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

[Gabriel Dos_Reis]

| <<We're talking here of transformations which we do know able to
| drastically change the results.
| >>
| 
| Words like drastically are not particularly helpful in this discussion,
| plain "change" would be just fine.

Do you think changing 0.125 to 0.0 is not drastic?  I used
"drastically" to stress on the magnitude or error -- no other
conotation was implied. 

| THe issue is whether the "change" is worth the speed up.

I do fully understand that.

-- Gaby