This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: Combiner fixes
On Tue, Aug 3, 2010 at 6:01 PM, Bernd Schmidt <bernds@codesourcery.com> wrote:
> On 08/03/2010 05:44 PM, Richard Guenther wrote:
>> It's not safe on RTL, please do not add FP reassociation there.
>> (config/i386/i386.c:ix86_expand_{round,trunc,...} would start
>> to break).
>
> Not a problem (I guess a !FLOAT_MODE_P || flag_associative_math test is
> needed), but I guess I don't understand how things would break - I see
> no multiply operations in these i386 functions. ?Can you elaborate?
It was just a general comment to re-associations of FP on RTL,
but more important is that we not start doing constant folding,
re-associating should be fine as long as they are valid without
any fancy math flags.
Richard.
>
> Bernd
>