AMD wasn't even in the picture at that time really. Meaning their marketshare of desktop pc's were so low that no one had them. Back in those days it was Intel vs Cyrix.
AMD sold a ton of 386 and 486 processors and held much more market share than Cyrix. They were also very successful with their K6 and K6-2 Pentium competitor processors.
AMD absolutely was in the picture - they sold a ton of high-speed/low-cost 286 CPUs. In the mid and late 80s there was such a thing as a 286 12 MHz which sold for the same price as a much slower Intel part.
I'm referring to the whole time frame before the Cyrix 5x86 and similar were even a thing... There were plenty of AMD 286 and 386 CPUs sold in the early 1990s.