Bad option: -march=native on gcc 4.2.1?

[Matt Fago]

On Aug 21, 2007, at 10:19 PM, Ian Lance Taylor wrote:

> Matt Fago <fago@earthlink.net> writes:
>
>> I've built and installed gcc 4.2.1 on a MacBook Pro.
>>
>> This works:
>> /usr/local/bin/gcc -O3 -mtune=native -c Weapon.c
>>
>> This does not:
>> /usr/local/bin/gcc -march=native Weapon.c -c -O3
>> Weapon.c:1: error: bad value (native) for -march= switch
>> Weapon.c:1: error: bad value (native) for -mtune= switch
>>
>>
>> gcc -v yields:
>> Using built-in specs.
>> Target: i386-apple-darwin8.10.1
>> Configured with: ../gcc-4.2.1/configure --disable-checking --enable-
>> languages=c,c++,fortran --with-arch=nocona
>> Thread model: posix
>> gcc version 4.2.1
>>
>> Have I misunderstood something here, or is this some wierd bug?
>
> This is some weird bug.  It should work as you expect.  It does work
> in my testing on GNU/Linux.
>
> Try using the -v option when you compile.  It should show how
> -march=native is transformed when the gcc driver invokes the compiler
> proper.
>
> Ian


I'm not sure this gets anything useful? I usually build gcc on Linux  
as well, so ...


/usr/local/bin/gcc -v -c -O3 -march=native Weapon.c

Using built-in specs.
Target: i386-apple-darwin8.10.1
Configured with: ../gcc-4.2.1/configure --disable-checking --enable- 
languages=c,c++,fortran --with-arch=nocona
Thread model: posix
gcc version 4.2.1
  /usr/local/libexec/gcc/i386-apple-darwin8.10.1/4.2.1/cc1 -quiet -v - 
D__DYNAMIC__ Weapon.c -fPIC -quiet -dumpbase Weapon.c -march=native - 
auxbase Weapon -O3 -version -o /var/tmp//ccSVG0aD.s
ignoring nonexistent directory "NONE/include"
ignoring nonexistent directory "/usr/local/lib/gcc/i386-apple- 
darwin8.10.1/4.2.1/../../../../i386-apple-darwin8.10.1/include"
#include "..." search starts here:
#include <...> search starts here:
  /usr/local/include
  /usr/local/lib/gcc/i386-apple-darwin8.10.1/4.2.1/include
  /usr/include
  /System/Library/Frameworks
  /Library/Frameworks
End of search list.
Weapon.c:1: error: bad value (native) for -march= switch
Weapon.c:1: error: bad value (native) for -mtune= switch
GNU C version 4.2.1 (i386-apple-darwin8.10.1)
         compiled by GNU C version 4.2.1.
GGC heuristics: --param ggc-min-expand=100 --param ggc-min- 
heapsize=131072


  - Matt