Is UBSan supposed to produce a finding for _mm_load_sd and _mm_store_sd

[Jeffrey Walton]

I have some code that loads a 64-bit integer into a XMM register. It
loads the integer from a byte array:

    byte v[8] = ...
    __m128i t = _mm_castpd_si128(
        _mm_load_sd((const double *)(v)));

It is producing a finding for an unaligned load. I get similar
findings for _mm_load_sd, _mm_store_sd and _mm_loaddup_pd.

According to the Intel Intrinsics Guide (e.g., _mm_load_sd):

    Load a double-precision (64-bit) floating-point element from memory
    into the lower of dst, and zero the upper element. mem_addr does
    not need to be aligned on any particular boundary.

Should GCC be producing a finding in this case? Is there a way to work
around it without an extra memcpy?

A similar Clang issue is at http://bugs.llvm.org/show_bug.cgi?id=20670 .

Thanks in advance,

Jeff