C++ LoadInst::isVolatile方法代码示例

void FuncTransform::visitLoadInst(LoadInst &LI) {
  //
  // Record the use of the pool handle for the pointer being dereferenced.
  //
  if (Value *PH = getPoolHandle(LI.getOperand(0)))
    AddPoolUse(LI, PH, PoolUses);

  //
  // If this is a volatile load, then record a use of the pool handle for the
  // loaded value, even if it is never used.
  //
  if (LI.isVolatile()) {
    if (Value *PH = getPoolHandle(&LI))
      AddPoolUse (LI, PH, PoolUses);
  }

  visitInstruction(LI);
}

// Not an instruction handled below to turn into a vector.
//
// TODO: Check isTriviallyVectorizable for calls and handle other
// instructions.
static bool canVectorizeInst(Instruction *Inst, User *User) {
  switch (Inst->getOpcode()) {
  case Instruction::Load: {
    LoadInst *LI = cast<LoadInst>(Inst);
    // Currently only handle the case where the Pointer Operand is a GEP so check for that case.
    return isa<GetElementPtrInst>(LI->getPointerOperand()) && !LI->isVolatile();
  }
  case Instruction::BitCast:
  case Instruction::AddrSpaceCast:
    return true;
  case Instruction::Store: {
    // Must be the stored pointer operand, not a stored value, plus
    // since it should be canonical form, the User should be a GEP.
    StoreInst *SI = cast<StoreInst>(Inst);
    return (SI->getPointerOperand() == User) && isa<GetElementPtrInst>(User) && !SI->isVolatile();
  }
  default:
    return false;
  }
}

//.........这里部分代码省略.........
    Instruction *alloc = NULL;
    Value *globalPtr = NULL;

    // create temporary alloca space to communicate to/from.
    alloc = makeAlloca(int8Ty, "agg.tmp", insertBefore,
                       Range.End-Range.Start, Alignment);

    // Generate the old and new base pointers before we output
    // anything else.
    {
      Type* iPtrTy = TD->getIntPtrType(alloc->getType());
      Type* iNewBaseTy = TD->getIntPtrType(alloc->getType());
      oldBaseI = builder.CreatePtrToInt(StartPtr, iPtrTy, "agg.tmp.oldb.i");
      newBaseI = builder.CreatePtrToInt(alloc, iNewBaseTy, "agg.tmp.newb.i");
    }

    // If storing, do the stores we had into our alloca'd region.
    if( isStore ) {
      for (SmallVector<Instruction*, 16>::const_iterator
           SI = Range.TheStores.begin(),
           SE = Range.TheStores.end(); SI != SE; ++SI) {
        StoreInst* oldStore = cast<StoreInst>(*SI);

        if( DebugThis ) {
          errs() << "have store in range:";
          oldStore->dump();
        }

        Value* ptrToAlloc = rebasePointer(oldStore->getPointerOperand(),
                                          StartPtr, alloc, "agg.tmp",
                                          &builder, *TD, oldBaseI, newBaseI);
        // Old load must not be volatile or atomic... or we shouldn't have put
        // it in ranges
        assert(!(oldStore->isVolatile() || oldStore->isAtomic()));
        StoreInst* newStore =
          builder.CreateStore(oldStore->getValueOperand(), ptrToAlloc);
        newStore->setAlignment(oldStore->getAlignment());
        newStore->takeName(oldStore);
      }
    }

    // cast the pointer that was load/stored to i8 if necessary.
    if( StartPtr->getType()->getPointerElementType() == int8Ty ) {
      globalPtr = StartPtr;
    } else {
      globalPtr = builder.CreatePointerCast(StartPtr, globalInt8PtrTy, "agg.cast");
    }

    // Get a Constant* for the length.
    Constant* len = ConstantInt::get(sizeTy, Range.End-Range.Start, false);

    // Now add the memcpy instruction
    unsigned addrSpaceDst,addrSpaceSrc;
    addrSpaceDst = addrSpaceSrc = 0;
    if( isStore ) addrSpaceDst = globalSpace;
    if( isLoad ) addrSpaceSrc = globalSpace;

    Type *types[3];
    types[0] = PointerType::get(int8Ty, addrSpaceDst);
    types[1] = PointerType::get(int8Ty, addrSpaceSrc);
    types[2] = sizeTy;

    Function *func = Intrinsic::getDeclaration(M, Intrinsic::memcpy, types);

