[llvm] r206496 - Improve ARM64 vector creation

[Tim Northover]

Hi Louis,

> +; RUN: llc -march=arm64 -mcpu=generic < %s | FileCheck %s>

Just noticed a bot complain about this: it needs
"-arm64-neon-syntax=apple" to work.

Apologies if you saw this on IRC. Didn't mean to harangue you, just
save you some investigation effort.

Cheers.

Tim.