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Re: fast-math optimization question
- From: Andrew Pinski <pinskia at gmail dot com>
- To: Steve Ellcey <sellcey at mips dot com>
- Cc: GCC Mailing List <gcc at gcc dot gnu dot org>
- Date: Thu, 9 Oct 2014 11:40:49 -0700
- Subject: Re: fast-math optimization question
- Authentication-results: sourceware.org; auth=none
- References: <10940e4b-0c5c-4a2a-9432-6385e9590fb4 at BAMAIL02 dot ba dot imgtec dot org> <CA+=Sn1mkOCmPxPmn-RYkE+CJBrQ=8U7O07RUj8wwc6KyuXzrJQ at mail dot gmail dot com> <1412879523 dot 28410 dot 133 dot camel at ubuntu-sellcey>
On Thu, Oct 9, 2014 at 11:32 AM, Steve Ellcey <sellcey@mips.com> wrote:
> On Thu, 2014-10-09 at 11:27 -0700, Andrew Pinski wrote:
>
>> > Is there a reason why GCC couldn't (under -ffast-math) call the single
>> > precision routines for the first case?
>>
>> There is no reason why it could not. The reason why it does not
>> currently is because there is no pass which does the demotion and the
>> only case of demotion that happens is with a simple
>> (float)function((double)float_val);
>>
>> Thanks,
>> Andrew
>
> Do you know which pass does the simple
> '(float)function((double)float_val)' demotion? Maybe that would be a
> good place to extend things.
Yes builtins.c.
>
> Steve Ellcey
>