invalid CPU instruction in chromium built with LLVM 6.0

[Mikhail Novosyolov]

Chromium crashed randomly:
$ dmesg
[ 7383.735592] traps: chromium-browse[15302] trap invalid opcode ip:55da81b19cc5 sp:7fff229f1c88 error:0 in chromium-browser[55da7f11b000+838f000]

It has happened only once so far and I can't reproduce the crash.
Maybe it is somehow connected with clang bugs which lead to chromium being unable to start on i586 due to invalid CPU instructions (opcodes):
https://bugzilla.altlinux.org/show_bug.cgi?id=34742
https://bugzilla.altlinux.org/show_bug.cgi?id=34722

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: chromium-browser 65.0.3325.181-0ubuntu1
Uname: Linux 4.16.6-041606-generic x86_64
ApportVersion: 2.20.9-0ubuntu7
Architecture: amd64
CurrentDesktop: XFCE
DRM.card0-DVI-D-1:
 enabled: enabled
 dpms: On
 status: connected
 edid-base64: AP///////wBBDAHBomUAAC4aAQOAMx14KtkFpVdRnicPUFS9SwDRwJUAlQ+zAIHAgYCBQAEBAjqAGHE4LUBYLEUA/R4RAAAeAAAA/wBVSEIxNjQ2MDI2MDE4AAAA/ABQSEwgMjM3RTcKICAgAAAA/QA4TB5TEQAKICAgICAgANk=
 modes: 1920x1080 1680x1050 1280x1024 1280x1024 1440x900 1440x900 1280x960 1280x720 1024x768 1024x768 800x600 800x600 640x480 640x480 640x480 640x480 720x400
DRM.card0-HDMI-A-1:
 enabled: disabled
 dpms: On
 status: disconnected
 edid-base64:
 modes:
DRM.card0-VGA-1:
 enabled: disabled
 dpms: On
 status: disconnected
 edid-base64:
 modes:
Date: Wed May 2 19:30:26 2018
Desktop-Session:
 'xubuntu'
 '/etc/xdg/xdg-xubuntu:/etc/xdg:/usr/share/kubuntu-default-settings/kf5-settings:/etc/xdg'
 '/usr/share/xfce4:/usr/share/xubuntu:/usr/local/share:/usr/share:/var/lib/snapd/desktop:/var/lib/snapd/desktop:/usr/share'
DetectedPlugins:

Env:
 'None'
 'None'
InstallationDate: Installed on 2017-08-28 (247 days ago)
InstallationMedia: Xubuntu 17.04 "Zesty Zapus" - Release amd64 (20170412)
Load-Avg-1min: 1.87
Load-Processes-Running-Percent: 0.2%
MachineType: ASUS All Series
ProcKernelCmdLine: BOOT_IMAGE=/@/boot/vmlinuz-4.16.6-041606-generic root=UUID=355fccdc-c430-43b5-929b-f38e35136c1c ro rootflags=subvol=@
SourcePackage: chromium-browser
UpgradeStatus: Upgraded to bionic on 2018-02-08 (83 days ago)
dmi.bios.date: 03/10/2016
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 0801
dmi.board.asset.tag: To be filled by O.E.M.
dmi.board.name: AM1I-A
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: Rev X.0x
dmi.chassis.asset.tag: Asset-1234567890
dmi.chassis.type: 3
dmi.chassis.vendor: Chassis Manufacture
dmi.chassis.version: Chassis Version
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr0801:bd03/10/2016:svnASUS:pnAllSeries:pvrSystemVersion:rvnASUSTeKCOMPUTERINC.:rnAM1I-A:rvrRevX.0x:cvnChassisManufacture:ct3:cvrChassisVersion:
dmi.product.family: ASUS MB
dmi.product.name: All Series
dmi.product.version: System Version
dmi.sys.vendor: ASUS
modified.conffile..etc.default.chromium-browser: [deleted]