[Bug target/64782] New: -mcpu=native should be supported on aarch64

[Bug target/64782] New: -mcpu=native should be supported on aarch64

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64782

            Bug ID: 64782
           Summary: -mcpu=native should be supported on aarch64
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org

Now we have some different CPU supported on AARCH64. We should support
-mcpu=native.  We might need some information from the kernel which is not
supplied yet.

[Bug target/64782] -mcpu=native should be supported on aarch64

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64782

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Depends on|                            |64784

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
-mcpu=native should select the native arch also.

[Bug target/64782] -mcpu=native should be supported on aarch64

[ktkachov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64782

ktkachov at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2015-01-25
                 CC|                            |ktkachov at gcc dot gnu.org
           Assignee|unassigned at gcc dot gnu.org      |ktkachov at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #2 from ktkachov at gcc dot gnu.org ---
I had some work on this for GCC 6

[Bug target/64782] -mcpu=native should be supported on aarch64

[jgreenhalgh at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64782

James Greenhalgh <jgreenhalgh at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jgreenhalgh at gcc dot gnu.org

--- Comment #3 from James Greenhalgh <jgreenhalgh at gcc dot gnu.org> ---
Did the Linux kernel format for /proc/cpuinfo settle down enough that we can
sensibly parse it [1]?

When implementing this support I guess we will want to look at which kernels
are going to be out there in use, and possibly even try to detect the
/proc/cpuinfo format dynamically (Ugh!). Perhaps you just want to mandate a
minimum kernel version, and bail out if you see something older?

[1]: https://lkml.org/lkml/2014/10/24/391

[Bug target/64782] -mcpu=native should be supported on aarch64

[ktkachov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64782

--- Comment #4 from ktkachov at gcc dot gnu.org ---
(In reply to James Greenhalgh from comment #3)
> Did the Linux kernel format for /proc/cpuinfo settle down enough that we can
> sensibly parse it [1]?
> 
> When implementing this support I guess we will want to look at which kernels
> are going to be out there in use, and possibly even try to detect the
> /proc/cpuinfo format dynamically (Ugh!). Perhaps you just want to mandate a
> minimum kernel version, and bail out if you see something older?
> 
> [1]: https://lkml.org/lkml/2014/10/24/391

That's the format in the link that I was thinking of supporting.
The format before the one proposed in the link would work as well, but only for
detecting the native -march or non-big.LITTLE systems.

But since we would want consistent behaviour regardless of kernel version, we
should probably mandate a minimum kernel version for this feature.

[Bug target/64782] -mcpu=native should be supported on aarch64

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64782

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Fixed:
http://cagit1.caveonetworks.com/git/?p=toolchain/gcc.git;a=commit;h=8b81ce60cb7975ad457d58d237d1b533f81ecd7c

--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Fixed:
https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=8b81ce60cb7975ad457d58d237d1b533f81ecd7c

Aka revision 222415 .

[Bug target/64782] -mcpu=native should be supported on aarch64

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64782

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Fixed:
http://cagit1.caveonetworks.com/git/?p=toolchain/gcc.git;a=commit;h=8b81ce60cb7975ad457d58d237d1b533f81ecd7c

--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Fixed:
https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=8b81ce60cb7975ad457d58d237d1b533f81ecd7c

Aka revision 222415 .