[Bug target/30336] New: -mtune=native is wrong when not built with gcc

[Bug target/30336] New: -mtune=native is wrong when not built with gcc

[hjl at lucon dot org]

When gcc isn't built with gcc, we get

  if (arch)
    {   
      /* FIXME: i386 is wrong for 64bit compiler.  How can we tell if
         we are generating 64bit or 32bit code?  */
      cpu = "i386";
    }   
  else
    cpu = "generic";

It is suggested to use size of (void *):

http://gcc.gnu.org/ml/gcc/2006-12/msg00651.html

However, it only checks the pointer size  of the compiler which  is used to
build
gcc, not the pointer size of the gcc.


-- 
           Summary: -mtune=native is wrong when not built with gcc
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: target
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: hjl at lucon dot org
GCC target triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30336

[Bug target/30336] -mtune=native is wrong when not built with gcc

[pinskia at gcc dot gnu dot org]

------- Comment #1 from pinskia at gcc dot gnu dot org  2006-12-31 01:22 -------
I always thought cross compilers needed GCC to compile anyways so I don't see
why this is a bug?
If you mean while bootstrapping and someone uses --with-tune=native, I still
don't see why this is an issue as that would be a bug with their use of options
while configuring.

Can you better explain what exactly what is wrong with this instead of just
saying it is broken?


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30336

[Bug target/30336] -mtune=native is wrong when not built with gcc

[hjl at lucon dot org]

------- Comment #2 from hjl at lucon dot org  2006-12-31 09:25 -------
It isn't really about cross compiler. It is about the compiler which is used to
compile gcc. Since we don't know if the compiler can handle cpuid asm statement
like gcc, when we are building gcc, there is no way for us to call cpuid.

BTW, it is quite rare not to use gcc to build gcc, considering bootstrap.
The only case I can think of is when we use another compiler to build
canadian cross compiler where target == host and host != build.


-- 

hjl at lucon dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2006-12-31 09:25:58
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30336

[Bug target/30336] -mtune=native is wrong when not built with gcc

[pinskia at gcc dot gnu dot org]

------- Comment #3 from pinskia at gcc dot gnu dot org  2006-12-31 10:26 -------
(In reply to comment #2)
> BTW, it is quite rare not to use gcc to build gcc, considering bootstrap.
> The only case I can think of is when we use another compiler to build
> canadian cross compiler where target == host and host != build.

But I still say any kind of crosses are not allowed to be built with a non GCC.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30336

[Bug target/30336] -mtune=native is wrong when not built with gcc

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=30336

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|NEW                         |RESOLVED
   Target Milestone|---                         |4.5.0

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
This was fixed with r0-93833 where we ignore now -march=native and/or
-mtune=native if not compiled with GCC, There were more fixes later on what
macro gets tested too.