Bug#1084954: Fwd: llvm-toolchain-*: assembly code seems to depend on build cpu capabilities

[Holger Levsen]

Hi Paul,

On Sun, Apr 06, 2025 at 04:00:41PM +0200, Paul Gevers wrote:
> I assume it is still valid to do this. At least without information this bug
> might remain RC and I understand is hardly actionable. I guess you only need
> to inspect the two nodes that were used for one of the failing
> llvm-toolchain-18|19 runs e.g. ionos1-amd64 vs ionos15-amd64

holger at ionos15-amd64:~ $ /lib/x86_64-linux-gnu/ld-linux-x86-64.so.2 --help
Usage: /lib/x86_64-linux-gnu/ld-linux-x86-64.so.2 [OPTION]... EXECUTABLE-FILE [ARGS-FOR-PROGRAM...]
You have invoked 'ld.so', the program interpreter for dynamically-linked
ELF programs.  Usually, the program interpreter is invoked automatically
when a dynamically-linked executable is started.

[...]

This program interpreter self-identifies as: /lib64/ld-linux-x86-64.so.2

Shared library search path:
  (libraries located via /etc/ld.so.cache)
  /lib/x86_64-linux-gnu (system search path)
  /usr/lib/x86_64-linux-gnu (system search path)
  /lib (system search path)
  /usr/lib (system search path)

Subdirectories of glibc-hwcaps directories, in priority order:
  x86-64-v4
  x86-64-v3 (supported, searched)
  x86-64-v2 (supported, searched)

Legacy HWCAP subdirectories under library search path directories:
  haswell (AT_PLATFORM; supported, searched)
  tls (supported, searched)
  avx512_1
  x86_64 (supported, searched)
holger at ionos15-amd64:~ $ 

holger at ionos15-amd64:~ $ cat /proc/cpuinfo |head -28
processor	: 0
vendor_id	: GenuineIntel
cpu family	: 6
model		: 60
model name	: Intel Core Processor (Haswell)
stepping	: 1
microcode	: 0x1
cpu MHz		: 2394.454
cache size	: 4096 KB
physical id	: 0
siblings	: 2
core id		: 0
cpu cores	: 1
apicid		: 0
initial apicid	: 0
fpu		: yes
fpu_exception	: yes
cpuid level	: 13
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx pdpe1gb rdtscp lm constant_tsc rep_good nopl xtopology cpuid tsc_known_freq pni pclmulqdq vmx ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm cpuid_fault pti ssbd ibrs ibpb stibp tpr_shadow flexpriority ept vpid ept_ad fsgsbase bmi1 hle avx2 smep bmi2 erms invpcid rtm xsaveopt arat vnmi md_clear
vmx flags	: vnmi preemption_timer posted_intr invvpid ept_x_only ept_ad ept_1gb flexpriority apicv tsc_offset vtpr mtf vapic ept vpid unrestricted_guest vapic_reg vid shadow_vmcs
bugs		: cpu_meltdown spectre_v1 spectre_v2 spec_store_bypass l1tf mds swapgs taa itlb_multihit srbds mmio_unknown bhi
bogomips	: 4788.90
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management:

I don't have access to ionos1 running that CPU anymore, as IONOS
asked me to migrate machines away from precicely that CPU type,
so here is the same command on ionos11:


holger at ionos11-amd64:~ $ /lib/x86_64-linux-gnu/ld-linux-x86-64.so.2 --help
Usage: /lib/x86_64-linux-gnu/ld-linux-x86-64.so.2 [OPTION]... EXECUTABLE-FILE [ARGS-FOR-PROGRAM...]
[...]
This program interpreter self-identifies as: /lib64/ld-linux-x86-64.so.2

Shared library search path:
  (libraries located via /etc/ld.so.cache)
  /lib/x86_64-linux-gnu (system search path)
  /usr/lib/x86_64-linux-gnu (system search path)
  /lib (system search path)
  /usr/lib (system search path)

Subdirectories of glibc-hwcaps directories, in priority order:
  x86-64-v4
  x86-64-v3
  x86-64-v2 (supported, searched)

Legacy HWCAP subdirectories under library search path directories:
  x86_64 (AT_PLATFORM; supported, searched)
  tls (supported, searched)
  avx512_1
  x86_64 (supported, searched)
holger at ionos11-amd64:~ $ 

holger at ionos11-amd64:~ $ cat /proc/cpuinfo |head -28
processor	: 0
vendor_id	: AuthenticAMD
cpu family	: 21
model		: 1
model name	: AMD Opteron 62xx class CPU
stepping	: 2
microcode	: 0x1000065
cpu MHz		: 2600.000
cache size	: 512 KB
physical id	: 0
siblings	: 1
core id		: 0
cpu cores	: 1
apicid		: 0
initial apicid	: 0
fpu		: yes
fpu_exception	: yes
cpuid level	: 13
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall nx mmxext pdpe1gb rdtscp lm rep_good nopl cpuid extd_apicid tsc_known_freq pni pclmulqdq ssse3 cx16 sse4_1 sse4_2 x2apic popcnt aes xsave avx hypervisor lahf_lm cmp_legacy svm abm sse4a misalignsse 3dnowprefetch osvw ssbd ibpb vmmcall virt_ssbd arat npt nrip_save
bugs		: fxsave_leak sysret_ss_attrs null_seg spectre_v1 spectre_v2 spec_store_bypass retbleed ibpb_no_ret
bogomips	: 5200.00
TLB size	: 1024 4K pages
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management:


Please note that both CPUs are vitualised (running on that actual CPU hardware).


-- 
cheers,
	Holger

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