@Victor:
Thanks - same preprocessor diagnostics and lrint() inlining as my Core2 64-bit OS X build, so you're probably right re. the strange behavior of the Mingw64-based scalar-code compilation. As long as the SIMD builds work, a low-priority issue, to be sure.

Hello! Tried compile mlucas on Intel(R) Xeon(R) Gold 5120 CPU @ 2.20GHz with AVX512 but without success. For now i haven't access to this system however i would like to post my experience:
[CODE]processor : 55
vendor_id : GenuineIntel
cpu family : 6
model : 85
model name : Intel(R) Xeon(R) Gold 5120 CPU @ 2.20GHz
stepping : 4
microcode : 0x200003a
cpu MHz : 2200.000
cache size : 19712 KB
physical id : 1
siblings : 28
core id : 11
cpu cores : 14
apicid : 55
initial apicid : 55
fpu : yes
fpu_exception : yes
cpuid level : 22
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf eagerfpu pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 fma cx16 xtpr pdcm pcid dca sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch epb cat_l3 cdp_l3 invpcid_single intel_pt spec_ctrl ibpb_support tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm cqm mpx rdt_a avx512f avx512dq rdseed adx smap clflushopt clwb avx512cd avx512bw avx512vl xsaveopt xsavec xgetbv1 cqm_llc cqm_occup_llc cqm_mbm_total cqm_mbm_local dtherm ida arat pln pts
bogomips : 4404.53
clflush size : 64
cache_alignment : 64
address sizes : 46 bits physical, 48 bits virtual
power management:


[root@lorenzo3 src]# gcc --version
gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-16)
Copyright (C) 2015 Free Software Foundation, Inc.
Это свободно распространяемое программное обеспечение. Условия копирования
приведены в исходных текстах. Без гарантии каких-либо качеств, включая
коммерческую ценность и применимость для каких-либо целей.

[root@lorenzo3 src]# gcc -c -O3 [B]-DUSE_AVX512 -march=skylake-avx512[/B] -DUSE_THREADS ../src/*.c >& build.log

[root@lorenzo3 src]# cat build.log
../src/br.c:1:0: ошибка: [B]bad value (skylake-avx512) for -march= switch[/B]
/*******************************************************************************
^
../src/dft_macro.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/factor.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/fermat_mod_square.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/fgt_m61.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/gcd_lehmer.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/get_cpuid.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/get_fft_radices.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/get_fp_rnd_const.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/get_preferred_fft_radix.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/getRealTime.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
// EWM: June 2014 - Code from http://nadeausoftware.com/articles/2012/04/c_c_tip_how_measure_elapsed_real_time_benchmarking
^
../src/imul_macro.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/mers_mod_square.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/mi64.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/Mlucas.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/pairFFT_mul.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/qfloat.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix1008_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix1024_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix104_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix10_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix112_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix11_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix120_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix128_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix12_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix13_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix144_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix14_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix15_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix160_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix16_dif_dit_pass.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix16_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix16_dyadic_square.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix16_pairFFT_mul.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix16_wrapper_ini.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix16_wrapper_square.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix176_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix18_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix192_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix208_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix20_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix224_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix22_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix240_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix24_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix256_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix26_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix288_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix28_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix30_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix31_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix32_dif_dit_pass.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix32_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix32_dyadic_square.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix32_wrapper_ini.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix32_wrapper_square.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix36_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix4032_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix40_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix44_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix48_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix512_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix52_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix56_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix5_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix60_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix63_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix64_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix6_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix72_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix768_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix7_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix80_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix88_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix8_dif_dit_pass.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix8_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix960_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix96_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix992_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/radix9_ditN_cy_dif1.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/rng_isaac.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*
^
../src/test_fft_radix.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/threadpool.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
// EWM: This threadpool file has "more history" than the other Mlucas sources,
^
../src/twopmodq100.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/twopmodq128_96.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/twopmodq128.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/twopmodq160.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/twopmodq192.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/twopmodq256.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/twopmodq64_test.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/twopmodq80.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/twopmodq96.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/twopmodq.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/types.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
../src/util.c:1:0: ошибка: bad value (skylake-avx512) for -march= switch
/*******************************************************************************
^
[/CODE]

Is that version of GCC too old to support avx512 on skylake xeons?

I'm pretty sure your gcc doesn't support -march=skylake-avx512 as I get a similar output with -march=randomjunk
You probably need to update to the latest gcc, I don't know if they backport tuning for new architectures.

Skylake AVX512 support was introduced in GCC 6 according to the release note:
[url]https://gcc.gnu.org/gcc-6/changes.html[/url]

It may not help with pre-v5 gcc, but might be worth trying -march=knl instead ... the code performance is dominated by my custom asm macros which are all restricted to the avx512 Foundation Instructions subset supported by the KNL, so whether the compiler thinks it's compiling for skylake-avx512 or KNL shouldn't matter, as long as the arch flag enables avx512 instruction generation in the back end.

FYI, the version of gcc on the KNL I used for avx-512 code development is 5.4, i.e. pre-v6.

It's no longer the newest version. Please change thread title.

[QUOTE=kriesel;528037]It's no longer the newest version. Please change thread title.[/QUOTE]

Alas, I don't have thread-edit permissions, not even in this particular subforum. I've e-mailed Mike to ask if that is intended.

[QUOTE=ewmayer;528102]Alas, I don't have thread-edit permissions, not even in this particular subforum. I've e-mailed Mike to ask if that is intended.[/QUOTE]It now appears the V17.1 thread title and V18 sticky have been handled. (Now if Mike would just authorize 30-hour-day lengths, V19 could soon be ready, and repeat.)