Re: [PATCH] rs6000: Fix ICE of vect cost related to V1TI [PR102767]

["Kewen.Lin" <linkw@linux.ibm.com>]

on 2021/10/28 上午9:43, David Edelsohn wrote:
> On Wed, Oct 27, 2021 at 9:30 PM Kewen.Lin <linkw@linux.ibm.com> wrote:
>>
>> Hi David,
>>
>> Thanks for the review!
>>
>> on 2021/10/27 下午9:12, David Edelsohn wrote:
>>> On Sun, Oct 24, 2021 at 11:04 PM Kewen.Lin <linkw@linux.ibm.com> wrote:
>>>>
>>>> Hi,
>>>>
>>>> As PR102767 shows, the commit r12-3482 exposed one ICE in function
>>>> rs6000_builtin_vectorization_cost.  We claims V1TI supports movmisalign
>>>> on rs6000 (See define_expand "movmisalign<mode>"), so it return true in
>>>> rs6000_builtin_support_vector_misalignment for misalign 8.  Later in
>>>> the cost querying rs6000_builtin_vectorization_cost, we don't have
>>>> the arms to handle the V1TI input under (TARGET_VSX &&
>>>> TARGET_ALLOW_MOVMISALIGN).
>>>>
>>>> The proposed fix is to add the consideration for V1TI, simply make it
>>>> as the cost for doubleword which is apparently bigger than the cost of
>>>> scalar, won't have the vectorization to happen, just to keep consistency
>>>> and avoid ICE.  Another thought is to not support movmisalign for V1TI,
>>>> but it sounds like a bad idea since it doesn't match the reality.
>>>>
>>>> Bootstrapped and regtested on powerpc64le-linux-gnu P9 and
>>>> powerpc64-linux-gnu P8.
>>>>
>>>> Is it ok for trunk?
>>>>
>>>> BR,
>>>> Kewen
>>>> -----
>>>> gcc/ChangeLog:
>>>>
>>>>         PR target/102767
>>>>         * config/rs6000/rs6000.c (rs6000_builtin_vectorization_cost): Consider
>>>>         V1T1 mode for unaligned load and store.
>>>>
>>>> gcc/testsuite/ChangeLog:
>>>>
>>>>         PR target/102767
>>>>         * gcc.target/powerpc/ppc-fortran/pr102767.f90: New file.
>>>>
>>>> diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
>>>> index b7ea1483da5..73d3e06c3fc 100644
>>>> --- a/gcc/config/rs6000/rs6000.c
>>>> +++ b/gcc/config/rs6000/rs6000.c
>>>> @@ -5145,7 +5145,8 @@ rs6000_builtin_vectorization_cost (enum vect_cost_for_stmt type_of_cost,
>>>>         if (TARGET_VSX && TARGET_ALLOW_MOVMISALIGN)
>>>>           {
>>>>             elements = TYPE_VECTOR_SUBPARTS (vectype);
>>>> -           if (elements == 2)
>>>> +           /* See PR102767, consider V1TI to keep consistency.  */
>>>> +           if (elements == 2 || elements == 1)
>>>>               /* Double word aligned.  */
>>>>               return 4;
>>>>
>>>> @@ -5184,10 +5185,11 @@ rs6000_builtin_vectorization_cost (enum vect_cost_for_stmt type_of_cost,
>>>>
>>>>          if (TARGET_VSX && TARGET_ALLOW_MOVMISALIGN)
>>>>            {
>>>> -            elements = TYPE_VECTOR_SUBPARTS (vectype);
>>>> -            if (elements == 2)
>>>> -              /* Double word aligned.  */
>>>> -              return 2;
>>>> +           elements = TYPE_VECTOR_SUBPARTS (vectype);
>>>> +           /* See PR102767, consider V1TI to keep consistency.  */
>>>> +           if (elements == 2 || elements == 1)
>>>> +             /* Double word aligned.  */
>>>> +             return 2;
>>>
>>> This section of the patch incorrectly changes the indentation.  Please
>>> use the correct indentation.
>>>
>>
>> The indentation change is intentional since the original identation is
>> wrong (more than 8 spaces leading the lines), there are more wrong
>> identation lines above the first changed line, but I thought it seems a
>> bad idea to fix them too when they are unrelated to what this patch
>> wants to fix, so I left them alone.
>>
>> With the above clarification, may I push this patch without any updates
>> for the mentioned indentation issue?
> 
> If you correct the indentation, you should adjust it for the entire
> block, not just the lines that you change.  If you want to fix the
> entire block to TAB+spaces as well, okay.  You didn't mention that you
> were fixing the indentation in the explanation of the patch.
> 

Sorry for not mentioning that.  Got it, I'll reformat the entire block then,
also with additional notes in the commit log.

Thanks again.

BR,
Kewen

> Thank, David
> 
>>
>>>>
>>>>              if (elements == 4)
>>>>                {
>>>> diff --git a/gcc/testsuite/gcc.target/powerpc/ppc-fortran/pr102767.f90 b/gcc/testsuite/gcc.target/powerpc/ppc-fortran/pr102767.f90
>>>> new file mode 100644
>>>> index 00000000000..a4122482989
>>>> --- /dev/null
>>>> +++ b/gcc/testsuite/gcc.target/powerpc/ppc-fortran/pr102767.f90
>>>> @@ -0,0 +1,21 @@
>>>> +! { dg-require-effective-target powerpc_vsx_ok }
>>>> +! { dg-options "-mvsx -O2 -ftree-vectorize -mno-efficient-unaligned-vsx" }
>>>> +
>>>> +INTERFACE
>>>> +  FUNCTION elemental_mult (a, b, c)
>>>> +    type(*), DIMENSION(..) :: a, b, c
>>>> +  END
>>>> +END INTERFACE
>>>> +
>>>> +allocatable  z
>>>> +integer, dimension(2,2) :: a, b
>>>> +call test_CFI_address
>>>> +contains
>>>> +  subroutine test_CFI_address
>>>> +    if (elemental_mult (z, x, y) .ne. 0) stop
>>>> +    a = reshape ([4,3,2,1], [2,2])
>>>> +    b = reshape ([2,3,4,5], [2,2])
>>>> +    if (elemental_mult (i, a, b) .ne. 0) stop
>>>> +  end
>>>> +end
>>>> +
>>>>
>>>
>>> The patch is okay with the indentation correction.
>>>
>>> Thanks, David
>>>
>>
>> Thanks!
>>
>> BR,
>> Kewen