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Re: [PATCH] PR target/68991: Add vector_memory_operand and "Bm" constraint


On Tue, Jan 5, 2016 at 7:58 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Tue, Jan 5, 2016 at 4:32 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> On Tue, Jan 5, 2016 at 12:11 AM, Jakub Jelinek <jakub@redhat.com> wrote:
>>> On Mon, Jan 04, 2016 at 03:25:48PM -0800, H.J. Lu wrote:
>>>> LRA is fine.  I should use
>>>>
>>>> (define_memory_constraint "Bm"
>>>>   "@internal Vector memory operand."
>>>>   (match_operand 0 "vector_memory_operand"))
>>>>
>>>> instead of
>>>>
>>>> (define_constraint "Bm"
>>>>   "@internal Vector memory operand."
>>>>   (match_operand 0 "vector_memory_operand"))
>>>
>>> I don't think so.  At least the documentation says that
>>> define_memory_constraint is for MEM constraints where if they are not
>>> satisfied they can be made to satisfy by forcing the address into a
>>> register.  But that is not the case here, if a MEM is misaligned, no
>>> equivalent changes to the XEXP (mem, 0) will make it aligned.
>>>
>>
>> You are right and *mov<mode>_internal must use the 'm' constraint
>> so that LRA won't keep generating the same reload for
>>
>> (insn 353 322 323 8 (set (reg:V4SF 192)
>>         (reg:V4SF 201 [192])) 1226 {*movv4sf_internal}
>>      (nil))
>>
>> until
>>
>> x.i: In function \u2018foo\u2019:
>> x.i:29:1: internal compiler error: Max. number of generated reload
>> insns per insn is achieved (90)
>>
>>  }
>>  ^
>>
>> 0xc0d635 lra_constraints(bool)
>> /export/gnu/import/git/sources/gcc/gcc/lra-constraints.c:4336
>> 0xbf9854 lra(_IO_FILE*)
>> /export/gnu/import/git/sources/gcc/gcc/lra.c:2277
>> 0xba6489 do_reload
>> /export/gnu/import/git/sources/gcc/gcc/ira.c:5385
>> 0xba683c execute
>> /export/gnu/import/git/sources/gcc/gcc/ira.c:5556
>>
>>
>
> Here are the updated patches.  I didn't change SSE
> *mov<mode>_internal.  Tested on x86-64.  OK for
> trunk?

It is hard to determine the changed patterns - can you confirm that
only patterns where ssememalign=0 are changed?

Uros.


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