[llvm-dev] Is there any pass existing in llvm which does machine copy propogation ?

[Krzysztof Parzyszek via llvm-dev]

At the moment X86 does not have a register unit for the upper part of 
EAX (not covered by AX), which makes AX and EAX have the same set of 
register units. This leads to incorrect results with RDF because writing 
to AX preserves the upper part of EAX, and this currently cannot be 
represented. This is somewhat of a known limitation.

Adding cc:Quentin: maybe he'll say what he thinks about adding that unit.

-Krzysztof

On 7/24/2017 12:32 AM, Rai, Deepali via llvm-dev wrote:
> Thanks Krzysztof for the quick response.
> I looking for x86 target.
> 
> Thanks,
> -Deepali
> -----Original Message-----
> From: llvm-dev [mailto:llvm-dev-bounces at lists.llvm.org] On Behalf Of Krzysztof Parzyszek via llvm-dev
> Sent: Friday, July 21, 2017 7:55 PM
> To: llvm-dev at lists.llvm.org
> Subject: Re: [llvm-dev] Is there any pass existing in llvm which does machine copy propogation ?
> 
> Hexagon has RDFCopy.cpp that does that.  It uses RDF framework that is currently under lib/Target/Hexagon, but is meant to be target-independent.  See https://reviews.llvm.org/D29295.
> 
> What target are you interested in?
> 
> -Krzysztof
> 
> 
> On 7/21/2017 2:18 AM, Rai, Deepali via llvm-dev wrote:
>> Hi All,
>>
>> I was looking into MachineCopyPropagationPass.ccp file in llvm, which
>> in first look, looks likes to me doing only redundant copy elimination
>> in same basic block.
>>
>> I am interested in any pass which is doing copy propogation across the
>> basic block in a function.
>>
>> Let me know if any such pass exist ?
>>
>> Thanks,
>>
>> Deepali
>>
>>
>>
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> 
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