https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70145
Bug ID: 70145
Summary: g++-5 and g++-6: invalid code generated for
-fno-elide-constructors and constexpr array
Product: gcc
Version: 5.3.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: robert-gcc at debian dot org
Target Milestone: ---
Created attachment 37900
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=37900&action=edit
Simplified test case
The attached simplified code gives different results when compiled with
-fno-elide-constructors with g++-6:
The expected behaviour:
/tmp/tst> g++-6 -Wall -Wextra --std=c++1y ./test.cpp -o test
/tmp/tst> ./test; echo $?
1
The incorrect output with -fno-elide-constructors:
/tmp/tst> g++-6 -Wall -Wextra --std=c++1y -fno-elide-constructors ./test.cpp
-o test
/tmp/tst> ./test; echo $?
0
The same issue exists in g++-5. The issue is not reproducible in g++-4.9.
Versions:
* g++-6:
Using built-in specs.
COLLECT_GCC=g++-6
COLLECT_LTO_WRAPPER=/usr/lib/gcc/i586-linux-gnu/6/lto-wrapper
Target: i586-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Debian 6-20160228-1'
--with-bugurl=file:///usr/share/doc/gcc-6/README.Bugs
--enable-languages=c,ada,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-6 --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes
--with-default-libstdcxx-abi=new --enable-gnu-unique-object
--disable-vtable-verify --enable-libmpx --enable-plugin --with-system-zlib
--disable-browser-plugin --enable-java-awt=gtk --enable-gtk-cairo
--with-java-home=/usr/lib/jvm/java-1.5.0-gcj-6-i386/jre --enable-java-home
--with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-6-i386
--with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-6-i386
--with-arch-directory=i386 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar
--enable-objc-gc --enable-targets=all --enable-multiarch --with-arch-32=i586
--with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic
--enable-checking=release --build=i586-linux-gnu --host=i586-linux-gnu
--target=i586-linux-gnu
Thread model: posix
gcc version 6.0.0 20160228 (experimental) [trunk revision 233789] (Debian
6-20160228-1)
COLLECT_GCC_OPTIONS='-v' '-std=c++11' '-shared-libgcc' '-mtune=generic'
'-march=i586'
/usr/lib/gcc/i586-linux-gnu/6/cc1plus -quiet -v -imultiarch i386-linux-gnu
-D_GNU_SOURCE ./test.cpp -quiet -dumpbase test.cpp -mtune=generic -march=i586
-auxbase test -std=c++11 -version -o /tmp/user/1000/ccOuyw8T.s
GNU C++11 (Debian 6-20160228-1) version 6.0.0 20160228 (experimental) [trunk
revision 233789] (i586-linux-gnu)
compiled by GNU C version 6.0.0 20160228 (experimental) [trunk revision
233789], GMP version 6.1.0, MPFR version 3.1.4-rc1, MPC version 1.0.3, isl
version 0.15
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
ignoring duplicate directory "/usr/include/i386-linux-gnu/c++/6"
ignoring nonexistent directory "/usr/local/include/i386-linux-gnu"
ignoring nonexistent directory
"/usr/lib/gcc/i586-linux-gnu/6/../../../../i586-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/include/c++/6
/usr/include/i386-linux-gnu/c++/6
/usr/include/c++/6/backward
/usr/lib/gcc/i586-linux-gnu/6/include
/usr/local/include
/usr/lib/gcc/i586-linux-gnu/6/include-fixed
/usr/include/i386-linux-gnu
/usr/include
End of search list.
