"Zuxy Meng" <zuxy.meng@xxxxxxxxx> writes: > I mean what will gcc do if no '--with-cpu' '--with-arch' '--with-tune' etc > are given during configuration. Specifically for x86, when neither march nor > mtune is given, will gcc merely treat it as march=i386 mtune=i386? You need to say precisely how gcc was configured, or you need to tell us the "Target:" line printed by gcc -v. If the target is, e.g., i386-pc-linux-gnu, and none of the options you mentioned was specified, then older versions of gcc will tune for the i386, and recent versions of gcc will tune as though gcc were configured with --with-tune=generic. Ian
