On Sat, Jul 30, 2022 at 12:02:02PM +0700, John Naylor wrote: > On Fri, Jul 29, 2022 at 4:34 AM Nathan Bossart <nathandboss...@gmail.com> > wrote: >> * I borrowed USE_SSE2 from one of John Naylor's patches [0]. I'm not > sure >> whether this is committable, > > I'll be the first to say it's not committable and needs some thought. Since > there are several recently proposed patches that take advantage of SSE2, it > seems time for me to open a new thread and get that prerequisite settled. > I'll do that next week.
Awesome. I will help test and review. >> so I would welcome thoughts on the proper >> form. Given the comment says that SSE2 is supported by all x86-64 >> hardware, I'm not seeing why we need the SSE 4.2 checks. Is it not >> enough to check for __x86_64__ and _M_AMD64? > > That's enough for emitting instructions that the target CPU can run, but > says nothing (I think) about the host compiler's ability to understand the > intrinsics and associated headers. The architecture is old enough that > maybe zero compilers in the buildfarm that target AMD64 fail to understand > SSE2 intrinsics, but I hadn't looked into it. The SSE 4.2 intrinsics check > is not necessary, but it was sufficient and already present, so I borrowed > it for the PoC. Got it, makes sense. -- Nathan Bossart Amazon Web Services: https://aws.amazon.com
