public bool Optimize(ThreeAddressCode tac)
{
var isOptimized = false;
var directAssignments = new Dictionary <string, string>();
var blocks = new BasicBlocks();
blocks.SplitTACode(tac);
foreach (var block in blocks)
{
var currentNode = block.First;
while (currentNode != null)
{
if (currentNode.Value is TacAssignmentNode assignmentNode)
{
if (assignmentNode.Operation == null)
{
if (directAssignments.ContainsKey(assignmentNode.LeftPartIdentifier))
{
directAssignments.Remove(assignmentNode.LeftPartIdentifier);
}
if (!int.TryParse(assignmentNode.FirstOperand, out int firstOpValue))
{
var id = assignmentNode.LeftPartIdentifier;
var firstOp = assignmentNode.FirstOperand;
directAssignments.Add(id, firstOp);
}
}
if (directAssignments.ContainsKey(assignmentNode.FirstOperand))
{
assignmentNode.FirstOperand = directAssignments[assignmentNode.FirstOperand];
isOptimized = true;
}
if (assignmentNode.SecondOperand != null && directAssignments.ContainsKey(assignmentNode.SecondOperand))
{
assignmentNode.SecondOperand = directAssignments[assignmentNode.SecondOperand];
isOptimized = true;
}
if (directAssignments.ContainsKey(assignmentNode.LeftPartIdentifier) &&
assignmentNode.SecondOperand != null && assignmentNode.FirstOperand != null)
{
directAssignments.Remove(assignmentNode.LeftPartIdentifier);
}
}
currentNode = currentNode.Next;
}
}
return(isOptimized);
}
public bool Optimize(ThreeAddressCode tac)
{
var blocks = new BasicBlocks();
blocks.SplitTACode(tac);
var nodesByExpression = new Dictionary <string, LinkedListNode <TacNode> >();
var isOptimized = false;
foreach (var block in blocks)
{
nodesByExpression.Clear();
var currentNode = block.First;
while (currentNode != null)
{
if (currentNode.Value is TacAssignmentNode assignment &&
assignment.Operation != null &&
!int.TryParse(assignment.FirstOperand, out _) &&
!int.TryParse(assignment.SecondOperand, out _))
{
var expression = RightPartToString(assignment);
if (!nodesByExpression.ContainsKey(expression))
{
nodesByExpression.Add(expression, currentNode);
}
else
{
var node = nodesByExpression[expression];
var assignmentNode = node.Value as TacAssignmentNode;
if (IsPossibleToOptimize(node, currentNode,
assignmentNode.FirstOperand, assignmentNode.SecondOperand))
{
assignment.FirstOperand = assignmentNode.LeftPartIdentifier;
assignment.Operation = null;
assignment.SecondOperand = null;
isOptimized = true;
}
else
{
nodesByExpression[expression] = currentNode;
}
}
}
currentNode = currentNode.Next;
}
}
return(isOptimized);
}
public bool Optimize(BasicBlocks bb, IterationAlgorithm <TacNode> ita)
{
bool isUsed = false;
Dictionary <ThreeAddressCode, HashSet <TacNode> > IN = ita.InOut.In;
Dictionary <ThreeAddressCode, HashSet <TacNode> > OUT = ita.InOut.Out;
Dictionary <TacExpr, int> tacExprCount = new Dictionary <TacExpr, int>();
Dictionary <TacExpr, bool> varsExprChange = new Dictionary <TacExpr, bool>();
// ищем какие выражения нужно оптимизировать
foreach (var block in bb.BasicBlockItems)
{
foreach (TacNode node in block.TACodeLines)
{
if (node is TacAssignmentNode assign)
{
TacExpr expr = new TacExpr(assign);
if (!tacExprCount.Keys.Contains(expr))
{
tacExprCount.Add(expr, 1);
}
else
{
tacExprCount[expr] += 1;
}
}
}
}
// проводим оптимизацию
for (int blockInd = 0; blockInd < bb.BasicBlockItems.Count(); blockInd++)
{
var block = bb.BasicBlockItems[blockInd];
HashSet <TacExpr> inNode = TransformHashSetNodeToExpr(IN[block]);
HashSet <TacExpr> outNode = TransformHashSetNodeToExpr(OUT[block]);
var codeLine = block.TACodeLines.First;
while (codeLine != null)
{
var node = codeLine.Value;
if (node is TacAssignmentNode assign)
{
string assignId = assign.LeftPartIdentifier;
TacExpr expr = new TacExpr(assign);
// если выражений больше 1 делаем оптимизацию
if (tacExprCount[expr] > 1)
{
DictionarySetOrAdd(varsExprChange, expr, !inNode.Contains(expr));
// если это первая замена общего выражения
if (!idsForExprDic.Keys.Contains(expr))
{
// создаём переменную для общего выражения
string idName = TmpNameManager.Instance.GenerateTmpVariableName();
idsForExprDic.Add(expr, idName);
block.TACodeLines.AddBefore(block.TACodeLines.Find(node), expr.CreateAssignNode(idName));
AssignRightPartVarReplace(assign, idName);
varsExprChange[expr] = false;
}
else
{
string idName = idsForExprDic[expr];
// если это не замена общего выражения
if (assignId != idName)
{
AssignRightPartVarReplace(assign, idName);
}
// если выражение недоступно на входе
if (varsExprChange[expr])
{
block.TACodeLines.AddBefore(block.TACodeLines.Find(node), expr.CreateAssignNode(idName));
varsExprChange[expr] = false;
}
}
}
// для всех оптимизируемых выражений
foreach (var _expr in varsExprChange.Keys)
{
// если выражение недоступно на выходе и присваивание его изменяет
if (!outNode.Contains(_expr) && (_expr.FirstOperand == assignId || _expr.SecondOperand == assignId))
{
varsExprChange[_expr] = true;
}
}
}
}
}
return(isUsed);
}
