GCC and Floating-Point

[Vincent Lefevre]

On 2005-05-26 09:14:40 -0400, Daniel Berlin wrote:
> On Thu, 26 May 2005, Vincent Lefevre wrote:
> >On 2005-05-25 19:27:21 +0200, Allan Sandfeld Jensen wrote:
> >>Yes. I still don't understand why gcc doesn't do -ffast-math by
> >>default like all other compilers.
> >
> >No! And I really don't think that other compilers do that.
> 
> Have you looked, or are you just guessing?

Just guessing (I said "I don't think").

> I know for a fact that XLC does it at -O3+, and unless i'm 
> misremembering, icc does it at -O2+.

But do they use -O3 and -O2 by default?

Even if they don't, maths optimization breaking IEEE-754 (if they
claim to support it) is bad, IMHO, but well...

I don't have these compilers to test them. If you have simple C code
showing how they "break" it, I'd be interesting...

-- 
Vincent Lefèvre <vincent@vinc17.org> - Web: <http://www.vinc17.org/>
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Work: CR INRIA - computer arithmetic / SPACES project at LORIA