On 27/10/15 14:50, H.J. Lu wrote:
> On Tue, Oct 27, 2015 at 7:34 AM, Ramana Radhakrishnan
> <ramana.radhakrish...@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.
