[Bug c++/80451] New: return implicit type conversion to std::optional does not compile
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80451 Bug ID: 80451 Summary: return implicit type conversion to std::optional does not compile Product: gcc Version: 6.3.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: krisk0.2017.02.27 at protonmail dot com Target Milestone: --- Host: x86_64-pc-linux-gnu Target: x86_64-pc-linux-gnu Build: x86_64-pc-linux-gnu Created attachment 41213 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41213&action=edit preprocessed source * Short story: under certain conditions, `return v;` statement does not compile. * the exact version of GCC; gcc-6.3.0 (Gentoo 6.3.0 p1.0) 6.3.0 * the system type; Gentoo on x86_64 * the options given when GCC was configured/built; COLLECT_GCC=gcc-6.3.0 COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-pc-linux-gnu/6.3.0/lto-wrapper Target: x86_64-pc-linux-gnu Configured with: /tmp/portage/sys-devel/gcc-6.3.0/work/gcc-6.3.0/configure --host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu --prefix=/usr --bindir=/usr/x86_64-pc-linux-gnu/gcc-bin/6.3.0 --includedir=/usr/lib/gcc/x86_64-pc-linux-gnu/6.3.0/include --datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/6.3.0 --mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/6.3.0/man --infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/6.3.0/info --with-gxx-include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/6.3.0/include/g++-v6 --with-python-dir=/share/gcc-data/x86_64-pc-linux-gnu/6.3.0/python --enable-languages=c,c++ --enable-obsolete --enable-secureplt --disable-werror --with-system-zlib --disable-nls --enable-checking=release --with-bugurl=https://bugs.gentoo.org/ --with-pkgversion='Gentoo 6.3.0 p1.0' --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 --disable-libmpx --enable-vtable-verify --enable-libvtv --disable-libquadmath --enable-lto --without-isl --enable-libsanitizer --disable-default-pie --disable-default-ssp Thread model: posix gcc version 6.3.0 (Gentoo 6.3.0 p1.0) * the complete command line that triggers the bug; gcc-6.3.0 -xc++ -O2 -std=gnu++14 return-bug.c * the compiler output (error messages, warnings, etc.); return-bug.cc: In function 'std::experimental::fundamentals_v1::optional meal(std::__cxx11::string)': return-bug.cc:39:12: error: could not convert 'b' from 'Bread_and_butter' to 'std::experimental::fundamentals_v1::optional' return b; ^ * the preprocessed file (*.i*) that triggers the bug see attachment * Why the code should compile 1. According to C++ standard §6.6.3 `The value of the expression is implicitly converted to the return type of the function in which it appears.` 2. According to http://en.cppreference.com/w/cpp/experimental/optional/optional, non-explicit constructor from T& to std::experimental::optional should exist. 3. The code compiles under gcc 5.4
[Bug libstdc++/80451] return implicit type conversion to std::experimental::optional does not compile
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80451 --- Comment #2 from Денис Крыськов --- None of official documents I read says that optional invokes copy-constructor of T. Jonathan, did you describe a change in specification, or a temporary walkaround?
[Bug libstdc++/80451] [6/7 Regression] return implicit type conversion to std::experimental::optional does not compile
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80451 --- Comment #6 from Денис Крыськов --- Seems like a serious bug in compiler. Jonathan, thanks for quick investigation.
[Bug libstdc++/80451] [6/7 Regression] return implicit type conversion to std::experimental::optional does not compile
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80451 --- Comment #8 from Денис Крыськов --- If I understand correctly, http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#1579 is not implemented in gcc 5.4 and 6.3. Which means some code runs slower than is should. To be sure that a fast constructor is called, I need to delete slow constructor. Which results in bloated code (each and every class should contain delete statement). If that's not serious, that's unpleasant.
