Re: [PATCH] elf: Remove -fno-tree-loop-distribute-patterns usage on dl-support

[Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>]

On 09/08/22 16:06, H.J. Lu wrote:
> On Tue, Aug 9, 2022 at 11:48 AM Adhemerval Zanella Netto
> <adhemerval.zanella@linaro.org> wrote:
>>
>>
>>
>> On 09/08/22 15:31, H.J. Lu wrote:
>>> On Tue, Aug 9, 2022 at 5:11 AM Adhemerval Zanella Netto
>>> <adhemerval.zanella@linaro.org> wrote:
>>>>
>>>>
>>>>
>>>> On 08/08/22 19:16, H.J. Lu wrote:
>>>>
>>>>>> --- a/sysdeps/x86_64/multiarch/memset-evex-unaligned-erms.S
>>>>>> +++ b/sysdeps/x86_64/multiarch/memset-evex-unaligned-erms.S
>>>>>> @@ -44,4 +44,7 @@
>>>>>>
>>>>>>  # define USE_LESS_VEC_MASK_STORE       1
>>>>>>  # include "memset-vec-unaligned-erms.S"
>>>>>> +# if !defined NO_MULTIARCH && MINIMUM_X86_ISA_LEVEL >= 4
>>>>>> +strong_alias (__memset_evex_unaligned, __memset_generic)
>>>>>> +# endif
>>>>>>  #endif
>>>>>
>>>>> This will define 2 __memset_generic for -march=x86-64-v4.
>>>>
>>>> Are you sure? Check with a x86_64 build with -march=x86-64-v4 I am seeing:
>>>>
>>>> $ readelf -Ws string/memset*.os | grep -w __memset_generic | wc -l
>>>> 1
>>>>
>>>> And it is indeed provided only by string/memset-evex-unaligned-erms.os.
>>>
>>> You are right.  Since dl-symbol-hacks.h defines memset to an alias,
>>> should it be moved to sysdes/generic and each arch can provide a
>>> suitable alias?
>>
>> The dl-symbol-hacks.h is meant to be used solely by loader code (that's
>> why I have added to elf/), but I don't have a strong preference.
> 
> The default should be no alias.  Only IFUNC targets need to define a
> proper alias.

Alright, although I added the alias on all targets to avoid adding another
hook to specify whether memset is implemented by IFUNC (to enable the
symbol redirection instead of use the default symbol name).  I am not sure
if making arch-specific will simplify the required code here.