Re: PING: [PATCH] PR target/67215: -fno-plt needs improvements for x86

[Ramana Radhakrishnan <ramana.radhakrishnan@foss.arm.com>]

On 27/10/15 14:50, H.J. Lu wrote:
> On Tue, Oct 27, 2015 at 7:34 AM, Ramana Radhakrishnan
> <ramana.radhakrishnan@foss.arm.com> wrote:
>>
>>>
>>> OK, then it's fairly x86-64 specific optimization, because we can't do "call *mem" in
>>> aarch64 and some other targets.
>>
>> It is a fairly x86_64 specific optimization and doesn't apply to AArch64.
>>
>> The question really is what impact does removing the generic code handling have on aarch64 - is it a no-op or not for the existing -fno-plt implementation in the AArch64 backend ? The only case that is of interest is the bit below in calls.c and it looks like that may well be redundant with the logic in the backend already, but I have not done the full analysis to convince myself that the code in the backend is sufficient.
>>
>> -  && (!flag_plt
>> -              || lookup_attribute ("noplt", DECL_ATTRIBUTES (fndecl_or_type)))
>> -          && !targetm.binds_local_p (fndecl_or_type))
>>
> 
> -fno-plt is a backend specific optimization and should be handled
> in backend.
> 

HJ, Thanks for committing the change even when we were discussing the change - As I suspected the handling in the backend isn't sufficient, the call expanders need to handle this case in the AArch64 backend. Minimally tested -

Ok if no regressions on aarch64-none-elf?

regards
Ramana

* config/aarch64/aarch64.md (call, call_value): Handle noplt.