[Bug libstdc++/79743] New: std::experimental::optional constructor broken in gcc 6.2
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79743 Bug ID: 79743 Summary: std::experimental::optional constructor broken in gcc 6.2 Product: gcc Version: lto Status: UNCONFIRMED Severity: normal Priority: P3 Component: libstdc++ Assignee: unassigned at gcc dot gnu.org Reporter: krisk0.2017.02.27 at protonmail dot com Target Milestone: --- Created attachment 40841 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40841&action=edit all files mentioned in bug-report Short story: std::experimental::optional copy-constructor is broken under GCC 6.2. 47-line .cpp proves it. Long story as required by https://gcc.gnu.org/bugs/: * the exact version of GCC sys-devel/gcc-5.3.0 --- works fine sys-devel/gcc-6.2.0 --- buggy * the system type Gentoo on amd64 (Intel Core i5) * the options given when GCC was configured/built See files 5.3.configure and 6.2.configure * the complete command line that triggers the bug Install Google test --- package dev-cpp/gtest; g++ -std=c++14 -O2 -lgtest test.cpp && ./a.out Test passes under gcc 5.3 and fails under 6.2. std::experimental::optional constructor sets butter to false though it should be undefined. * the compiler output (error messages, warnings) None * the preprocessed file (*.i*) test.5.3.ii --- works fine, test passes test.6.2.ii --- test fails ``` test.cpp:40: Failure Value of: !s1.butter Actual: false Expected: true test.cpp:40: Failure Value of: Nothing Actual: 1-byte object <00> Expected: s1.butter Which is: 2-byte object <00-01> ```
[Bug libstdc++/79743] std::experimental::optional constructor broken in gcc 6.2
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79743 --- Comment #2 from Денис Крыськов --- ok, will provided standalone .cpp next time. Jonathan, thank you.
[Bug c/80345] New: ICE in rewrite_use_nonlinear_expr with -O2
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80345 Bug ID: 80345 Summary: ICE in rewrite_use_nonlinear_expr with -O2 Product: gcc Version: 6.3.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c Assignee: unassigned at gcc dot gnu.org Reporter: krisk0.2017.02.27 at protonmail dot com Target Milestone: --- The bug looks like #68021. But #68021 has been fixed Feb 2016 and gcc-6.3 is dated Dec 2016, so this bug is NOT a duplicate. * the exact version of GCC gcc version 6.3.0 (Gentoo 6.3.0 p1.0) 4.9.3 5.3 5.4 affected, too. clang 3.7.1 compiles fine. * the system type Gentoo Linux on amd64 * the options given when GCC was configured/built; COLLECT_GCC=/usr/x86_64-pc-linux-gnu/gcc-bin/6.3.0/gcc COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-pc-linux-gnu/6.3.0/lto-wrapper Target: x86_64-pc-linux-gnu Configured with: /tmp/portage/sys-devel/gcc-6.3.0/work/gcc-6.3.0/configure --host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu --prefix=/usr --bindir=/usr/x86_64-pc-linux-gnu/gcc-bin/6.3.0 --includedir=/usr/lib/gcc/x86_64-pc-linux-gnu/6.3.0/include --datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/6.3.0 --mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/6.3.0/man --infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/6.3.0/info --with-gxx-include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/6.3.0/include/g++-v6 --with-python-dir=/share/gcc-data/x86_64-pc-linux-gnu/6.3.0/python --enable-languages=c,c++ --enable-obsolete --enable-secureplt --disable-werror --with-system-zlib --disable-nls --enable-checking=release --with-bugurl=https://bugs.gentoo.org/ --with-pkgversion='Gentoo 6.3.0 p1.0' --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 --disable-libmpx --enable-vtable-verify --enable-libvtv --disable-libquadmath --enable-lto --without-isl --enable-libsanitizer --disable-default-pie --disable-default-ssp Thread model: posix gcc version 6.3.0 (Gentoo 6.3.0 p1.0) * the complete command line that triggers the bug; x86_64-pc-linux-gnu-gcc -O2 -pipe -march=native -fPIC -I/usr/lib64/python2.7/site-packages/sage/ext -I/usr/lib64/python2.7/site-packages -I/usr/lib64/python2.7/site-packages/cysignals -I/usr/include/python2.7 -c flint.c -o /tmp/portage/dev-python/python-sage-flint-20150625-r0/work/razin-20150625-r0/flint.binding-python2_7/temp.linux-x86_64-2.7/flint.o * the compiler output (error messages, warnings, etc.); and the preprocessed file (*.i*) that triggers the bug In file included from flint.c:483:0: C/fmpz_mat/det_suspected_zero.c: In function 'det_divisor_count_y': C/fmpz_mat/det_suspected_zero.c:180:33: warning: initialization from incompatible pointer type [-Wincompatible-pointer-types] const mp_limb_t** const m_row=m->rows; ^ In file included from flint.c:489:0: C/fmpz_mat/Hadamard_Cramer.c: In function 'hadamard_2arg': C/fmpz_mat/Hadamard_Cramer.c:127:27: warning: initialization from incompatible pointer type [-Wincompatible-pointer-types] const fmpz** const rows=m->rows; ^ In file included from flint.c:492:0: C/nmod_mat/det_mod_pk.c: In function 'nmod_mat_det_dim4': C/nmod_mat/det_mod_pk.c:122:32: warning: initialization from incompatible pointer type [-Wincompatible-pointer-types] const mp_limb_t** const rows=M->rows; ^ C/nmod_mat/det_mod_pk.c: In function 'nmod_mat_det_dim4_SE': C/nmod_mat/det_mod_pk.c:142:32: warning: initialization from incompatible pointer type [-Wincompatible-pointer-types] const mp_limb_t** const rows=M->rows; ^ C/nmod_mat/det_mod_pk.c: In function 'nmod_mat_det_dim3': C/nmod_mat/det_mod_pk.c:168:32: warning: initialization from incompatible pointer type [-Wincompatible-pointer-types] const mp_limb_t** const rows=A->rows; ^ In file included from flint.c:496:0: C/nmod_mat/transpose_square_tgt_virgin.c: In function 'nmod_mat_transpose_square_tgt_virgin': C/nmod_mat/transpose_square_tgt_virgin.c:11:36: warning: initialization from incompatible pointer type [-Wincompatible-pointer-types] const mp_limb_t** const sou_rows=sou->rows; ^ In file included from flint.c:491:0: C/tmod_mat/invert_square.c: In function 'tmod_mat_invert_transpose': C/tmod_mat/invert_square.c:226:1: internal compiler error: in rewrite_use_nonlinear_expr, at tree-ssa-loop-ivopts.c:6448 tmod_mat_invert_transpose(tmod_mat_t R, const tmod_mat_t S) ^ Please submit a full bug report, with preprocessed source if appropriate. Se
[Bug tree-optimization/80345] ICE in rewrite_use_nonlinear_expr with -O2
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80345 --- Comment #2 from Денис Крыськов --- Created attachment 41148 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41148&action=edit the preprocessed file Ah, sorry, I attached uncompressed file, which was rejected due to big size.
[Bug tree-optimization/80345] [5 Regression] ICE in rewrite_use_nonlinear_expr with -O2
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80345 --- Comment #7 from Денис Крыськов --- Created attachment 41149 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41149&action=edit gcc5.4 -v stderr/stdout
[Bug tree-optimization/80345] [5 Regression] ICE in rewrite_use_nonlinear_expr with -O2
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80345 --- Comment #8 from Денис Крыськов --- (In reply to Markus Trippelsdorf from comment #4) > 6.3 branch works fine. > Only 5.4.1 is affected. So it looks like a missing backport. Microarch is Haswell. I failed to reproduce ICE with gcc 6.3. If this is due to my mistake, I am sorry. I attached gcc 5.4 stderr/stdout.
