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Re: Honnor ix86_accumulate_outgoing_args again

On 11/12/2013 05:26 AM, Jakub Jelinek wrote:
> On Tue, Nov 12, 2013 at 11:05:45AM +0100, Jan Hubicka wrote:
>>> @@ -16576,7 +16576,7 @@ ix86_avx256_split_vector_move_misalign (rtx
>>> op0, rtx op1)
>>>    if (MEM_P (op1))
>>>      {
>>>      {
>>>        rtx r = gen_reg_rtx (mode);
>>>        m = adjust_address (op1, mode, 0);
>>> @@ -16596,7 +16596,7 @@ ix86_avx256_split_vector_move_misalign (rtx
>>> op0, rtx op1)
>>>      }
>>>    else if (MEM_P (op0))
>>>      {
>> I would add explanation comment on those two.
> Looking at
> we are going to have some AMD CPU with AVX2 support soon, the question is
> if it will prefer 256-bit vmovups/vmovupd/vmovdqu or split, but even
> if it will prefer split, the question is if like bdver{1,2,3} it will
> be X86_TUNE_AVX128_OPTIMAL, because if yes, then how 256-bit unaligned
> loads/stores are handled is much less important there.  Ganesh?
>> Shall we also disable argument accumulation for cores? It seems we won't
>> solve the IRA issues, right?
> You mean LRA issues here, right?  If you are starting to use
> no-accumulate-outgoing-args much more often than in the past, I think
> the problem that LRA forces a frame pointer in that case is much more
> important now (or has that been fixed in the mean time?).  Vlad?
I guess it is serious.  So it should fix this for gcc-4.9 in any case. 
I'd say it need 1-2 week of my work.  Right now I am stiil thinking how
to better approach to the implementation of it in LRA.

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