[SOLVED] Illegal instruction при явном указании архитектуры haswell

Имеется машинка с процом:

cpu family      : 6
model           : 60
model name      : Intel(R) Pentium(R) CPU G3240 @ 3.10GHz
stepping        : 3
microcode       : 0x28

Решил ускорить пересборку пакетов. Подключил/настроил distcc, прописал флаги CFLAGS в явном виде вместо -march=native:

-march=haswell -mmmx -msse -msse2 -msse3 -mssse3 -mcx16 -msahf -mmovbe -mpclmul -mpopcnt -mabm -msse4.2 -msse4.1 -mlzcnt -mrdrnd -mfsgsbase -mfxsr --param l1-cache-size=32 --param l1-cache-line-size=64 --param l2-cache-size=3072 -mtune=haswell

В первом десятке пакетов был bash. После него словил Illegal instruction. Откатил python-exec и bash, чтобы оживить систему. Начал разбираться. Причина оказалась вовсе не в distcc, а в локальном gcc. Достаточно прописать CFLAGS="-O2 -pipe -march=haswell", чтобы после компиляции получать неисполняемые бинарники.

Что-то на своем опыте таких фокусов не встречал, Гугл тоже не помог. Прошу помощи. HELP!

Дополнительно:

# eselect profile show
Current /etc/make.profile symlink:
  default/linux/amd64/17.0

# gcc --version
gcc (Gentoo 9.3.0-r1 p3) 9.3.0

# uname -a
Linux *** 5.4.48-gentoo-x86_64 #1 SMP Sun Jul 26 23:26:23 MSK 2020 x86_64 Intel(R) Pentium(R) CPU G3240 @ 3.10GHz GenuineIntel GNU/Linux

# emerge --info
Portage 3.0.4 (python 3.7.8-final-0, default/linux/amd64/17.0, gcc-9.3.0, glibc-2.31-r6, 5.4.48-gentoo-x86_64 x86_64)
=================================================================
System uname: 
KiB Mem:     8027128 total,    516156 free
KiB Swap:    3904508 total,   3903732 free
Timestamp of repository gentoo: Fri, 25 Sep 2020 01:00:01 +0000
Head commit of repository gentoo: 79f78dd6c987b2f6df22617ce0a6a38c2ef979a4
sh bash 5.0_p18
ld GNU ld (Gentoo 2.33.1 p2) 2.33.1
distcc 3.3.3 x86_64-pc-linux-gnu [disabled]
ccache version 3.7.10 [disabled]
app-shells/bash:          5.0_p18::gentoo
dev-java/java-config:     2.3.1::gentoo
dev-lang/perl:            5.30.3::gentoo
dev-lang/python:          2.7.18-r1::gentoo, 3.6.11-r2::gentoo, 3.7.8-r2::gentoo, 3.8.5::gentoo
dev-util/ccache:          3.7.10::gentoo
dev-util/cmake:           3.16.5::gentoo
dev-util/pkgconfig:       0.29.2::gentoo
sys-apps/baselayout:      2.7::gentoo
sys-apps/openrc:          0.42.1::gentoo
sys-apps/sandbox:         2.18::gentoo
sys-devel/autoconf:       2.13-r1::gentoo, 2.69-r4::gentoo
sys-devel/automake:       1.16.1-r1::gentoo
sys-devel/binutils:       2.33.1-r1::gentoo
sys-devel/gcc:            9.3.0-r1::gentoo
sys-devel/gcc-config:     2.3.1::gentoo
sys-devel/libtool:        2.4.6-r6::gentoo
sys-devel/make:           4.2.1-r4::gentoo
sys-kernel/linux-headers: 5.4-r1::gentoo (virtual/os-headers)
sys-libs/glibc:           2.31-r6::gentoo
Repositories:

gentoo
    location: /usr/portage
    sync-type: rsync
    sync-uri: rsync://rsync.gentoo.org/gentoo-portage
    priority: -1000
    sync-rsync-extra-opts:
    sync-rsync-verify-max-age: 24
    sync-rsync-verify-jobs: 1
    sync-rsync-verify-metamanifest: yes

borodux-dyndns-org
    location: /usr/local/portage/overlay
    masters: gentoo
    priority: 0

