Behaviour of -msse -march=athlon

Ian Lance Taylor iant@google.com
Sun Sep 16 22:25:00 GMT 2007


Ryan Hill <dirtyepic@gentoo.org> writes:

> Are -march options expected to override any relevant options specified
> previously on the command line?

No.  -march should only override previous -march options.  Doing
anything else is complicated and error-prone.

That said, I think it would be reasonable if the compiler issued
warnings about incompatible options after all options have been
parsed.

> It appears in GCC-4.2.0 that SSE movss
> instructions will be generated when for example the following code is compiled
> with -msse -march=athlon:

Don't do that, then.

Ian



More information about the Gcc-help mailing list