Re: [PATCH] Fix pr67963

[Uros Bizjak <ubizjak at gmail dot com>]

On Fri, Oct 16, 2015 at 8:43 AM, Uros Bizjak <ubizjak@gmail.com> wrote:
> On Thu, Oct 15, 2015 at 9:30 PM, Uros Bizjak <ubizjak@gmail.com> wrote:
>
>>>>> Do we support -O2 -march=lakemont with
>>>>>
>>>>> __attribute__((target("arch=silvermont")))
>>>>
>>>> Hm, no.
>>>>
>>>
>>> Do we issue an error or silently ignore
>>> __attribute__((target("arch=silvermont")))?
>>> If we don't support it, should we support
>>>
>>> -O2 -march=silvermont
>>>
>>> __attribute__((target("arch=lakemont")))
>>
>> Actually, we have to re-initialize:
>>
>>   opts->x_target_flags
>>     |= (TARGET_DEFAULT | TARGET_SUBTARGET_DEFAULT) & ~opts_set->x_target_flags;
>>
>> just before TARGET_SUBTARGET{32,64}_DEFAULT processing, and it will work.
>
> No, this won't work. The value of MASK_NO_FANCY_MATH depend on
> MASK_80387setting, and once fancy math bit is set, it couldn't be
> cleared for march != lakemont.
>
> It looks just like we want to error out when lakemont is enabled with -m80387.

Like in the attached patch, that also slightly improves existing error
reporting.

Uros.

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