[Bug tree-optimization/105650] [13 Regression] Possibly wrong code on fontforge -fvect-cost-model=unlimited

[slyfox at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105650

--- Comment #3 from Sergei Trofimovich <slyfox at gcc dot gnu.org> ---
(In reply to Hongtao.liu from comment #1)
> What's the platform are you running on, does it with SSE2?
> GCC default arch is SSE2, and I didn't see any suspicious obove-sse2
> instruction.

It's a znver3 CPU:

$ LANG=C lscpu
Architecture:            x86_64
  CPU op-mode(s):        32-bit, 64-bit
  Address sizes:         48 bits physical, 48 bits virtual
  Byte Order:            Little Endian
CPU(s):                  32
  On-line CPU(s) list:   0-15
  Off-line CPU(s) list:  16-31
Vendor ID:               AuthenticAMD
  Model name:            AMD Ryzen 9 5950X 16-Core Processor
    CPU family:          25
    Model:               33
    Thread(s) per core:  1
    Core(s) per socket:  16
    Socket(s):           1
    Stepping:            0
    Frequency boost:     enabled
    CPU max MHz:         5083.3979
    CPU min MHz:         0.0000
    BogoMIPS:            6787.31
    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 mmxext fxsr_opt
pdpe1gb rdtscp lm constant_tsc rep_good nopl nonstop_tsc cpu
                         id extd_apicid aperfmperf rapl pni pclmulqdq monitor
ssse3 fma cx16 sse4_1 sse4_2 movbe popcnt aes xsave avx f16c rdrand lahf_lm
cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dn
                         owprefetch osvw ibs skinit wdt tce topoext
perfctr_core perfctr_nb bpext perfctr_llc mwaitx cpb cat_l3 cdp_l3 hw_pstate
ssbd mba ibrs ibpb stibp vmmcall fsgsbase bmi1 avx2 smep bmi2 erms i
                         nvpcid cqm rdt_a rdseed adx smap clflushopt clwb
sha_ni xsaveopt xsavec xgetbv1 xsaves cqm_llc cqm_occup_llc cqm_mbm_total
cqm_mbm_local clzero irperf xsaveerptr rdpru wbnoinvd arat npt lb
                         rv svm_lock nrip_save tsc_scale vmcb_clean flushbyasid
decodeassists pausefilter pfthreshold avic v_vmsave_vmload vgif v_spec_ctrl
umip pku ospke vaes vpclmulqdq rdpid overflow_recov succo
                         r smca fsrm
Virtualization features:
  Virtualization:        AMD-V
Caches (sum of all):
  L1d:                   512 KiB (16 instances)
  L1i:                   512 KiB (16 instances)
  L2:                    8 MiB (16 instances)
  L3:                    64 MiB (2 instances)
NUMA:
  NUMA node(s):          1
  NUMA node0 CPU(s):     0-15
Vulnerabilities:
  Itlb multihit:         Not affected
  L1tf:                  Not affected
  Mds:                   Not affected
  Meltdown:              Not affected
  Spec store bypass:     Vulnerable
  Spectre v1:            Vulnerable: __user pointer sanitization and usercopy
barriers only; no swapgs barriers
  Spectre v2:            Vulnerable, IBPB: disabled, STIBP: disabled
  Srbds:                 Not affected
  Tsx async abort:       Not affected


I think the problem for me is value mismatch in compare of `if (v != cnt)
__builtin_trap();`. Invalid instruction is generated by `__builtin_trap()`.