GNU C++11 (Debian 6-20160228-1) version 6.0.0 20160228 (experimental) [trunk
revision 233789] (i586-linux-gnu)
compiled by GNU C version 6.0.0 20160228 (experimental) [trunk revision
233789], GMP version 6.1.0, MPFR version 3.1.4-rc1, MPC version 1.0.3, isl
version 0.15
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 36ae62cc8c2555d6cda1e59f88303dae
COLLECT_GCC_OPTIONS='-v' '-std=c++11' '-shared-libgcc' '-mtune=generic'
'-march=i586'
as -v --32 -o /tmp/user/1000/ccJITulw.o /tmp/user/1000/ccOuyw8T.s
GNU assembler version 2.26 (i686-linux-gnu) using BFD version (GNU Binutils for
Debian) 2.26
COMPILER_PATH=/usr/lib/gcc/i586-linux-gnu/6/:/usr/lib/gcc/i586-linux-gnu/6/:/usr/lib/gcc/i586-linux-gnu/:/usr/lib/gcc/i586-linux-gnu/6/:/usr/lib/gcc/i586-linux-gnu/
LIBRARY_PATH=/usr/lib/gcc/i586-linux-gnu/6/:/usr/lib/gcc/i586-linux-gnu/6/../../../i386-linux-gnu/:/usr/lib/gcc/i586-linux-gnu/6/../../../../lib/:/lib/i386-linux-gnu/:/lib/../lib/:/usr/lib/i386-linux-gnu/:/usr/lib/../lib/:/usr/lib/gcc/i586-linux-gnu/6/../../../:/lib/:/usr/lib/
COLLECT_GCC_OPTIONS='-v' '-std=c++11' '-shared-libgcc' '-mtune=generic'
'-march=i586'
/usr/lib/gcc/i586-linux-gnu/6/collect2 -plugin
/usr/lib/gcc/i586-linux-gnu/6/liblto_plugin.so
-plugin-opt=/usr/lib/gcc/i586-linux-gnu/6/lto-wrapper
-plugin-opt=-fresolution=/tmp/user/1000/ccd7jTD8.res
-plugin-opt=-pass-through=-lgcc_s -plugin-opt=-pass-through=-lgcc
-plugin-opt=-pass-through=-lc -plugin-opt=-pass-through=-lgcc_s
-plugin-opt=-pass-through=-lgcc --sysroot=/ --build-id --eh-frame-hdr -m
elf_i386 --hash-style=gnu -dynamic-linker /lib/ld-linux.so.2
/usr/lib/gcc/i586-linux-gnu/6/../../../i386-linux-gnu/crt1.o
/usr/lib/gcc/i586-linux-gnu/6/../../../i386-linux-gnu/crti.o
/usr/lib/gcc/i586-linux-gnu/6/crtbegin.o -L/usr/lib/gcc/i586-linux-gnu/6
-L/usr/lib/gcc/i586-linux-gnu/6/../../../i386-linux-gnu
-L/usr/lib/gcc/i586-linux-gnu/6/../../../../lib -L/lib/i386-linux-gnu
-L/lib/../lib -L/usr/lib/i386-linux-gnu -L/usr/lib/../lib
-L/usr/lib/gcc/i586-linux-gnu/6/../../.. /tmp/user/1000/ccJITulw.o -lstdc++ -lm
-lgcc_s -lgcc -lc -lgcc_s -lgcc /usr/lib/gcc/i586-linux-gnu/6/crtend.o
/usr/lib/gcc/i586-linux-gnu/6/../../../i386-linux-gnu/crtn.o
COLLECT_GCC_OPTIONS='-v' '-std=c++11' '-shared-libgcc' '-mtune=generic'
'-march=i586'
* g++-5:
Using built-in specs.
COLLECT_GCC=g++-5
COLLECT_LTO_WRAPPER=/usr/lib/gcc/i586-linux-gnu/5/lto-wrapper
Target: i586-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Debian 5.3.1-10'
--with-bugurl=file:///usr/share/doc/gcc-5/README.Bugs
--enable-languages=c,ada,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-5 --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes
--with-default-libstdcxx-abi=new --enable-gnu-unique-object
--disable-vtable-verify --enable-libmpx --enable-plugin --with-system-zlib
--disable-browser-plugin --enable-java-awt=gtk --enable-gtk-cairo
--with-java-home=/usr/lib/jvm/java-1.5.0-gcj-5-i386/jre --enable-java-home
--with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-5-i386
--with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-5-i386
--with-arch-directory=i386 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar
--enable-objc-gc --enable-targets=all --enable-multiarch --with-arch-32=i586
--with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic
--enable-checking=release --build=i586-linux-gnu --host=i586-linux-gnu
--target=i586-linux-gnu
Thread model: posix
gcc version 5.3.1 20160224 (Debian 5.3.1-10)
COLLECT_GCC_OPTIONS='-v' '-std=c++11' '-shared-libgcc' '-mtune=generic'
'-march=i586'
/usr/lib/gcc/i586-linux-gnu/5/cc1plus -quiet -v -imultiarch i386-linux-gnu
-D_GNU_SOURCE ./test.cpp -quiet -dumpbase test.cpp -mtune=generic -march=i586
-auxbase test -std=c++11 -version -o /tmp/user/1000/cc6KLQj2.s
GNU C++11 (Debian 5.3.1-10) version 5.3.1 20160224 (i586-linux-gnu)
compiled by GNU C version 5.3.1 20160224, GMP version 6.1.0, MPFR
version 3.1.4-rc1, MPC version 1.0.3
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
ignoring duplicate directory "/usr/include/i386-linux-gnu/c++/5"
ignoring nonexistent directory "/usr/local/include/i386-linux-gnu"
ignoring nonexistent directory
"/usr/lib/gcc/i586-linux-gnu/5/../../../../i586-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/include/c++/5
/usr/include/i386-linux-gnu/c++/5
/usr/include/c++/5/backward
/usr/lib/gcc/i586-linux-gnu/5/include
/usr/local/include
/usr/lib/gcc/i586-linux-gnu/5/include-fixed
/usr/include/i386-linux-gnu
/usr/include
End of search list.
