
void SelectionDAGLowering::visitMalloc(MallocInst &I) {
|
|
SDOperand Src = getValue(I.getOperand(0));
|
|
|
|
MVT::ValueType IntPtr = TLI.getPointerTy();
|
|
|
|
if (IntPtr < Src.getValueType())
|
|
Src = DAG.getNode(ISD::TRUNCATE, IntPtr, Src);
|
|
else if (IntPtr > Src.getValueType())
|
|
Src = DAG.getNode(ISD::ZERO_EXTEND, IntPtr, Src);
|
|
|
|
// Scale the source by the type size.
|
|
uint64_t ElementSize = TD.getTypeSize(I.getType()->getElementType());
|
|
Src = DAG.getNode(ISD::MUL, Src.getValueType(),
|
|
Src, getIntPtrConstant(ElementSize));
|
|
|
|
std::vector<std::pair<SDOperand, const Type*> > Args;
|
|
Args.push_back(std::make_pair(Src, TLI.getTargetData().getIntPtrType()));
|
|
|
|
std::pair<SDOperand,SDOperand> Result =
|
|
TLI.LowerCallTo(getRoot(), I.getType(), false,
|
|
DAG.getExternalSymbol("malloc", IntPtr),
|
|
Args, DAG);
|
|
setValue(&I, Result.first); // Pointers always fit in registers
|
|
DAG.setRoot(Result.second);
|
|
}
|
|
|
|
void SelectionDAGLowering::visitFree(FreeInst &I) {
|
|
std::vector<std::pair<SDOperand, const Type*> > Args;
|
|
Args.push_back(std::make_pair(getValue(I.getOperand(0)),
|
|
TLI.getTargetData().getIntPtrType()));
|
|
MVT::ValueType IntPtr = TLI.getPointerTy();
|
|
std::pair<SDOperand,SDOperand> Result =
|
|
TLI.LowerCallTo(getRoot(), Type::VoidTy, false,
|
|
DAG.getExternalSymbol("free", IntPtr), Args, DAG);
|
|
DAG.setRoot(Result.second);
|
|
}
|
|
|
|
std::pair<SDOperand, SDOperand>
|
|
TargetLowering::LowerVAStart(SDOperand Chain, SelectionDAG &DAG) {
|
|
// We have no sane default behavior, just emit a useful error message and bail
|
|
// out.
|
|
std::cerr << "Variable arguments handling not implemented on this target!\n";
|
|
abort();
|
|
return std::make_pair(SDOperand(), SDOperand());
|
|
}
|
|
|
|
SDOperand TargetLowering::LowerVAEnd(SDOperand Chain, SDOperand L,
|
|
SelectionDAG &DAG) {
|
|
// Default to a noop.
|
|
return Chain;
|
|
}
|
|
|
|
std::pair<SDOperand,SDOperand>
|
|
TargetLowering::LowerVACopy(SDOperand Chain, SDOperand L, SelectionDAG &DAG) {
|
|
// Default to returning the input list.
|
|
return std::make_pair(L, Chain);
|
|
}
|
|
|
|
std::pair<SDOperand,SDOperand>
|
|
TargetLowering::LowerVAArgNext(bool isVANext, SDOperand Chain, SDOperand VAList,
|
|
const Type *ArgTy, SelectionDAG &DAG) {
|
|
// We have no sane default behavior, just emit a useful error message and bail
|
|
// out.
|
|
std::cerr << "Variable arguments handling not implemented on this target!\n";
|
|
abort();
|
|
return std::make_pair(SDOperand(), SDOperand());
|
|
}
|
|
|
|
|
|
void SelectionDAGLowering::visitVAStart(CallInst &I) {
|
|
std::pair<SDOperand,SDOperand> Result = TLI.LowerVAStart(getRoot(), DAG);
|
|
setValue(&I, Result.first);
|
|
DAG.setRoot(Result.second);
|
|
}
|
|
|
|
void SelectionDAGLowering::visitVAArg(VAArgInst &I) {
|
|
std::pair<SDOperand,SDOperand> Result =
|
|
TLI.LowerVAArgNext(false, getRoot(), getValue(I.getOperand(0)),
|
|
I.getType(), DAG);
|
|
setValue(&I, Result.first);
|
|
DAG.setRoot(Result.second);
|
|
}
|
|
|
|
void SelectionDAGLowering::visitVANext(VANextInst &I) {
|
|
std::pair<SDOperand,SDOperand> Result =
|
|
TLI.LowerVAArgNext(true, getRoot(), getValue(I.getOperand(0)),
|
|
I.getArgType(), DAG);
|
|
setValue(&I, Result.first);
|
|
DAG.setRoot(Result.second);
|
|
}
|
|
|
|
void SelectionDAGLowering::visitVAEnd(CallInst &I) {
|
|
DAG.setRoot(TLI.LowerVAEnd(getRoot(), getValue(I.getOperand(1)), DAG));
|
|
}
|
|
|
|
void SelectionDAGLowering::visitVACopy(CallInst &I) {
|
|
std::pair<SDOperand,SDOperand> Result =
|
|
TLI.LowerVACopy(getRoot(), getValue(I.getOperand(1)), DAG);
|
|
setValue(&I, Result.first);
|
|
DAG.setRoot(Result.second);
|
|
}
|
|
|
|
|
|
// It is always conservatively correct for llvm.returnaddress and
|
|
// llvm.frameaddress to return 0.
