[LLVMdev] changing -mattr behavior with mmx and sse

[Stefanus Du Toit]

For what it's worth, we've been operating in this mode for a while now  
(using a somewhat brute force local patch), and haven't seen any  
issues with it so far.

On 20-Nov-08, at 1:09 PM, Mon Ping Wang wrote:
> Hi Dale,
>
> I will not change the default.  I would dislike to see any regressions
> due to this type of change.
>
> -- Mon Ping
>
> On Nov 20, 2008, at 10:12 AM, Dale Johannesen wrote:
>
>>
>> On Nov 19, 2008, at 11:57 PMPST, Mon Ping Wang wrote:
>>
>>> Hi,
>>>
>>> When setting -mattr option on X86, I would like to treat MMX
>>> separately from SSE levels. This would allow a client who sets the
>>> attributes directly to set the SSE level independent of MMX, e.g.,
>>> llc
>>> -march=x86 -mattr=sse41, one would get sse4.1 with mmx disabled  
>>> while
>>> llc -march=x86 -mattr=mmx -mattr=sse42 will get mmx and sse42.  If
>>> anyone objects to this change, please let me know.
>>
>> I don't object, but please don't change the defaults.
>> You're likely to find places the SSE code assumes MMX exists...
>>
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--
Stefanus Du Toit <stefanus.dutoit at rapidmind.com>
   RapidMind Inc.
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