Yeah, because the only way to achieve performance in 1980's C on 16 bit platforms was to litter it with inline Assembly, thus UB based optimisation was born to win all those SPEC benchmarks in computer magazines.
Funny thing in that the same thing stopping people to write those crazy¹ optimizers at the 1980s was exactly the lack of capacity of the computers to run them.
What means that they appeared exactly at the time the need for them became niche. And yet everybody adopted them due to the strong voodoo bias we all have at computer-related tasks.
1 - They are crazy. They believe the code has no UB even though they can prove it has.
