For (a), it would probably look like the late 90's dot com bubble runup, except that it wouldn't end with a bubble burst and most of the companies going under, instead it would just keep going, while world dramatically changed.
For (b), I don't think we would really know until it had started, at which point things would go bad very, very quickly. I doubt that you could use price movements far in advance to predict it coming.
In general, markets can go down in price much faster than they went up. Scenario (a) would look like a continual parabolic rise, while (b) would just be a massive crash.
For (a), it would probably look like the late 90's dot com bubble runup
Why? In both cases money becomes meaningless post-singularity.
If you expect a happy singularity in the near future, you should actually pull your money out of investments and spend it all on consumption (or risk mitigation).
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