[LLVMdev] Scheduling with RAW hazards

[Fraser Cormack]

I have an instruction that takes no operands, and produces two results, 
in two consecutive cycles.

I tried both of the following to my Schedule.td file:

InstrItinData<IIMyInstr,  [InstrStage<2,  [FuncU]>], [1, 2]>,
InstrItinData<IIMyInstr,  [InstrStage<1,  [FuncU]>, InstrStage<1, 
[FuncU]>], [1, 2]>,

 From what I can see in examples, these say that the first operand is 
ready the cycle after issue, and the second is ready 2 cycles after issue.

But when I issue an instruction that uses both results, it does not obey 
this hazard, and is issued the cycle immediately after.  Are there any 
target hooks I need to implement to get this scheduling correctly?

I noticed that my target was using the default HazardRecognizer, which 
is effectively disabled, so I changed it to use the 
ScoreboardHazardRecognizer instead. I'm also still using the 
SelectionDAG scheduler, but will need to change to the MI scheduler at 
some point, to keep up with trunk. Should either of these help?

Thanks,
Fraser

-- 
Fraser Cormack
Compiler Developer
Codeplay Software Ltd
45 York Place, Edinburgh, EH1 3HP
Tel: 0131 466 0503
Fax: 0131 557 6600
Website: http://www.codeplay.com
Twitter: https://twitter.com/codeplaysoft

This email and any attachments may contain confidential and /or privileged information and is for use by the addressee only. If you are not the intended recipient, please notify Codeplay Software Ltd immediately and delete the message from your computer. You may not copy or forward it,or use or disclose its contents to any other person. Any views or other information in this message which do not relate to our business are not authorized by Codeplay software Ltd, nor does this message form part of any contract unless so stated.
As internet communications are capable of data corruption Codeplay Software Ltd does not accept any responsibility for any changes made to this message after it was sent. Please note that Codeplay Software Ltd does not accept any liability or responsibility for viruses and it is your responsibility to scan any attachments.
Company registered in England and Wales, number: 04567874
Registered office: 81 Linkfield Street, Redhill RH1 6BY