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Re: Reporting bugs: there is nothing to gain infrustrating reporters
On Sat, 2005-06-18 at 17:37 -0400, Robert Dewar wrote:
> > Changing the default rounding of the processor will make code less
> > efficient?
> Yes, if you have to change it backwards and forwards for float and
> double
Quite rare. Only usage I've seen is for tabulation when you want
to save storage space but there it won't be an issue since you're
explicitely storing to memory.
> ... and if you insist on getting the range right as well as
> the precision, then you have to do extra stores.
If you code run in extra range issue then you'll get "expected"
results on x86 and it will fail everywhere else, a nice
way to detect those issues indeed (and you won't face
this if you developped your code on non x86).
> Changing the rounding mode alone does not give what people call IEEE behavior.
I agree, but in 99.9% of the case it will do what people expect.
For the remaining 0.1% of the case, we're facing expert code and
experts can look into the magic manual and find the right
flags/pragma/libraries/whatever :).
Anyway, default situation is unlikely to change, and x86_64 ABI
default to SSE2 plus it will soon be hard to find reasonably powerful
x86 only harware out there...
Laurent