[LLVMdev] Instr Description Problem of MCore Backend

Anton Korobeynikov anton at korobeynikov.info
Thu Jun 23 06:51:09 PDT 2011


Hello

> Finally, I don't know how to describe following instructions in
> MCoreInstrInfo.td, because of its variable ins/outs. Or what other files
> should I use to finish this description?
Do you need the isel support for them? If yes, then you should custom
isel them. iirc ARM and SystemZ backends have similar instructions,
while only the first one supports full isel for them. In short: you
should recognize the consecutive loads / stores and turn them into
load/store multiple.

If you just need the have assembler support, then you don't need to
specify the exact operands there (for "Q" instructions), since they
are fixed. Just provide the list of used / clobbered instructions.

-- 
With best regards, Anton Korobeynikov
Faculty of Mathematics and Mechanics, Saint Petersburg State University



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