[Bug target/17989] New: Add a warning for more than one -march option on command line

[giovannibajo at libero dot it]

It looks like conflicting -march options are not handled correctly. 
Specifically, if you specify both "-march=athlon-xp -march=pentium" on the 
command line, GCC still emits MMX instructions.

I think that the code parsing the -march option in the backend assumes that 
only one option is specified at a time. My suggestion is to emit a warning() if 
more than one option is found on the command line, which is easier to code and 
does not need to be maintained in future.

-- 
           Summary: Add a warning for more than one -march option on command
                    line
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: target
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: giovannibajo at libero dot it
                CC: gcc-bugs at gcc dot gnu dot org
GCC target triplet: x86-*-*


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17989