Re: [extcontact] Re: PPC64: gcc currently compiles for power4 by default, causing glibc's sqrtf to fail on e6500

[Mathieu Malaterre <malat@debian.org>]

Hi all,

On Fri, Feb 9, 2018 at 1:12 PM, Luuk van Dijk <lvd@daedalean.ai> wrote:
> I apologize for the 'reply in 48 hours' spam my extcontacts mailinglist
> caused for any of you that replied here.  I asked bas to keep us posted but
> i didn't realize it would send this out.  I switched it off.
>
> thanks for all your hard work.
>
> /Luuk
>
> On Fri, Feb 9, 2018 at 12:56 PM Bas Vermeulen <bas@daedalean.ai> wrote:
>>
>> diff of gcc -dM -E - without and with the patch applied:
>>
>> --- gcc-default 2018-01-28 18:06:14.116000000 +0000
>> +++ gcc-powerpc64 2018-01-28 18:03:06.572000000 +0000
>> @@ -34,7 +34,6 @@
>>  #define __FLT64_DECIMAL_DIG__ 17
>>  #define __GCC_ATOMIC_CHAR32_T_LOCK_FREE 2
>>  #define pixel pixel
>> -#define _ARCH_PPCSQ 1
>>  #define bool bool
>>  #define __UINT_FAST64_MAX__ 0xffffffffffffffffUL
>>  #define __SIG_ATOMIC_TYPE__ int
>> @@ -78,7 +77,6 @@
>>  #define __USER_LABEL_PREFIX__
>>  #define __STDC_HOSTED__ 1
>>  #define __LDBL_HAS_INFINITY__ 1
>> -#define _ARCH_PWR4 1
>>  #define __builtin_vsx_xvmaddmsp __builtin_vsx_xvmaddsp
>>  #define __CMODEL_MEDIUM__ 1
>>  #define __FLT32_DIG__ 6
>>
>> gcc -Q --help=target (default vs with the patch applied):
>>
>> --- gcc-Q-default 2018-01-28 18:08:29.232000000 +0000
>> +++ gcc-Q-powerpc64 2018-01-28 18:07:39.984000000 +0000
>> @@ -35,7 +35,7 @@
>>    -mcmodel=                    medium
>>    -mcmpb                      [disabled]
>>    -mcompat-align-parm          [disabled]
>> -  -mcpu=                      [default]
>> +  -mcpu=                      powerpc64
>>    -mcrypto                    [disabled]
>>    -mdebug=
>>    -mdirect-move                [disabled]
>> @@ -70,7 +70,7 @@
>>    -mlong-double-<n>            128
>>    -mlongcall                  [disabled]
>>    -mlra                        [enabled]
>> -  -mmfcrf                      [enabled]
>> +  -mmfcrf                      [disabled]
>>    -mmfpgpr                    [disabled]
>>    -mminimal-toc                [disabled]
>>    -mmodulo                    [disabled]
>> @@ -89,7 +89,7 @@
>>    -mpointers-to-nested-functions [enabled]
>>    -mpopcntb                    [disabled]
>>    -mpopcntd                    [disabled]
>> -  -mpower8-fusion              [enabled]
>> +  -mpower8-fusion              [disabled]
>>    -mpower8-fusion-sign        [disabled]
>>    -mpower8-vector              [disabled]
>>    -mpower9-dform              [enabled]
>> @@ -101,9 +101,9 @@
>>    -mpower9-vector              [disabled]
>>    -mpowerpc
>>    -mpowerpc-gfxopt            [enabled]
>> -  -mpowerpc-gpopt              [enabled]
>> +  -mpowerpc-gpopt              [disabled]
>>    -mpowerpc64                  [enabled]
>> -  -mprioritize-restricted-insns= 1
>> +  -mprioritize-restricted-insns= 0
>>    -mprofile-kernel            [disabled]
>>    -mprototype                  [disabled]
>>    -mquad-memory                [disabled]
>> @@ -145,7 +145,7 @@
>>    -mtoc                        [disabled]
>>    -mtoc-fusion                [disabled]
>>    -mtraceback=                [default]
>> -  -mtune=                      [default]
>> +  -mtune=                      powerpc64
>>    -muclibc                    [disabled]
>>    -mupdate                    [enabled]
>>    -mupper-regs                [enabled]

The diff looks a bit odd to me, I do not understand why we would be
moving away from the default mtune. Anyway you have my vote. I know
Adrian gets sometime inspiration from fedora team, maybe time to reach
a consensus with them also. IBM seems to be going toward ppc64el
anyway, so I believe that should not affect too many people.

2cts,
-M