// Generates optimized OrElse with branch == true
// or optimized AndAlso with branch == false
private void EmitBranchOr(bool branch, BinaryExpression node, Label label)
{
// if (left OR right) branch label
if (ConstantCheck.IsConstant(node.Left, branch))
{
_ilg.Emit(OpCodes.Br, label);
}
else
{
if (!ConstantCheck.IsConstant(node.Left, !branch))
{
EmitExpressionAndBranch(branch, node.Left, label);
}
if (ConstantCheck.IsConstant(node.Right, branch))
{
_ilg.Emit(OpCodes.Br, label);
}
else if (!ConstantCheck.IsConstant(node.Right, !branch))
{
EmitExpressionAndBranch(branch, node.Right, label);
}
}
}
// Generates optimized AndAlso with branch == true
// or optimized OrElse with branch == false
private void EmitBranchAnd(bool branch, BinaryExpression node, Label label)
{
// if (left AND right) branch label
if (!ConstantCheck.IsConstant(node.Left, !branch) && !ConstantCheck.IsConstant(node.Right, !branch))
{
if (ConstantCheck.IsConstant(node.Left, branch))
{
EmitExpressionAndBranch(branch, node.Right, label);
}
else if (ConstantCheck.IsConstant(node.Right, branch))
{
EmitExpressionAndBranch(branch, node.Left, label);
}
else
{
// if (left) then
// if (right) branch label
// endif
Label endif = _ilg.DefineLabel();
EmitExpressionAndBranch(!branch, node.Left, endif);
EmitExpressionAndBranch(branch, node.Right, label);
_ilg.MarkLabel(endif);
}
}
}