Why isn't there a format that like fat binaries will allow an executable to run with different instruction sets but on the same architecture?

It would make it possible to have optimized binaries for several p开发者_C百科rocessors.

If done right it wouldn't even need to duplicate much data.

If I get the question right, you're asking a format with builds optimized for different CPU's of the same family.

The downside of this is that there is need for more testing. You're not likely to find anything, but it's so embarresing if your final build mistakenly contains the wrong version of the code.

The gains may also not be that great: usually compilers optimize such that they avoid known performance issues with common CPU architectures. You may argue that your software will benefit from SSE instructions on new hardware, but if your application is so demanding that it needs SSE instructions even on recent hardware, your software will be close to unusable on older CPUs.