https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82878
Bug ID: 82878
Summary: ICE in assign_temp, at function.c:968 when using
optimization
Product: gcc
Version: 7.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: ksundenkamsc12 at gmail dot com
Target Milestone: ---
This bug is possibly related to Bug 79989 and/or Bug 82148, but presents itself
in a slightly different manner than in either of those examples.
The short version:
The following command, given the preprocessed source file provided, produces an
ICE:
```
$ g++ --verbose -c fd_array.ii -O
Using built-in specs.
COLLECT_GCC=g++
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 --disable-multilib --disable-werror
--enable-checking=release --enable-default-pie --enable-default-ssp
Thread model: posix
gcc version 7.2.0 (GCC)
COLLECT_GCC_OPTIONS='-v' '-c' '-O' '-shared-libgcc' '-mtune=generic'
'-march=x86-64'
/usr/lib/gcc/x86_64-pc-linux-gnu/7.2.0/cc1plus -fpreprocessed fd_array.ii
-quiet -dumpbase fd_array.ii -mtune=generic -march=x86-64 -auxbase fd_array -O
-version -o /tmp/ccOdsz5s.s
GNU C++14 (GCC) version 7.2.0 (x86_64-pc-linux-gnu)
compiled by GNU C version 7.2.0, GMP version 6.1.2, MPFR version
3.1.5-p2, MPC version 1.0.3, isl version isl-0.18-GMP
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
GNU C++14 (GCC) version 7.2.0 (x86_64-pc-linux-gnu)
compiled by GNU C version 7.2.0, GMP version 6.1.2, MPFR version
3.1.5-p2, MPC version 1.0.3, isl version isl-0.18-GMP
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 5931a2fe3d5a5365a85e56248f3f55d7
sim/fd_array.cc: In member function ‘void FDArray::restoreFileOffsets()’:
sim/fd_array.cc:143:5: internal compiler error: in assign_temp, at
function.c:968
};
^
Please submit a full bug report,
with preprocessed source if appropriate.
See <https://bugs.archlinux.org/> for instructions.
```
Note, this report is from GCC 7.2.0 running on Arch Linux, but I also observed
the same error message using GCC 7.2.1 running on OpenSUSE Tumbleweed.
Additional information:
This code does compile with no optimization flag or with '-O0', but any other
'-O' flag triggers this bug (including '-Ofast' and '-Og').
I was unable to trigger the bug purely by adding optimization flags, even when
specifying all flags listed under -O1 at:
https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html:
$ g++ -c fd_array.ii -fauto-inc-dec -fbranch-count-reg
-fcombine-stack-adjustments -fcompare-elim -fcprop-registers -fdce -fdefer-pop
-fdelayed-branch -fdse -fforward-propagate -fguess-branch-probability
-fif-conversion2 -fif-conversion -finline-functions-called-once
-fipa-pure-const -fipa-profile -fipa-reference -fmerge-constants
-fmove-loop-invariants -freorder-blocks -fshrink-wrap -fshrink-wrap-separate
-fsplit-wide-types -fssa-backprop -fssa-phiopt -ftree-bit-ccp -ftree-ccp
-ftree-ch -ftree-coalesce-vars -ftree-copy-prop -ftree-dce
-ftree-dominator-opts -ftree-dse -ftree-forwprop -ftree-fre -ftree-phiprop
-ftree-sink -ftree-slsr -ftree-sra -ftree-pta -ftree-ter -funit-at-a-time
-fomit-frame-pointer
This produces one warning on my machine due to the -fdelayed-branch flag which
is unsupported by the target machine.
In point of fact, I specified all flags from -O1, -O2, and -O3, and had no
error.
I was able to trigger the ICE using the flags from Bug 79989 ('$ g++ -c
fd_array.ii -mmpx -fcheck-pointer-bounds '), but this produced additional
output and is not listed as flags which are provided by the '-O' flag (namely,
this treated the function as a static member function rather than simply a
"member function"):
sim/fd_array.cc: In static member function ‘static void
FDArray::restoreFileOffsets()::<lambda(std::shared_ptr<FileFDEntry>)>::_FUN.chkp(std::shared_ptr<FileFDEntry>,
\xe2\x80\x98pointer_bounds_typ\xe2\x80\x99 not supported by dump_type#<type
error>, void, ...)’:
sim/fd_array.cc:143:5: internal compiler error: in assign_temp, at
function.c:968
};
^
The original code compiles with g++-6 (though the g++-7 preprocessed file
provided here does not complete compilation with g++-6)
The source file is from the gem5 cpu simulator, BSD 3-clause licensed
