Re: [PATCH v2 10/42] i386: Rewrite vector shift helper

[Paolo Bonzini]

On 4/25/22 23:33, Richard Henderson wrote:
I do not think it worthwhile to unroll these loops by hand.

Totally agree, as it would also remove most of the uses of 
XMM_ONLY/YMM_ONLY.

I also saw GCC -Warray-bounds complain about

        if (SHIFT >= 1) {
                d->elem[8] = s->elem[8];
        }

though this should probably treated as a GCC bug.

Paolo

If we're that keen on it, it should be written

#pragma GCC unroll 4 << SHIFT
     for (i = 0; i < 4 << SHIFT; ++i) {
         something
     }