GNU C++11 (Debian 5.3.1-10) version 5.3.1 20160224 (i586-linux-gnu)
compiled by GNU C version 5.3.1 20160224, GMP version 6.1.0, MPFR
version 3.1.4-rc1, MPC version 1.0.3
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: de01ec571655bf8f7044198a3eee7769
COLLECT_GCC_OPTIONS='-v' '-std=c++11' '-shared-libgcc' '-mtune=generic'
'-march=i586'
as -v --32 -o /tmp/user/1000/ccXsoKTP.o /tmp/user/1000/cc6KLQj2.s
GNU assembler version 2.26 (i686-linux-gnu) using BFD version (GNU Binutils for
Debian) 2.26
COMPILER_PATH=/usr/lib/gcc/i586-linux-gnu/5/:/usr/lib/gcc/i586-linux-gnu/5/:/usr/lib/gcc/i586-linux-gnu/:/usr/lib/gcc/i586-linux-gnu/5/:/usr/lib/gcc/i586-linux-gnu/
LIBRARY_PATH=/usr/lib/gcc/i586-linux-gnu/5/:/usr/lib/gcc/i586-linux-gnu/5/../../../i386-linux-gnu/:/usr/lib/gcc/i586-linux-gnu/5/../../../../lib/:/lib/i386-linux-gnu/:/lib/../lib/:/usr/lib/i386-linux-gnu/:/usr/lib/../lib/:/usr/lib/gcc/i586-linux-gnu/5/../../../:/lib/:/usr/lib/
COLLECT_GCC_OPTIONS='-v' '-std=c++11' '-shared-libgcc' '-mtune=generic'
'-march=i586'
/usr/lib/gcc/i586-linux-gnu/5/collect2 -plugin
/usr/lib/gcc/i586-linux-gnu/5/liblto_plugin.so
-plugin-opt=/usr/lib/gcc/i586-linux-gnu/5/lto-wrapper
-plugin-opt=-fresolution=/tmp/user/1000/ccPU3JyD.res
-plugin-opt=-pass-through=-lgcc_s -plugin-opt=-pass-through=-lgcc
-plugin-opt=-pass-through=-lc -plugin-opt=-pass-through=-lgcc_s
-plugin-opt=-pass-through=-lgcc --sysroot=/ --build-id --eh-frame-hdr -m
elf_i386 --hash-style=gnu -dynamic-linker /lib/ld-linux.so.2
/usr/lib/gcc/i586-linux-gnu/5/../../../i386-linux-gnu/crt1.o
/usr/lib/gcc/i586-linux-gnu/5/../../../i386-linux-gnu/crti.o
/usr/lib/gcc/i586-linux-gnu/5/crtbegin.o -L/usr/lib/gcc/i586-linux-gnu/5
-L/usr/lib/gcc/i586-linux-gnu/5/../../../i386-linux-gnu
-L/usr/lib/gcc/i586-linux-gnu/5/../../../../lib -L/lib/i386-linux-gnu
-L/lib/../lib -L/usr/lib/i386-linux-gnu -L/usr/lib/../lib
-L/usr/lib/gcc/i586-linux-gnu/5/../../.. /tmp/user/1000/ccXsoKTP.o -lstdc++ -lm
-lgcc_s -lgcc -lc -lgcc_s -lgcc /usr/lib/gcc/i586-linux-gnu/5/crtend.o
/usr/lib/gcc/i586-linux-gnu/5/../../../i386-linux-gnu/crtn.o