|
|
std::pair<SDOperand, SDOperand>
|
|
TargetLowering::LowerFrameReturnAddress(bool isFrameAddr, SDOperand Chain,
|
|
unsigned Depth, SelectionDAG &DAG) {
|
|
return std::make_pair(DAG.getConstant(0, getPointerTy()), Chain);
|
|
}
|
|
|
|
SDOperand TargetLowering::LowerOperation(SDOperand Op) {
|
|
assert(0 && "LowerOperation not implemented for this target!");
|
|
abort();
|
|
return SDOperand();
|
|
}
|
|
|
|
void SelectionDAGLowering::visitFrameReturnAddress(CallInst &I, bool isFrame) {
|
|
unsigned Depth = (unsigned)cast<ConstantUInt>(I.getOperand(1))->getValue();
|
|
std::pair<SDOperand,SDOperand> Result =
|
|
TLI.LowerFrameReturnAddress(isFrame, getRoot(), Depth, DAG);
|
|
setValue(&I, Result.first);
|
|
DAG.setRoot(Result.second);
|
|
}
|
|
|
|
void SelectionDAGLowering::visitMemIntrinsic(CallInst &I, unsigned Op) {
|
|
std::vector<SDOperand> Ops;
|
|
Ops.push_back(getRoot());
|
|
Ops.push_back(getValue(I.getOperand(1)));
|
|
Ops.push_back(getValue(I.getOperand(2)));
|
|
Ops.push_back(getValue(I.getOperand(3)));
|
|
Ops.push_back(getValue(I.getOperand(4)));
|
|
DAG.setRoot(DAG.getNode(Op, MVT::Other, Ops));
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// SelectionDAGISel code
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
unsigned SelectionDAGISel::MakeReg(MVT::ValueType VT) {
|
|
return RegMap->createVirtualRegister(TLI.getRegClassFor(VT));
|
|
}
|
|
|
|
|
|
|
|
bool SelectionDAGISel::runOnFunction(Function &Fn) {
|
|
MachineFunction &MF = MachineFunction::construct(&Fn, TLI.getTargetMachine());
|
|
RegMap = MF.getSSARegMap();
|
|
DEBUG(std::cerr << "\n\n\n=== " << Fn.getName() << "\n");
|
|
|
|
FunctionLoweringInfo FuncInfo(TLI, Fn, MF);
|
|
|
|
for (Function::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I)
|
|
SelectBasicBlock(I, MF, FuncInfo);
|
|
|
|
return true;
|
|
}
|
|
|
|
|
|
SDOperand SelectionDAGISel::
|
|
CopyValueToVirtualRegister(SelectionDAGLowering &SDL, Value *V, unsigned Reg) {
|
|
SelectionDAG &DAG = SDL.DAG;
|
|
SDOperand Op = SDL.getValue(V);
|
|
assert((Op.getOpcode() != ISD::CopyFromReg ||
|
|
cast<RegSDNode>(Op)->getReg() != Reg) &&
|
|
"Copy from a reg to the same reg!");
|
|
return DAG.getCopyToReg(SDL.getRoot(), Op, Reg);
|
|
}
|
|
|
|
/// IsOnlyUsedInOneBasicBlock - If the specified argument is only used in a
|
|
/// single basic block, return that block. Otherwise, return a null pointer.
|
|
static BasicBlock *IsOnlyUsedInOneBasicBlock(Argument *A) {
|
|
if (A->use_empty()) return 0;
|
|
BasicBlock *BB = cast<Instruction>(A->use_back())->getParent();
|
|
for (Argument::use_iterator UI = A->use_begin(), E = A->use_end(); UI != E;
|
|
++UI)
|
|
if (isa<PHINode>(*UI) || cast<Instruction>(*UI)->getParent() != BB)
|
|
return 0; // Disagreement among the users?
|
|
|
|
// Okay, there is a single BB user. Only permit this optimization if this is
|
|
// the entry block, otherwise, we might sink argument loads into loops and
|
|
// stuff. Later, when we have global instruction selection, this won't be an
|
|
// issue clearly.
|
|
if (BB == BB->getParent()->begin())
|
|
return BB;
|
|
return 0;
|
|
}
|
|
|
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void SelectionDAGISel::
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LowerArguments(BasicBlock *BB, SelectionDAGLowering &SDL,
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std::vector<SDOperand> &UnorderedChains) {
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// If this is the entry block, emit arguments.
