On 12/29/23 21:20, Konstantin Belousov wrote:
On Fri, Dec 29, 2023 at 09:12:35PM +0100, Harry Schmalzbauer wrote:
On 12/29/23 18:00, Dimitry Andric wrote:
On 29 Dec 2023, at 11:14, Harry Schmalzbauer <free...@omnilan.de> wrote:
at least since 14-release, I can't compile base/ports with CPUTYPE post
nehalem. Any '-march' declaring AVX(*) capability leads to SIGILLing binaries
with default -O2 CFLAGS.
..
If I compile without CFLAGS -O2 ("CFLAGS= -pipe"), -march=skylake-avx512 the
binary doens't crash with SIGILL.
Is CPUTYPE supposed to stay untouched these days?
Obviously not, but are you sure your target CPU is correct? If it is not, the
compiler may insert unsupported instructions.
Ho Dimitry, thanks for your attention!
I have to admit that I know much too less about contemporary compilers and
CPUs likewise, but target CPU matches -march ;-)
I nailed it down to AVX instructions. Starting with 'sandybridge', Intel
CPUs provide avx instruction units, and starting with CPUTYPE?=sandybridge,
binaries crash on stable/14 (and late 14-current) on the corresponding
machines. But only in combination with CFLAGS -O2!
In any case, for the above gdb session, try the command "disassemble" to see
which particular instruction it crashed on. That may give more information.
Thanks for the hint!
This came out:
Program terminated with signal SIGILL, Illegal instruction.
Privileged opcode.
#0 0x000000000041e040 in init_yank ()
(gdb) disassemble
Dump of assembler code for function init_yank:
0x000000000041e030 <+0>: push %rbp
0x000000000041e031 <+1>: mov %rsp,%rbp
0x000000000041e034 <+4>: vpxor %xmm0,%xmm0,%xmm0
0x000000000041e038 <+8>: vmovdqa -0x202c10(%rip),%xmm1 #
0x21b430
=> 0x000000000041e040 <+16>: kxnorw %k0,%k0,%k1
This is AVX512 instruction (some of it subset, probably F), not AVX.
..
Intel(R) Xeon(R) CPU E3-1275 v6 @ 3.80GHz (3800.00-MHz K8-class CPU)
My bad, sorry.
Confused machines. This indeed was wrong target CPU, stupid me.
Previously I tested tih CPUTYPE?=haswell, which editors/vim survives
currently.
Will run a base build with CPUTYPE?=haswell over the weekend and report
back.
Sorry for the noise so far...
-harry
