* Paul Richards via Gcc-help: > I ask, because the documentation doesn't make it clear what happens, > but at the same time using "-march" with x86-64 psABI levels > apparently invokes generic tuning and it would be weird if generic > tuning under "-march=x86-64-v4" wasn't different than generic tuning > under "-march=x86-64". The tuning defaults for -march=x86-64-v* need some discussion. For example, for -march=x86-64-v4, maybe GCC should tune for 256-bit vector widths. For both -march=x86-64-v3 and -march=x86-64-v4, there is some tuning for FMA that could be applied. I'm sure there are other examples. Thanks, Florian
