A performance predicament

[Richard Eisenberg]

On Mar 11, 2016, at 12:04 PM, Simon Peyton Jones <simonpj at microsoft.com> wrote:

> Profiling prevents optimisation!  

I didn't know that. Why does it do this? It defeats the point of profiling a bit if we can't optimize. I just assumed the optimizer looks through the SCCs, preserving them, but that otherwise SCCs don't get in the way.

Anyway, helpful to know. Is this fact documented in the manual?

Thanks!
Richard