private void EmitBranchComparison(bool branch, BinaryExpression node, Label label)
{
Debug.Assert(node.NodeType == ExpressionType.Equal || node.NodeType == ExpressionType.NotEqual);
Debug.Assert(!node.IsLiftedToNull);
// To share code paths, we want to treat NotEqual as an inverted Equal
var branchWhenEqual = branch == (node.NodeType == ExpressionType.Equal);
if (node.Method != null)
{
EmitBinaryMethod(node, CompilationFlags.EmitAsNoTail);
// EmitBinaryMethod takes into account the Equal/NotEqual
// node kind, so use the original branch value
EmitBranchOp(branch, label);
}
else if (ConstantCheck.IsNull(node.Left))
{
if (node.Right.Type.IsNullableType())
{
EmitAddress(node.Right, node.Right.Type);
_ilg.EmitHasValue(node.Right.Type);
}
else
{
Debug.Assert(!node.Right.Type.IsValueType);
EmitExpression(GetEqualityOperand(node.Right));
}
EmitBranchOp(!branchWhenEqual, label);
}
else if (ConstantCheck.IsNull(node.Right))
{
if (node.Left.Type.IsNullableType())
{
EmitAddress(node.Left, node.Left.Type);
_ilg.EmitHasValue(node.Left.Type);
}
else
{
Debug.Assert(!node.Left.Type.IsValueType);
EmitExpression(GetEqualityOperand(node.Left));
}
EmitBranchOp(!branchWhenEqual, label);
}
else if (node.Left.Type.IsNullableType() || node.Right.Type.IsNullableType())
{
EmitBinaryExpression(node);
// EmitBinaryExpression takes into account the Equal/NotEqual
// node kind, so use the original branch value
EmitBranchOp(branch, label);
}
else
{
EmitExpression(GetEqualityOperand(node.Left));
EmitExpression(GetEqualityOperand(node.Right));
if (branchWhenEqual)
{
_ilg.Emit(OpCodes.Beq, label);
}
else
{
_ilg.Emit(OpCodes.Ceq);
_ilg.Emit(OpCodes.Brfalse, label);
}
}
}