The growing demand for AI-focused semiconductors is proving to be a tailwind for both of these companies.Arm Holdings (ARM -1.21%) and Advanced Micro Devices (AMD -1.50%) have witnessed contrasting fortunes on the stock market in 2024, with one of these companies sitting on healthy gains so far this year while the other one underperforms the broader semiconductor market.Arm stock has jumped 50% this year. AMD, on the other hand, has lost 10% of its value compared to the 10% gains clocked by the PHLX Semicon ...