pextrq + movq crosses register files twice, which is not efficient.
Optimize this by:
- checking if lane 0, do nothing if dst == src (macro-assembler helper)
- use vmovhlps on AVX, with src as the operands to avoid false
dependency on dst
- use movhlps otherwise, this is shorter than shufpd, and faster on
older system
Change-Id: I3486d87224c048b3229c2f92359b8b8e6d5fd025
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2589056
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Reviewed-by: Bill Budge <bbudge@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71751}
6cb61e63bb