Gentoo Archives: gentoo-dev

From: "C Bergström" <cbergstrom@×××××××××.com>
To: "Anthony G. Basile" <gentoo-dev@l.g.o>
Subject: Re: [gentoo-dev] New project: LLVM
Date: Fri, 19 Aug 2016 15:15:39
In Reply to: Re: [gentoo-dev] New project: LLVM by Luca Barbato
1 On Fri, Aug 19, 2016 at 11:01 PM, Luca Barbato <lu_zero@g.o> wrote:
2 > BTW is pathscale ready to be used as system compiler as well?
4 I wish, but no. We have known issues when building grub2, glibc and
5 the Linux kernel at the very least. Someone* did report a long time
6 ago that with their unofficial port, were able to build/boot the
7 NetBSD kernel.
8 (*A community dev we trusted with our sources and was helping us with
9 portability across platforms)
11 The stuff with grub2 may potentially be fixed in the "near" future...
12 the others are more tricky. In general if clang can do it, we have a
13 strong chance as well.
15 As a philosophy - "we" aren't really trying to be the best generic
16 compiler in the world. We aim more on optimizing as much for known
17 targets. So if by system you mean, a compiler that would produce an
18 "OS" which only runs on a single class of hardware, then yeah it could
19 work at some point in the future. Specifically, on x86 we default on
20 host CPU optimizations. So on newer Intel hardware it's easy to get a
21 binary that won't run on AMD or older 64bit Intel.
23 More recently on ARMv8 - we turn on processor specific tuning. So
24 while it may "run", the difference between APM's mustang and Cavium
25 ThunderX is pretty big and running binaries intended for A and ran on
26 B would certainly take a hit.. (this is just the tip of the iceberg)
28 For general scalar OS code it isn't likely to matter... the real
29 impact being like 1-10% difference (being very general.. it could be
30 less or more in the real world..)
32 For HPC codes or anything where you get loops or computationally
33 complex - the gloves are off and I could see big differences... (again
34 being general and maybe a bit dramatic for fun)


Subject Author
Re: [gentoo-dev] New project: LLVM Luca Barbato <lu_zero@g.o>
Re: [gentoo-dev] New project: LLVM james <garftd@×××××××.net>