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);
}