ACCEPT_KEYWORDS="amd64"
ACCEPT_LICENSE="@FREE"
CBUILD="x86_64-pc-linux-gnu"
CFLAGS="-O2 -pipe -march=native"
CHOST="x86_64-pc-linux-gnu"
CONFIG_PROTECT="/etc /usr/share/easy-rsa /usr/share/gnupg/qualified.txt /usr/share/maven-bin-3.6/conf"
CONFIG_PROTECT_MASK="/etc/ca-certificates.conf /etc/dconf /etc/env.d /etc/fonts/fonts.conf /etc/gconf /etc/gentoo-release /etc/php/apache2-php7.2/ext-active/ /etc/php/apache2-php7.3/ext-active/ /etc/php/apache2-php7.4/ext-active/ /etc/php/cgi-php7.2/ext-active/ /etc/php/cgi-php7.3/ext-active/ /etc/php/cgi-php7.4/ext-active/ /etc/php/cli-php7.2/ext-active/ /etc/php/cli-php7.3/ext-active/ /etc/php/cli-php7.4/ext-active/ /etc/revdep-rebuild /etc/sandbox.d /etc/terminfo"
CXXFLAGS="-O2 -pipe -march=native"
DISTDIR="/var/portage/distfiles"
EMERGE_DEFAULT_OPTS="--with-bdeps=y --keep-going"
ENV_UNSET="CARGO_HOME DBUS_SESSION_BUS_ADDRESS DISPLAY GOBIN GOPATH PERL5LIB PERL5OPT PERLPREFIX PERL_CORE PERL_MB_OPT PERL_MM_OPT XAUTHORITY XDG_CACHE_HOME XDG_CONFIG_HOME XDG_DATA_HOME XDG_RUNTIME_DIR"
FCFLAGS="-O2 -pipe"
FEATURES="assume-digests binpkg-docompress binpkg-dostrip binpkg-logs config-protect-if-modified distlocks ebuild-locks fixlafiles ipc-sandbox merge-sync multilib-strict network-sandbox news parallel-fetch pid-sandbox preserve-libs protect-owned qa-unresolved-soname-deps sandbox sfperms strict unknown-features-warn unmerge-logs unmerge-orphans userfetch userpriv usersandbox usersync"
FFLAGS="-O2 -pipe"
GENTOO_MIRRORS="http://distfiles.gentoo.org"
LANG="en_US.UTF-8"
LDFLAGS="-Wl,-O1 -Wl,--as-needed"
LINGUAS="en ru"
MAKEOPTS="-j10 -l3"
PKGDIR="/var/cache/binpkgs"
PORTAGE_CONFIGROOT="/"
PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --omit-dir-times --compress --force --whole-file --delete --stats --human-rea
dable --timeout=180 --exclude=/distfiles --exclude=/local --exclude=/packages --exclude=/.git"
PORTAGE_TMPDIR="/var/tmp"
USE="X acl alsa amd64 bash-completion berkdb bzip2 cli crypt curl dbus dri elogind ffmpeg flac fortran gdbm gif iconv idn ipv6 jpeg libglvnd libtirpc lzma matroska multilib ncurses nls nptl opengl openmp pam pcre png readline seccomp split-usr ssl tcpd threads tiff unicode vaapi x264 xattr zlib" ABI_X86="64" ADA_TARGET="gnat_2018" ALSA_CARDS="ali5451 als4000 atiixp atiixp-modem bt87x ca0106 cmipci emu10k1x ens1370 ens1371 es1938 es1968 fm801 hda-intel intel8x0 intel8x0m maestro3 trident usb-audio via82xx via82xx-modem ymfpci" APACHE2_MODULES="authn_core authz_core socache_shmcb unixd actions alias auth_basic authn_alias authn_anon authn_dbm authn_default authn_file authz_dbm authz_default authz_groupfile authz_host authz_owner authz_user autoindex cache cgi cgid dav dav_fs dav_lock deflate dir disk_cache env expires ext_filter file_cache filter headers include info log_config logio mem_cache mime mime_magic negotiation rewrite setenvif speling status unique_id userdir usertrack vhost_alias proxy proxy_scgi" CALLIGRA_FEATURES="karbon sheets words" COLLECTD_PLUGINS="df interface irq load memory rrdtool swap syslog" CPU_FLAGS_X86="mmx mmxext popcnt sse sse2 sse3 sse4_1 sse4_2 ssse3" ELIBC="glibc" GPSD_PROTOCOLS="ashtech aivdm earthmate evermore fv18 garmin garmintxt gpsclock greis isync itrax mtk3301 nmea ntrip navcom oceanserver oldstyle oncore rtcm104v2 rtcm104v3 sirf skytraq superstar2 timing tsip tripmate tnt ublox ubx" GRUB_PLATFORMS="efi-32 efi-64 pc multiboot" INPUT_DEVICES="libinput" KERNEL="linux" L10N="en ru" LCD_DEVICES="bayrad cfontz cfontz633 glk hd44780 lb216 lcdm001 mtxorb ncurses text" LIBREOFFICE_EXTENSIONS="presenter-console presenter-minimizer" OFFICE_IMPLEMENTATION="libreoffice" PHP_TARGETS="php7-2 php7-3 php7-4" POSTGRES_TARGETS="postgres10 postgres11" PYTHON_SINGLE_TARGET="python3_7" PYTHON_TARGETS="python2_7 python3_7" RUBY_TARGETS="ruby25 ruby26" USERLAND="GNU" VIDEO_CARDS="intel i965" XTABLES_ADDONS="quota2 psd pknock lscan length2 ipv4options ipset ipp2p iface geoip fuzzy condition tee tarpit sysrq steal rawnat logmark ipmark dhcpmac delude chaos account"
Unset:  CC, CPPFLAGS, CTARGET, CXX, INSTALL_MASK, LC_ALL, PORTAGE_BINHOST, PORTAGE_BUNZIP2_COMMAND, PORTAGE_COMPRESS, PORTAGE_COMPRESS_FLAGS, PORTAGE_RSYNC_EXTRA_OPTS