[llvm-dev] generating multiple instructions for a single pattern

[Nagaraju Mekala via llvm-dev]

Hi Jatin, Bruce, David

  Thanks for your valuable suggestions.
  I have defined the patterns to match the custom DAG nodes and it
worked for me.

Thanks,
Nagaraju

On Fri, Mar 2, 2018 at 8:32 PM, Jatin Bhateja <jatin.bhateja at gmail.com> wrote:
> Other suggestions
>
> 1/ Write a separate MI pass to split the macro MI which was generated
> earlier as a result of ISel to multiple MIs.
> 2/ Take the decision of splitting later in the pipeling during MC lowering.
>
> Decision about when you need to split should be driven by your intent to do
> any further processing over constituent instruction.
>
> ~ Jatin
>
>
>
> On Fri, Mar 2, 2018 at 8:19 PM, Jatin Bhateja <jatin.bhateja at gmail.com>
> wrote:
>>
>> Hi Nagaraju,
>>
>> Few suggestions split this into following steps.
>>
>> 1/ DAG Legalization : Custom lower the instruction (branch in your case)
>> appropriately in legalization to target specific DAG nodes and glue the
>> nodes together which you want scheduler should schedule together.
>>
>> 2/ Instruction Selection : Define patterns to match the custom DAG nodes.
>>
>> Thus actual decision of creating multiple instruction is taken care by
>> legalizer and selection phase is dump which does pattern matching over
>> whatever DAG is
>> feeded to it.
>>
>> Thanks,
>> Jatin
>>
>> On Fri, Mar 2, 2018 at 4:39 PM, Nagaraju Mekala via llvm-dev
>> <llvm-dev at lists.llvm.org> wrote:
>>>
>>> Hi All,
>>>
>>>    I am working on a target which requires to generated two
>>> instructions for a single branch instruction.
>>> ex:
>>>    imm 1
>>>    br r4,0xabcd
>>>    branch address is 0x1abcd, imm has the upper 16 bits and br has
>>> lower 16 bits.
>>>
>>>   Can anyone let me know how to write these kind of patterns in the
>>> InstrInfo.td file.
>>>
>>> Thanks in Advance,
>>> Nagaraju
>>> _______________________________________________
>>> LLVM Developers mailing list
>>> llvm-dev at lists.llvm.org
>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>
>>
>