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Function &F = *BB->getParent();
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FunctionLoweringInfo &FuncInfo = SDL.FuncInfo;
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if (BB == &F.front()) {
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SDOperand OldRoot = SDL.DAG.getRoot();
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std::vector<SDOperand> Args = TLI.LowerArguments(F, SDL.DAG);
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// If there were side effects accessing the argument list, do not do
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// anything special.
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if (OldRoot != SDL.DAG.getRoot()) {
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unsigned a = 0;
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for (Function::arg_iterator AI = F.arg_begin(), E = F.arg_end();
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AI != E; ++AI,++a)
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if (!AI->use_empty()) {
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SDL.setValue(AI, Args[a]);
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SDOperand Copy =
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CopyValueToVirtualRegister(SDL, AI, FuncInfo.ValueMap[AI]);
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UnorderedChains.push_back(Copy);
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}
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} else {
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// Otherwise, if any argument is only accessed in a single basic block,
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// emit that argument only to that basic block.
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unsigned a = 0;
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for (Function::arg_iterator AI = F.arg_begin(), E = F.arg_end();
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AI != E; ++AI,++a)
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if (!AI->use_empty()) {
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if (BasicBlock *BBU = IsOnlyUsedInOneBasicBlock(AI)) {
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FuncInfo.BlockLocalArguments.insert(std::make_pair(BBU,
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std::make_pair(AI, a)));
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} else {
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SDL.setValue(AI, Args[a]);
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SDOperand Copy =
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CopyValueToVirtualRegister(SDL, AI, FuncInfo.ValueMap[AI]);
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UnorderedChains.push_back(Copy);
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}
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}
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}
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}
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// See if there are any block-local arguments that need to be emitted in this
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// block.
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if (!FuncInfo.BlockLocalArguments.empty()) {
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std::multimap<BasicBlock*, std::pair<Argument*, unsigned> >::iterator BLAI =
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FuncInfo.BlockLocalArguments.lower_bound(BB);
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if (BLAI != FuncInfo.BlockLocalArguments.end() && BLAI->first == BB) {
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// Lower the arguments into this block.
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std::vector<SDOperand> Args = TLI.LowerArguments(F, SDL.DAG);
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// Set up the value mapping for the local arguments.
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for (; BLAI != FuncInfo.BlockLocalArguments.end() && BLAI->first == BB;
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++BLAI)
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SDL.setValue(BLAI->second.first, Args[BLAI->second.second]);
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// Any dead arguments will just be ignored here.
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}
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}
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}
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void SelectionDAGISel::BuildSelectionDAG(SelectionDAG &DAG, BasicBlock *LLVMBB,
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std::vector<std::pair<MachineInstr*, unsigned> > &PHINodesToUpdate,
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FunctionLoweringInfo &FuncInfo) {
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SelectionDAGLowering SDL(DAG, TLI, FuncInfo);
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std::vector<SDOperand> UnorderedChains;
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// Lower any arguments needed in this block.
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LowerArguments(LLVMBB, SDL, UnorderedChains);
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BB = FuncInfo.MBBMap[LLVMBB];
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SDL.setCurrentBasicBlock(BB);
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// Lower all of the non-terminator instructions.
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for (BasicBlock::iterator I = LLVMBB->begin(), E = --LLVMBB->end();
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I != E; ++I)
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SDL.visit(*I);
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// Ensure that all instructions which are used outside of their defining
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// blocks are available as virtual registers.
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for (BasicBlock::iterator I = LLVMBB->begin(), E = LLVMBB->end(); I != E;++I)
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if (!I->use_empty() && !isa<PHINode>(I)) {
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std::map<const Value*, unsigned>::iterator VMI =FuncInfo.ValueMap.find(I);
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if (VMI != FuncInfo.ValueMap.end())
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UnorderedChains.push_back(
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CopyValueToVirtualRegister(SDL, I, VMI->second));
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}
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// Handle PHI nodes in successor blocks. Emit code into the SelectionDAG to
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// ensure constants are generated when needed. Remember the virtual registers
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// that need to be added to the Machine PHI nodes as input. We cannot just
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// directly add them, because expansion might result in multiple MBB's for one
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// BB. As such, the start of the BB might correspond to a different MBB than
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// the end.
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//
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// Emit constants only once even if used by multiple PHI nodes.