    Value* args[5]; // dst src len alignment isvolatile
    if( isStore ) {

bool NVPTXLowerAggrCopies::runOnFunction(Function &F) {
  SmallVector<LoadInst *, 4> aggrLoads;
  SmallVector<MemTransferInst *, 4> aggrMemcpys;
  SmallVector<MemSetInst *, 4> aggrMemsets;

  DataLayout *TD = &getAnalysis<DataLayout>();
  LLVMContext &Context = F.getParent()->getContext();

  //
  // Collect all the aggrLoads, aggrMemcpys and addrMemsets.
  //
  //const BasicBlock *firstBB = &F.front();  // first BB in F
  for (Function::iterator BI = F.begin(), BE = F.end(); BI != BE; ++BI) {
    //BasicBlock *bb = BI;
    for (BasicBlock::iterator II = BI->begin(), IE = BI->end(); II != IE;
        ++II) {
      if (LoadInst * load = dyn_cast<LoadInst>(II)) {

        if (load->hasOneUse() == false) continue;

        if (TD->getTypeStoreSize(load->getType()) < MaxAggrCopySize) continue;

        User *use = *(load->use_begin());
        if (StoreInst * store = dyn_cast<StoreInst>(use)) {
          if (store->getOperand(0) != load) //getValueOperand
          continue;
          aggrLoads.push_back(load);
        }
      } else if (MemTransferInst * intr = dyn_cast<MemTransferInst>(II)) {
        Value *len = intr->getLength();
        // If the number of elements being copied is greater
        // than MaxAggrCopySize, lower it to a loop
        if (ConstantInt * len_int = dyn_cast < ConstantInt > (len)) {
          if (len_int->getZExtValue() >= MaxAggrCopySize) {
            aggrMemcpys.push_back(intr);
          }
        } else {
          // turn variable length memcpy/memmov into loop
          aggrMemcpys.push_back(intr);
        }
      } else if (MemSetInst * memsetintr = dyn_cast<MemSetInst>(II)) {
        Value *len = memsetintr->getLength();
        if (ConstantInt * len_int = dyn_cast<ConstantInt>(len)) {
          if (len_int->getZExtValue() >= MaxAggrCopySize) {
            aggrMemsets.push_back(memsetintr);
          }
        } else {
          // turn variable length memset into loop
          aggrMemsets.push_back(memsetintr);
        }
      }
    }
  }
  if ((aggrLoads.size() == 0) && (aggrMemcpys.size() == 0)
      && (aggrMemsets.size() == 0)) return false;

  //
  // Do the transformation of an aggr load/copy/set to a loop
  //
  for (unsigned i = 0, e = aggrLoads.size(); i != e; ++i) {
    LoadInst *load = aggrLoads[i];
    StoreInst *store = dyn_cast<StoreInst>(*load->use_begin());
    Value *srcAddr = load->getOperand(0);
    Value *dstAddr = store->getOperand(1);
    unsigned numLoads = TD->getTypeStoreSize(load->getType());
    Value *len = ConstantInt::get(Type::getInt32Ty(Context), numLoads);

    convertTransferToLoop(store, srcAddr, dstAddr, len, load->isVolatile(),
                          store->isVolatile(), Context, F);

    store->eraseFromParent();
    load->eraseFromParent();
  }

  for (unsigned i = 0, e = aggrMemcpys.size(); i != e; ++i) {
    MemTransferInst *cpy = aggrMemcpys[i];
    Value *len = cpy->getLength();
    // llvm 2.7 version of memcpy does not have volatile
    // operand yet. So always making it non-volatile
    // optimistically, so that we don't see unnecessary
    // st.volatile in ptx
    convertTransferToLoop(cpy, cpy->getSource(), cpy->getDest(), len, false,
                          false, Context, F);
    cpy->eraseFromParent();
  }

  for (unsigned i = 0, e = aggrMemsets.size(); i != e; ++i) {
    MemSetInst *memsetinst = aggrMemsets[i];
    Value *len = memsetinst->getLength();
    Value *val = memsetinst->getValue();
    convertMemSetToLoop(memsetinst, memsetinst->getDest(), len, val, Context,
                        F);
    memsetinst->eraseFromParent();
  }

  return true;
}

Function * futamurize( const Function * orig_func, DenseMap<const Value*, Value*> &argmap, std::set<const unsigned char *> &constant_addresses_set )
{
	LLVMContext &context = getGlobalContext();
	
