https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87099
Bug ID: 87099
Summary: internal compiler error: segmentation fault
Product: gcc
Version: 8.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: rtl-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: moron at waifu dot club
Target Milestone: ---
Created attachment 44593
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=44593&action=edit
the preprocessed file from -save-temps
Code to reproduce:
#include <stdio.h>
#include <string.h>
int main(int argc, char const *argv[]){
char myArray[argc];
int a = strncmp(&(myArray[1]),"aaaa",3);
return 0;
}
Compiler command to reproduce:
gcc test.c
Note:
This does not happen if the size of myArray is just a constant number. If the
strlen of the second argument to strncmp is less than the third argument, the
bug does not happen. If you remove the "int a = " part and just do nothing with
the return value of strncmp then the bug does not happen. I was able to compile
this code last month, probably using GCC 8.1.
Output with verbose:
gcc -save-temps --verbose test4.c
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-pc-linux-gnu/8.2.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /build/gcc/src/gcc/configure --prefix=/usr --libdir=/usr/lib
--libexecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info
--with-bugurl=https://bugs.archlinux.org/
--enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++ --enable-shared
--enable-threads=posix --enable-libmpx --with-system-zlib --with-isl
--enable-__cxa_atexit --disable-libunwind-exceptions --enable-clocale=gnu
--disable-libstdcxx-pch --disable-libssp --enable-gnu-unique-object
--enable-linker-build-id --enable-lto --enable-plugin
--enable-install-libiberty --with-linker-hash-style=gnu
--enable-gnu-indirect-function --enable-multilib --disable-werror
--enable-checking=release --enable-default-pie --enable-default-ssp
--enable-cet=auto
Thread model: posix
gcc version 8.2.0 (GCC)
COLLECT_GCC_OPTIONS='-save-temps' '-v' '-mtune=generic' '-march=x86-64'
/usr/lib/gcc/x86_64-pc-linux-gnu/8.2.0/cc1 -E -quiet -v test4.c -mtune=generic
-march=x86-64 -fpch-preprocess -o test4.i
ignoring nonexistent directory
"/usr/lib/gcc/x86_64-pc-linux-gnu/8.2.0/../../../../x86_64-pc-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/lib/gcc/x86_64-pc-linux-gnu/8.2.0/include
/usr/local/include
/usr/lib/gcc/x86_64-pc-linux-gnu/8.2.0/include-fixed
/usr/include
End of search list.
COLLECT_GCC_OPTIONS='-save-temps' '-v' '-mtune=generic' '-march=x86-64'
/usr/lib/gcc/x86_64-pc-linux-gnu/8.2.0/cc1 -fpreprocessed test4.i -quiet
-dumpbase test4.c -mtune=generic -march=x86-64 -auxbase test4 -version -o
test4.s
GNU C17 (GCC) version 8.2.0 (x86_64-pc-linux-gnu)
compiled by GNU C version 8.2.0, GMP version 6.1.2, MPFR version 4.0.1,
MPC version 1.1.0, isl version isl-0.19-GMP
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
GNU C17 (GCC) version 8.2.0 (x86_64-pc-linux-gnu)
compiled by GNU C version 8.2.0, GMP version 6.1.2, MPFR version 4.0.1,
MPC version 1.1.0, isl version isl-0.19-GMP
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 374c644ab4db4fa02e30fa5669d43e86
during RTL pass: expand
test4.c: In function ‘main’:
test4.c:6:10: internal compiler error: Segmentation fault
int a = strncmp(&(myArray[1]),"aaaa",3);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Please submit a full bug report,
with preprocessed source if appropriate.
See <https://bugs.archlinux.org/> for instructions.