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std::map<Constant*, unsigned> ConstantsOut;
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// Check successor nodes PHI nodes that expect a constant to be available from
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// this block.
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TerminatorInst *TI = LLVMBB->getTerminator();
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for (unsigned succ = 0, e = TI->getNumSuccessors(); succ != e; ++succ) {
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BasicBlock *SuccBB = TI->getSuccessor(succ);
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MachineBasicBlock::iterator MBBI = FuncInfo.MBBMap[SuccBB]->begin();
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PHINode *PN;
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// At this point we know that there is a 1-1 correspondence between LLVM PHI
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// nodes and Machine PHI nodes, but the incoming operands have not been
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// emitted yet.
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for (BasicBlock::iterator I = SuccBB->begin();
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(PN = dyn_cast<PHINode>(I)); ++I)
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if (!PN->use_empty()) {
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unsigned Reg;
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Value *PHIOp = PN->getIncomingValueForBlock(LLVMBB);
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if (Constant *C = dyn_cast<Constant>(PHIOp)) {
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unsigned &RegOut = ConstantsOut[C];
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if (RegOut == 0) {
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RegOut = FuncInfo.CreateRegForValue(C);
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UnorderedChains.push_back(
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CopyValueToVirtualRegister(SDL, C, RegOut));
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}
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Reg = RegOut;
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} else {
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Reg = FuncInfo.ValueMap[PHIOp];
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if (Reg == 0) {
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assert(isa<AllocaInst>(PHIOp) &&
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FuncInfo.StaticAllocaMap.count(cast<AllocaInst>(PHIOp)) &&
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"Didn't codegen value into a register!??");
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Reg = FuncInfo.CreateRegForValue(PHIOp);
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UnorderedChains.push_back(
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CopyValueToVirtualRegister(SDL, PHIOp, Reg));
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}
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}
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// Remember that this register needs to added to the machine PHI node as
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// the input for this MBB.
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unsigned NumElements =
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TLI.getNumElements(TLI.getValueType(PN->getType()));
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for (unsigned i = 0, e = NumElements; i != e; ++i)
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PHINodesToUpdate.push_back(std::make_pair(MBBI++, Reg+i));
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}
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}
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ConstantsOut.clear();
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// Turn all of the unordered chains into one factored node.
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if (!UnorderedChains.empty()) {
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UnorderedChains.push_back(SDL.getRoot());
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DAG.setRoot(DAG.getNode(ISD::TokenFactor, MVT::Other, UnorderedChains));
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}
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// Lower the terminator after the copies are emitted.
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SDL.visit(*LLVMBB->getTerminator());
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// Make sure the root of the DAG is up-to-date.
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DAG.setRoot(SDL.getRoot());
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}
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void SelectionDAGISel::SelectBasicBlock(BasicBlock *LLVMBB, MachineFunction &MF,
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FunctionLoweringInfo &FuncInfo) {
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SelectionDAG DAG(TLI, MF);
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CurDAG = &DAG;
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std::vector<std::pair<MachineInstr*, unsigned> > PHINodesToUpdate;
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// First step, lower LLVM code to some DAG. This DAG may use operations and
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// types that are not supported by the target.
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BuildSelectionDAG(DAG, LLVMBB, PHINodesToUpdate, FuncInfo);
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DEBUG(std::cerr << "Lowered selection DAG:\n");
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DEBUG(DAG.dump());
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// Second step, hack on the DAG until it only uses operations and types that
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// the target supports.
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DAG.Legalize();
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DEBUG(std::cerr << "Legalized selection DAG:\n");
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DEBUG(DAG.dump());
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// Third, instruction select all of the operations to machine code, adding the
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// code to the MachineBasicBlock.
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InstructionSelectBasicBlock(DAG);
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if (ViewDAGs) DAG.viewGraph();
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DEBUG(std::cerr << "Selected machine code:\n");
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DEBUG(BB->dump());
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// Next, now that we know what the last MBB the LLVM BB expanded is, update
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// PHI nodes in successors.
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for (unsigned i = 0, e = PHINodesToUpdate.size(); i != e; ++i) {
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MachineInstr *PHI = PHINodesToUpdate[i].first;
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assert(PHI->getOpcode() == TargetInstrInfo::PHI &&
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"This is not a machine PHI node that we are updating!");
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PHI->addRegOperand(PHINodesToUpdate[i].second);
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PHI->addMachineBasicBlockOperand(BB);
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}
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// Finally, add the CFG edges from the last selected MBB to the successor
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// MBBs.
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TerminatorInst *TI = LLVMBB->getTerminator();
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for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i) {
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MachineBasicBlock *Succ0MBB = FuncInfo.MBBMap[TI->getSuccessor(i)];
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BB->addSuccessor(Succ0MBB);
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}
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}
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