	
	// Make a copy of the function, removing constant arguments
	Function * specialized_func = CloneFunction( orig_func, argmap );
	specialized_func->setName( orig_func->getNameStr() + "_1" );
	
	// add it to our module
	LLVM_Module->getFunctionList().push_back( specialized_func );
	
	printf("\nspecialized_func = %p <%s>\n", specialized_func, specialized_func->getName().data());
	//~ specialized_func->dump();

	// Optimize it
	FunctionPassManager PM( LLVM_Module );
	createStandardFunctionPasses( &PM, 3 );
	
	PM.add(createScalarReplAggregatesPass());  // Break up aggregate allocas
	PM.add(createInstructionCombiningPass());  // Cleanup for scalarrepl.
	PM.add(createJumpThreadingPass());         // Thread jumps.
	PM.add(createCFGSimplificationPass());     // Merge & remove BBs
	PM.add(createInstructionCombiningPass());  // Combine silly seq's
	PM.add(createTailCallEliminationPass());   // Eliminate tail calls
	PM.add(createCFGSimplificationPass());     // Merge & remove BBs
	PM.add(createReassociatePass());           // Reassociate expressions
	PM.add(createLoopRotatePass());            // Rotate Loop
	PM.add(createLICMPass());                  // Hoist loop invariants
	PM.add(createLoopUnswitchPass( false ));
	PM.add(createInstructionCombiningPass());
	PM.add(createIndVarSimplifyPass());        // Canonicalize indvars
	PM.add(createLoopDeletionPass());          // Delete dead loops
	PM.add(createLoopUnroll2Pass());            // Unroll small loops
	PM.add(createInstructionCombiningPass());  // Clean up after the unroller
	PM.add(createGVNPass());                   // Remove redundancies
	PM.add(createMemCpyOptPass());             // Remove memcpy / form memset
	PM.add(createSCCPPass());                  // Constant prop with SCCP
	PM.add(createPromoteMemoryToRegisterPass()); 
	PM.add(createConstantPropagationPass());            
	PM.add(createDeadStoreEliminationPass());            
	PM.add(createAggressiveDCEPass());            
	PM.add(new MemoryDependenceAnalysis());            
	//~ PM.add(createAAEvalPass());              
	
	const PassInfo * pinfo = Pass::lookupPassInfo( "print-alias-sets" );
	if( !pinfo ) { printf( "print-alias-sets not found\n" ); exit(-1); }
	PM.add( pinfo->createPass() );
	
	FunctionPassManager PM_Inline( LLVM_Module );
	PM_Inline.add(createSingleFunctionInliningPass());            
	
	bool Changed = false;
	int iterations = 2;
	int inline_iterations = 6;
	
	do
	{
		Changed = false;
		
		// first do some optimizations
		PM.doInitialization();
		PM.run( *specialized_func );
		PM.doFinalization();
		
		// Load from Constant Memory detection
		const TargetData *TD = LLVM_EE->getTargetData();
		
		for (inst_iterator I = inst_begin(specialized_func), E = inst_end(specialized_func); I != E; ++I) 
		{
			Instruction * inst = (Instruction *) &*I;

			// get all Load instructions
			LoadInst * load = dyn_cast<LoadInst>( inst );
			if( !load ) continue;
			if( load->isVolatile() ) continue;

			if (load->use_empty()) continue;        // Don't muck with dead instructions...

			// get the address loaded by load instruction
			Value *ptr_value = load->getPointerOperand();
			
			// we're only interested in constant addresses
			ConstantExpr * ptr_constant_expr =  dyn_cast<ConstantExpr>( ptr_value );
			if( !ptr_constant_expr ) continue;			
			ptr_constant_expr->dump();
			
			// compute real address of constant pointer expression
			Constant * ptr_constant = ConstantFoldConstantExpression( ptr_constant_expr, TD );
			if( !ptr_constant ) continue;
			ptr_constant->dump();
			
			// convert to int constant
			ConstantInt *int_constant =  dyn_cast<ConstantInt>( ConstantExpr::getPtrToInt( ptr_constant, Type::getInt64Ty( context )));
			if( !int_constant ) continue;
			int_constant->dump();
			
			// get data size
			int data_length = TD->getTypeAllocSize( load->getType() );
			ptr_value->getType()->dump();
//.........这里部分代码省略.........