[LLVMdev] adding comment

[Eric Christopher]

We've generally used -fast-isel-verbose and -fast-isel-abort to deal
with a lot of the testing of fast-isel these days, but if you can show
a compelling use case for testing where you can't write tests
otherwise then being able to increase our test coverage via other
means is always welcome.

-eric

On Tue, Apr 22, 2014 at 8:34 AM, Reed Kotler <reed.kotler at imgtec.com> wrote:
> Nice. I suggest you submit the patch to llvm commits.
>
> That will make more realistic make check tests for fast-isel and make it
> easy to see which code is emitted by fast-isel
> and normal isel.
>
>
> On 04/22/2014 03:39 AM, Daniel Sanders wrote:
>>
>> I tried out CommentFlag and it looks ideal for this purpose. The attached
>> patch adds a FastISel flag and prints it in the AsmPrinter and the IR dump.
>> You can then call MachineInstr::setAsmPrinterFlag(MachineInstr::FastISel) to
>> set the flag.
>>
>> Some passes seem to be stripping the comment flags though. The one I
>> noticed is the pseudo-instruction expansion pass:
>>         # *** IR Dump After Machine Copy Propagation Pass ***:
>>         # Machine code for function retfloat: Post SSA
>>
>>         BB#0: derived from LLVM BB %entry
>>                 RetRA; comment-flags: FastISel
>>
>>         # End machine code for function retfloat.
>>
>>         # *** IR Dump After Post-RA pseudo instruction expansion pass ***:
>>         # Machine code for function retfloat: Post SSA
>>
>>         BB#0: derived from LLVM BB %entry
>>                 RET %RA
>>
>>         # End machine code for function retfloat.
>>
>>> -----Original Message-----
>>> From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu]
>>> On Behalf Of Reed Kotler
>>> Sent: 17 April 2014 16:30
>>> To: LLVMdev at cs.uiuc.edu
>>> Subject: Re: [LLVMdev] adding comment
>>>
>>> Maybe adding it to CommentFlag would be slightly better.
>>>
>>> On 04/17/2014 02:23 AM, Daniel Sanders wrote:
>>>>
>>>> Would adding a flag to MachineInstr::MIFlag do the trick? I'm thinking
>>>> that
>>>
>>> fast isel could ensure that a flag (e.g. MIFlag::FastISel) is added to
>>> the
>>> instructions it creates, then the instruction printer could optionally
>>> emit a
>>> comment for instructions that have this flag.
>>>>>
>>>>> -----Original Message-----
>>>>> From: llvmdev-bounces at cs.uiuc.edu
>>>>> [mailto:llvmdev-bounces at cs.uiuc.edu]
>>>>> On Behalf Of Reed Kotler
>>>>> Sent: 16 April 2014 22:17
>>>>> To: LLVMdev at cs.uiuc.edu
>>>>> Subject: Re: [LLVMdev] adding comment
>>>>>
>>>>> On 04/16/2014 02:06 PM, reed kotler wrote:
>>>>>>
>>>>>> Is there a simple way to add a comment in the machine instructions
>>>>>> of a basic block?
>>>>>>
>>>>>> Ideally something that can be used with machine instruction builder.
>>>>>>
>>>>>> Tia.
>>>>>>
>>>>>> Reed
>>>>>
>>>>> In this case, I am working on the fast instruction selector for mips.
>>>>>
>>>>> I want to be able to tag instructions or regions of instructions that
>>>>> are emitted by the fast instruction selector as opposed to the normal
>>>>> mechanism.
>>>>>
>>>>> In fast instruction selector can always report that it cannot emit
>>>>> instructions for some construct and then that part falls on the
>>>>> normal mechanism; though in some cases the actual machine instructions
>>>
>>> emitted would be the same.
>>>>>
>>>>> So I want to be able to look for some kind of tag in the make check
>>>>> tests.
>>>>>
>>>>> Tia.
>>>>>
>>>>> Reed
>>>>> _______________________________________________
>>>>> LLVM Developers mailing list
>>>>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>>>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>>>
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>
>
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