[Bug target/81763] Issues with 32bit x86 apps on GCC 7.1+

[mike at fireburn dot co.uk]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81763

--- Comment #3 from Mike Lothian  ---
So dropping the -march=native allows everything to work again no matter which
version of GCC

Just using -mbmi breaks things and using -march=native -mno-bmi allows it all
to work

This is on a Skylake processor with the following in /proc/cpuinfo

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 cpuid aperfmperf tsc_known_freq pni pclmulqdq dtes64 monitor ds_cpl
vmx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe
popcnt aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault epb
intel_pt tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 hle
avx2 smep bmi2 erms invpcid rtm mpx rdseed adx smap clflushopt xsaveopt xsavec
xgetbv1 xsaves dtherm ida arat pln pts hwp hwp_notify hwp_act_window hwp_epp

[Bug target/81763] Issues with 32bit x86 apps on GCC 7.1+

[mike at fireburn dot co.uk]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81763

--- Comment #2 from Mike Lothian  ---
Sorry I should have been more clear, this is LLVM trunk

I'm using these flags: 

CFLAGS="-O2 -march=native -pipe"
CXXFLAGS="-O2 -march=native -pipe"
LDFLAGS="-Wl,-O1 -Wl,--hash-style=gnu -Wl,--as-needed"

gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-pc-linux-gnu/7.1.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with:
/var/tmp/portage/sys-devel/gcc-7.1.0-r1/work/gcc-7.1.0/configure
--host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu --prefix=/usr
--bindir=/usr/x86_64-pc-linux-gnu/gcc-bin/7.1.0
--includedir=/usr/lib/gcc/x86_64-pc-linux-gnu/7.1.0/include
--datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/7.1.0
--mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/7.1.0/man
--infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/7.1.0/info
--with-gxx-include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/7.1.0/include/g++-v7
--with-python-dir=/share/gcc-data/x86_64-pc-linux-gnu/7.1.0/python
--enable-languages=c,c++,fortran --enable-obsolete --enable-secureplt
--disable-werror --with-system-zlib --enable-nls --without-included-gettext
--enable-checking=release --with-bugurl=https://bugs.gentoo.org/
--with-pkgversion='Gentoo 7.1.0-r1 p1.1' --disable-esp --enable-libstdcxx-time
--enable-shared --enable-threads=posix --enable-__cxa_atexit
--enable-clocale=gnu --enable-multilib --with-multilib-list=m32,m64
--disable-altivec --disable-fixed-point --enable-targets=all --disable-libgcj
--enable-libgomp --disable-libmudflap --disable-libssp --disable-libcilkrts
--enable-libmpx --enable-vtable-verify --enable-libvtv --enable-lto --with-isl
--disable-isl-version-check --enable-libsanitizer --disable-default-pie
--disable-default-ssp
Thread model: posix
gcc version 7.1.0 (Gentoo 7.1.0-r1 p1.1)

[Bug target/81763] Issues with 32bit x86 apps on GCC 7.1+

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81763

--- Comment #1 from Andrew Pinski  ---
There are some known issues with older versions of LLVM, maybe you are using
too older version of LLVM.  That is some versions of LLVM have undefined C++
code in them.  GCC 7.1 is more aggressive of optimizing things.