AVX instructions came along with the new VEX instruction encoding.
Therefore one should compile with option /arch:AVX (or other depending on compiler). Are there any restrictions concerning 32bit or 64bit compilation?
My real question is: Do I get the same performance of AVX compiled for 32 and 64 bit? Or is the VEX encoding only possible for 64 bit, for example? This would lead to transition penalties (SSE to AVX or vice versa) more often.
I could not find a clear answer on this.