title: Using xmm parameter in AVX intrinsics
body: <p>Is it possible to use xmm register parameter with AVX intrinsics function (<code>_mm256_**_**</code>)?</p>
  
  <p>My code require the usage of vecter integer operation (for load and storing data) along with vector floating point operation. The integer code is written with SSE2 intrinsics to be compatible with older CPU, while floating point is written with AVX to improve speed (there is also SSE code branch, so do not suggest this).</p>
  
  <p>Currently, except for using compiler flag to automatically convert all SSE instructions to VEX-encoded version, are there any way using intrinsics function (i.e. no inline/external assembly) to force the use of VEX-encoded instruction on XMM register?</p>
  
  <p>Note: I tried <code>_mm256_castsi128_si256()</code>, and this generates instruction with ymm operand.</p>