[LLVMdev] Pat operands matching example in ppc

[Anitha B Gollamudi]

On 7 April 2013 14:54, Sam Parker <S.Parker3 at lboro.ac.uk> wrote:
> Hi Anitha,
>
> memri is just describing that the address contains two components, an
> immediate and a register, and how to handle them in the instruction printer.
> The STWU expects a memri operand, and that is what is passed from the Pat.
>

My confusion is how operands of STWU from "Pat pre_store" get matched
with those of memri. It is defined with operand types as:

let MIOperandInfo = (ops dispRI:$imm, ptr_rc_nor0:$reg);

while Pat is defined as:

def : Pat<(pre_store i32:$rS, iPTR:$ptrreg, iaddroff:$ptroff),
              (STWU $rS, iaddroff:$ptroff, $ptrreg)>;


So now how iPTR:$ptrreg and iaddroff:$ptroff get matched with
ptr_rc_nor0:$reg and dispRI:$imm respectively? I mean the types are
not exactly matching. Probably something is amiss in my understanding.

-Anitha

>
> On 07/04/2013 10:19, Anitha B Gollamudi wrote:
>
> Hi,
>
>
> How do "Pat" operands get matched? I am trying to follow the example given
> in http://llvm.org/docs/CodeGenerator.html#selectiondag-process
>
> In the latest trunk of ppcintrinfo.td following pattern is defined:
>
> def : Pat<(pre_store i32:$rS, iPTR:$ptrreg, iaddroff:$ptroff),
>               (STWU $rS, iaddroff:$ptroff, $ptrreg)>;
>
> I understand that input operand list i.e. ins of stwu should get matched
> with the given pre_store. But I am confused as to how  "ptroff" and "ptrreg"
> get matched with "memri" used in STWU?
>
>
> For reference[1] memri is defined as:
>
> def memri :Operand<iPTR> {
>
> let PrintMethod = "printMemRegImm";
>
> let MIOperandInfo = (ops dispRI:$imm,  ptr_rc_nor0:$reg);
>
> let EncoderMethod = "getMemRIEncoding";
> }
>
> [1]
> https://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/PPCInstrInfo.td?view=markup
> --
>  Anitha
>
>
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--
 Anitha