[llvm-commits] [llvm] r77407 - in /llvm/trunk: include/llvm/IntrinsicsX86.td lib/Target/X86/X86ISelLowering.cpp lib/Target/X86/X86ISelLowering.h lib/Target/X86/X86InstrSSE.td test/CodeGen/X86/sse41.ll

Eric Christopher echristo at apple.com
Wed Jul 29 10:53:21 PDT 2009


On Jul 28, 2009, at 10:49 PM, Chris Lattner wrote:

>
> On Jul 28, 2009, at 10:44 PM, Evan Cheng wrote:
>
>>> Ok, that's what I feared.  This means that we need conditional flag
>>> liveness stuff?  Is there a way to know (e.g. in regalloc, when  
>>> doing
>>> a spill) that only one flag is used?  Do we have flag subregs?
>>
>> Not yet.
>>
>> If we care about this, the solution is to lower ptestz and ptestc,
>> ptestnzc to different x86isd nodes.
>
> Yes, that would work for commuting at isel time to match the load.
> This wouldn't work for commuting to fold a reload.

Yeah, I originally had it this way (multiple isd nodes) but combined  
them as unnecessarily complicated - shouldn't be a problem to separate  
them back out.

-eric



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