John Naylor <johncnaylo...@gmail.com> writes: Hi,
>> Just be curious, what kind of optimization (like what -O2 does) could >> mask this issue? > > In case Andy is asking about "how" rather than "under what > circumstances", my guess is: -O1+ may have just chosen instructions > that also happen to zero-extend, which are common. -O0 doesn't > represent the naive straightforward structure of what the programmer > wrote, it's more like an "exploded" representation suitable for later > optimization passes. That's why it always looks goofy. Thanks for the explaination! >> > Replacing that with _mm512_zextsi128_si512 fixes the problem. > > Here's a patch for testing, which also reverts the previous > workaround. Help welcome, but I still promise to test it in the near > future regardless. I verified the your patch, it works for me. -- Best Regards Andy Fan
