[llvm-dev] DFAPacketizer assert failure

[Rail Shafigulin via llvm-dev]

On Mon, Nov 16, 2015 at 2:29 PM, Krzysztof Parzyszek <
kparzysz at codeaurora.org> wrote:

> On 11/16/2015 3:49 PM, Rail Shafigulin wrote:
>
>>
>>     Does the instruction that is being added have an itinerary
>>     associated with it?
>>
>> So I checked again, and it turns out that it does have an itinerary
>> associated with it. However it is a pseudo instruction. Does the
>> packetizer do something special with the pseudo instructions? I didn't
>> see any special code, but I could have missed it.
>>
>
> The packetizer should not do anything with these---they should not be
> inserted into a bundle.  I'm not sure if the code in DFAPacketizer.cpp does
> that or not.  In the Hexagon backend we originally treated CFI instructions
> as "solo", i.e. they could not be packetized with any other instruction.
> Now we simply delay the generation of these instructions until after
> packetization.  The reason for this is that two instructions that could be
> packetized together were not packetized together if there was an CFI
> instruction in between.  This was causing different code to be generated
> with the CFI instructions present.
>
> In general, most pseudo instructions should have been expanded into real
> instructions by the time the packetizer runs. For exeptional cases, you can
> treat them as not being packetizable with any other instructions.
>
>
> -Krzysztof
>
> --
>

Thanks for the explanation.

-- 
R
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