What is acceptable for -ffast-math? (Was: associative law in combine)

[dewar@gnat.com]

<<Exactly ... and it isn't at all rare that the programmer knows exactly
how much noise is in the input data (little or none) and the how much
accuracy he expects in the result (as much as possible!).
>>

No, no, "as much as possible" is often quite wrong. There are stable algorithms
that become unstable with unexpected extra precision.