Re: [PATCH] xtensa: fix access to the last pseudo register

[Max Filippov <jcmvbkbc@gmail.com>]

On Fri, May 29, 2015 at 12:40 PM, Pedro Alves <palves@redhat.com> wrote:
> On 05/27/2015 11:55 AM, Max Filippov wrote:
>> On Wed, May 27, 2015 at 1:16 PM, Pedro Alves <palves@redhat.com> wrote:
>>> On 05/18/2015 12:12 AM, Max Filippov wrote:
>>>> Currently access to the last pseudo register is aliased to a1. This is
>>>> done by little snippets in the beginning of xtensa_pseudo_register_read
>>>> and xtensa_pseudo_register_write that used to do such aliasing for FP
>>>> register since bdb4c075a29dd086f0868b394b488b1c94666be6, but then
>>>> FP_ALIAS was expanded into gdbarch_num_regs (current_gdbarch) +
>>>> gdbarch_num_pseudo_regs (current_gdbarch) (one register past the last
>>>> pseudo register) in 304fe2552d6e0821e8fdb7575f8e7ba6607a076d, which
>>>> then was changed to the last pseudo register in
>>>> 94a0e877111421d300d26b858bd3a0a27078d1e8.
>>>
>>> IIUC, the original intention was for FP to alias a1, and then through
>>> that series of patches (part of old current_gdbarch elimination)
>>> we ended up aliasing the wrong register.  Instead of fixing the
>>> aliasing, you're just removing it altogether.  Correct?
>>
>> I'm removing that aliasing to expose the last pseudoregister.
>> After that patch fp pseudo register still exists and it is a read only alias
>> for a1. I don't think that's right, because normally frame pointer is a7 or
>> a15, depending on ABI, but that's definitely a separate question.
>
> Ah, ok.  FAOD, patch is still OK.  :-)

Thanks! Checked in.

-- Max