Taking advantage of SSE and other CPU extensions

Question

Theres are couple of places in my code base where the same operation is repeated a very large number of times for a large data set. In some cases it\'s taking a considerable tim

Answer 1

In answer to your comment:

So effectively, as long as I don't try to actually execute code containing unsupported instructions I'm fine, and I could get away with an "if(see2Supported){...}else{...}" type switch?

Depends. It's fine for SSE instructions to exist in the binary as long as they're not executed. The CPU has no problem with that.

However, if you enable SSE support in the compiler, it will most likely swap a number of "normal" instructions for their SSE equivalents (scalar floating-point ops, for example), so even chunks of your regular non-SSE code will blow up on a CPU that doesn't support it.

So what you'll have to do is most likely compile on or two files separately, with SSE enabled, and let them contain all your SSE routines. Then link that with the rest of the app, which is compiled without SSE support.