llvm dev - Nov 2008 - [LLVMdev] changing -mattr behavior with mmx and sse

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.

Thanks,
   -- Mon Ping

Might you instead consider just adding a -disable-mmx option?

Preston

On Thu, 2008-20-11 at 02:57 -0500, 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.
> 
> Thanks,
>    -- Mon Ping
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev

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...

On Nov 20, 2008, at 8:31 AM, Preston Gurd wrote:
> Might you instead consider just adding a -disable-mmx option?
I agree, this is a better approach.  This distinguishes between  
capabilities of the chip and the desire to codegen specific vectors  
one way or another.

-Chris
>
> Preston
>
> On Thu, 2008-20-11 at 02:57 -0500, 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.
>>
>> Thanks,
>>   -- Mon Ping
>> _______________________________________________
>> LLVM Developers mailing list
>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev

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...
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev