[Bug libstdc++/114417] std::experimental::simd is not a POD (by ABI definitions) and is always passed by reference instead of by value

[lee.imple at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114417

--- Comment #7 from Imple Lee <lee.imple at gmail dot com> ---
I tried to dig into the source code and it seems like it was designed to be
"passed via the stack". Not sure whether this was specified by the
specification (did not find relevant requirements, but I am not quite familiar
with that) or just an implementation choice.

In GCC git tree [libstdc++-v3/include/experimental/bits/simd_fixed_size.h, line
27](https://gcc.gnu.org/git?p=gcc.git;a=blob;f=libstdc%2B%2B-v3/include/experimental/bits/simd_fixed_size.h;h=408855212979cc32699db0805079ac74f495a8fa;hb=HEAD#l27):

...
  * The fixed_size ABI gives the following guarantees:
  *  - simd objects are passed via the stack
...