https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123655
Bug ID: 123655
Summary: [16 regression] glibc test stdlib/tst-makecontext
FAILs for x32 with -O3 -march=znver2
Product: gcc
Version: 16.0
Status: UNCONFIRMED
Keywords: wrong-code
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: sjames at gcc dot gnu.org
CC: hjl.tools at gmail dot com
Target Milestone: ---
```
$ ./testrun.sh stdlib/tst-makecontext --verbose --direct
Segmentation fault (core dumped) ./testrun.sh stdlib/tst-makecontext
--verbose --direct
```
```
$ ./debugglibc.sh stdlib/tst-makecontext
[...]
Program received signal SIGSEGV, Segmentation fault.
Downloading 39.94 K source file
/usr/src/debug/sys-devel/gcc-16.0.9999/gcc-16.0.9999/libgcc/unwind-dw2.c
_Unwind_GetPtr (context=0xf7fb4e00, index=16) at
/usr/src/debug/sys-devel/gcc-16.0.9999/gcc-16.0.9999/libgcc/unwind-dw2.c:260
260 return (void *)(_Unwind_Ptr) _Unwind_GetGR (context, index);
(gdb) bt
#0 _Unwind_GetPtr (context=0xf7fb4e00, index=16) at
/usr/src/debug/sys-devel/gcc-16.0.9999/gcc-16.0.9999/libgcc/unwind-dw2.c:260
#1 uw_update_context (context=0xf7fb4e00, fs=0xf7fb4ee0) at
/usr/src/debug/sys-devel/gcc-16.0.9999/gcc-16.0.9999/libgcc/unwind-dw2.c:1296
#2 _Unwind_Backtrace (trace=0xf7fac760, trace_argument=0xf7fb5010) at
/usr/src/debug/sys-devel/gcc-16.0.9999/gcc-16.0.9999/libgcc/unwind.inc:326
#3 0xf7fac7e6 in ?? ()
#4 0x00000001 in ?? ()
#5 0x00000000 in ?? ()
```
```
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-pc-linux-gnu/16/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-pc-linux-gnu
Configured with:
/var/tmp/portage.notmp/portage/sys-devel/gcc-16.0.9999/work/gcc-16.0.9999/configure
--host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu --prefix=/usr
--bindir=/usr/x86_64-pc-linux-gnu/gcc-bin/16
--includedir=/usr/lib/gcc/x86_64-pc-linux-gnu/16/include
--datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/16
--mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/16/man
--infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/16/info
--with-gxx-include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/16/include/g++-v16
--disable-silent-rules --disable-dependency-tracking
--with-python-dir=/share/gcc-data/x86_64-pc-linux-gnu/16/python
--enable-libphobos --enable-objc-gc
--enable-languages=c,c++,d,go,objc,obj-c++,fortran,ada,cobol,algol68,m2,rust,jit
--enable-obsolete --enable-secureplt --disable-werror --with-system-zlib
--enable-nls --without-included-gettext --disable-libunwind-exceptions
--enable-checking=yes,extra,rtl --with-bugurl=https://bugs.gentoo.org/
--with-pkgversion='Gentoo Hardened 16.0.9999 p, commit
7c21ad7fdb7c7bf93e1a17a60756da03a21b16e7' --with-gcc-major-version-only
--enable-libstdcxx-time --enable-lto --disable-libstdcxx-pch --enable-shared
--enable-threads=posix --enable-__cxa_atexit --enable-clocale=gnu
--with-tls=gnu2 --enable-multilib --with-multilib-list=m32,mx32,m64
--disable-fixed-point --with-abi=m64 --enable-targets=all
--enable-offload-defaulted --enable-offload-targets=nvptx-none --enable-libgomp
--disable-libssp --enable-libada --disable-cet --enable-systemtap
--enable-valgrind-annotations --enable-valgrind-interop --disable-vtable-verify
--disable-libvtv --with-zstd --with-isl --disable-isl-version-check
--enable-default-pie --enable-host-pie --enable-host-bind-now
--enable-default-ssp --disable-fixincludes
--with-gxx-libcxx-include-dir=/usr/include/c++/v1 --enable-host-shared
--enable-libgdiagnostics --enable-linker-build-id --enable-linker-build-id
--enable-linker-build-id --enable-linker-build-id
--with-build-config='bootstrap-O3 bootstrap-lto'
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 16.0.1 20260117 (experimental)
8ec17a01f1fc76a53f0f2a7e0cff0c460aac4635 (Gentoo Hardened 16.0.9999 p, commit
7c21ad7fdb7c7bf93e1a17a60756da03a21b16e7)
```
