Re: [PATCH, aarch64] Add prefetch support

[Andrew Pinski <pinskia at gmail dot com>]

On Tue, Nov 11, 2014 at 6:47 AM, Marcus Shawcroft
<marcus.shawcroft@gmail.com> wrote:
> On 30 October 2014 08:54, Gopalasubramanian, Ganesh
> <Ganesh.Gopalasubramanian@amd.com> wrote:
>
>> 2014-10-30  Ganesh Gopalasubramanian <Ganesh.Gopalasubramanian@amd.com>
>
> Check the whitespace in your ChangeLog line.
>
>>         * config/arm/types.md (define_attr "type"): Add prefetch.
>
> The existing schedulers use 'load1'.  We can of course split that into
> two introducing "prefetch" and update all of the existing schedulers
> to reflect the change.  However I suggest we do that as a separate
> activity when someone actually needs the distinction, note this change
> will require updating the schedulers for both ARM and AArch64 backends
> not just those relevant to AArch64.  For this prefetch patch I suggest
> we go with the existing "load1".

I will need this change for ThunderX schedule.  The Pref instruction
is single issued while load1 can be dual issued.

Thanks,
Andrew

>
> The inline patch has been munged by your mailer, I tried applying the
> patch to my tree but it is full of  escape sequences.  Can you either
> fix your mailer or submit patches as attachments?
>
>> diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
>> index 74b554e..12a3f170 100644
>> --- a/gcc/config/aarch64/aarch64.md
>> +++ b/gcc/config/aarch64/aarch64.md
>> @@ -320,6 +320,38 @@
>>    [(set_attr "type" "no_insn")]
>> )
>>
>> +
>> +(define_insn "prefetch"
>> +  [(prefetch (match_operand:DI 0 "address_operand" "r")
>> +            (match_operand:QI 1 "const_int_operand" "")
>> +            (match_operand:QI 2 "const_int_operand" ""))]
>> +  ""
>
>> +  "*
>> +{
>
> Use {} instead of "*{, then all of the extra quoting in the C below goes away.
>
>> +  const char * pftype[2][10]
>> +    = { {\"PLDL1STRM\", \"PLDL3KEEP\", \"PLDL2KEEP\", \"PLDL1KEEP\"},
>> +       {\"PSTL1STRM\", \"PSTL3KEEP\", \"PSTL2KEEP\", \"PSTL1KEEP\"},
>> +      };
>> +
>> +  int locality = INTVAL (operands[2]);
>> +  char pattern[100];
>> +
>> +  gcc_assert (IN_RANGE (locality, 0, 3));
>> +
>> +  strcpy (pattern, \"prfm\\t\");
>> +  strcat (pattern, (const char*)pftype[INTVAL(operands[1])][locality]);
>> +  strcat (pattern, \", %a0\");
>
> Use sprintf() rather that multiple calls to cpy and cat.  I suspect
> the cast in front of pftype is superflous?
>
>> +
>> +  output_asm_insn (pattern,
>> +                   operands);
>
> Unnecessary line break.
>
> Cheers
> /Marcus