Bug#268757: gcc-3.4-doc: x86_64 -march=*, -m64 option documentation needs clarification
> Package: gcc-3.4-doc
> Severity: normal
> Generate code for a 32-bit or 64-bit environment. The 32-bit
> environment sets int, long and pointer to 32 bits and generates
> code that runs on any i386 system. The 64-bit environment sets
> int to 32 bits and long and pointer to 64 bits and generates code
> for AMD's x86-64 architecture.
> It is not clear in the above paragraph whether -m64 implies -march=k8
> or what. It probably should not... I am not an expert, that's why I
> went to the manual. Can you please fix it?
GCC never turns something on, which you don't explicitely specify on
the command line. Not sure how you want the documentation be changed.
-m64 turns on the common subset for all x86-64 architectures,
specifying -march=k8 turns on k8/opteron specific features,
-march=nocona turns on some P4/64 Nocona specific features.