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Re: j0_downward failures on i686 with gcc 6.
- From: Szabolcs Nagy <szabolcs dot nagy at arm dot com>
- To: Joseph Myers <joseph at codesourcery dot com>, Carlos O'Donell <carlos at redhat dot com>
- Cc: GNU C Library <libc-alpha at sourceware dot org>, <nd at arm dot com>
- Date: Tue, 1 Mar 2016 16:37:26 +0000
- Subject: Re: j0_downward failures on i686 with gcc 6.
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On 01/03/16 15:42, Joseph Myers wrote:
> On Tue, 1 Mar 2016, Carlos O'Donell wrote:
>
>> Joseph,
>>
>> On i686 using GCC 6.0 I see some additional +1 ULP changes in j0.
>>
>> Does this seem like normal compiler-induced changed in precision?
>
> Yes - on i686, different register allocation choices affecting which
> intermediate values are stored in excess precision.
>
i think that should not happen with -std=c99, if
FLT_EVAL_METHOD==2 all intermediate values must be
in long double precision.