Compiling a gnu program without sse3

Question

I'm compiling an app for a device where the architecture does not support sse beyond sse2, and was wondering is it possible to disable compiling with sse3 instructions from GNU autoconf generated configure scripts? I know you can turn it off in gcc/g++ with mno-sse3 option, but it would be nice if I could turn it off at the configuration level rather than generating a make file and then manually inserting that compiler flag...

Answer 1

Sure. Just set the required flags before calling configure:

$ CFLAGS="-mtune i386" ./configure --enable-this --disable-that ...

You might want to try -march if -mtune does the wrong thing, I haven't tested this lately.

Answer 2

If you are using the more recent versions of gcc, you can simply do -march=native, and the compiler will handle it for you.

Edit: this option was introduced in gcc 4.2.