ATLAS.spkg: add Altivec errata support for Linux PPC

[sagetrac-mabshoff]

I was told that this line means that altivec was not detected.
For atlas on linux ppc with altivec, we should use the options
--cflags='-mregnames' -D c -DATL_AVgcc
for configure ( http://math-atlas.sourceforge.net/errata.html#G4gcc ).

With these options, I had "Vector ISA Extension configured as  AltiVec (1,2)".

Best regards,
Bin 

CC: @kiwifb @jpflori

Component: build

Issue created by migration from https://trac.sagemath.org/ticket/3791

[kcrisman]

comment:7

What do you guys think - is this still valid?

[jpflori]

comment:8

Frankly, I'd say we don't care about such systems...
And from the ticket description it just seems that ATLAS won't be optimized on such systems but would still build.

[kiwifb]

comment:9

My own experience is that you need to let ATLAS set its own flags on power7 and probably other ppc(64) arch. It detects and adds altivec/vsx flags appropriately. If you touch CFLAGS you have to make sure to include flags that activate altivec (appropriate -mcpu and -mtune does the trick the CPPFLAGS should be included automatically and failure to include the right flags will result in a compilation failure at some point).

Is this for your project of building a last tiger ppc binary?

[kcrisman]

comment:10

Is this for your project of building a last tiger ppc binary?

No, although that is going fine. This is just me seeing random tickets that possibly could be closed as wontfix/invalid... I can't say whether it would but if you both agree then I say you should do so :)

[kiwifb]

comment:12

I am putting it as "invalid".

[vbraun]

comment:13

You are supposed to change the milestone to "duplicate/invalid/wontfix" then...