https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117243
Bug ID: 117243
Summary: program crash under -O3 optimization or higher
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: bouncy12578 at gmail dot com
Target Milestone: ---
$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc-14
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-linux-gnu/14/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none:amdgcn-amdhsa
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu
14-20240412-0ubuntu1' --with-bugurl=file:///usr/share/doc/gcc-14/README.Bugs
--enable-languages=c,ada,c++,go,d,fortran,objc,obj-c++,m2,rust --prefix=/usr
--with-gcc-major-version-only --program-suffix=-14
--program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id
--libexecdir=/usr/libexec --without-included-gettext --enable-threads=posix
--libdir=/usr/lib --enable-nls --enable-clocale=gnu --enable-libstdcxx-debug
--enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new
--enable-libstdcxx-backtrace --enable-gnu-unique-object --disable-vtable-verify
--enable-plugin --enable-default-pie --with-system-zlib
--enable-libphobos-checking=release --with-target-system-zlib=auto
--enable-objc-gc=auto --enable-multiarch --disable-werror --enable-cet
--with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32
--enable-multilib --with-tune=generic
--enable-offload-targets=nvptx-none=/build/gcc-14-OQFzmN/gcc-14-14-20240412/debian/tmp-nvptx/usr,amdgcn-amdhsa=/build/gcc-14-OQFzmN/gcc-14-14-20240412/debian/tmp-gcn/usr
--enable-offload-defaulted --without-cuda-driver
--enable-checking=yes,extra,rtl --build=x86_64-linux-gnu
--host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 14.0.1 20240412 (experimental) [master r14-9935-g67e1433a94f]
(Ubuntu 14-20240412-0ubuntu1)
$ cat a.c
void foo(int a, int b) {
int i, j;
j:
for (b=0; b<2; b++)
{
int c[1][1];
int i, j;
for (i = 0; i < 1; i++)
for (j = 0; j < 1; j++)
c[i][j] = 1;
if (b)
goto j;
}
}
int main() {
foo(1, 2);
}
$ gcc a.c -O3 && ./a.out
Segmentation fault (core dumped)
$ gcc a.c && ./a.out
(infinite loop, the program won't stop)
This bug can be reproduced on gcc 14 and trunk.
Any further modification would eliminate bug.
The program is a designed inifinite loop. It would crash under -O3(or higher)
optimization. -O0, -O1, -O2 won't cause segmentation fault.
Interestingly, if param b in func foo is unsigned, the bug can be reproduced on
gcc 13(12 or lower cannot reproduce it)
