[Bug bootstrap/42628] New: [4.4 regression] ICE during bootstrap when compiling dyncast.cc: original tree changed by fold

["matt at use dot net" <gcc-bugzilla at gcc dot gnu dot org>]

X-Bugzilla-Reason: CC

doing a profiledbootstrap with trunk revision 155656, I ran into this crash:
/home/matt/src/gcc-obj/./gcc/xgcc -shared-libgcc -B/home/matt/src/gcc-obj/./gcc
-nostdinc++ -L/home/matt/src/gcc-obj/x86_64-unknown-linux-gnu/libstdc++-v3/src
-L/home/matt/src/gcc-obj/x86_64-unknown-linux-gnu/libstdc++-v3/src/.libs
-B/usr/local/x86_64-unknown-linux-gnu/bin/
-B/usr/local/x86_64-unknown-linux-gnu/lib/ -isystem
/usr/local/x86_64-unknown-linux-gnu/include -isystem
/usr/local/x86_64-unknown-linux-gnu/sys-include
-I/home/matt/src/gcc-trunk/libstdc++-v3/../gcc
-I/home/matt/src/gcc-obj/x86_64-unknown-linux-gnu/libstdc++-v3/include/x86_64-unknown-linux-gnu
-I/home/matt/src/gcc-obj/x86_64-unknown-linux-gnu/libstdc++-v3/include
-I/home/matt/src/gcc-trunk/libstdc++-v3/libsupc++ -fno-implicit-templates -Wall
-Wextra -Wwrite-strings -Wcast-qual -fdiagnostics-show-location=once
-ffunction-sections -fdata-sections -g -O0 -Wuninitialized -Warray-bounds
-D_GNU_SOURCE -c ../gcc-trunk/libstdc++-v3/libsupc++/dyncast.cc  -fPIC -DPIC -o
~/crashmatt@hargett-755:~/src/gcc-obj$ /home/matt/src/gcc-obj/./gcc/xgcc
-shared-libgcc -B/home/matt/src/gcc-obj/./gcc -nostdinc++
-L/home/matt/src/gcc-obj/x86_64-unknown-linux-gnu/libstdc++-v3/src
-L/home/matt/src/gcc-obj/x86_64-unknown-linux-gnu/libstdc++-v3/src/.libs
-B/usr/local/x86_64-unknown-linux-gnu/bin/
-B/usr/local/x86_64-unknown-linux-gnu/lib/ -isystem
/usr/local/x86_64-unknown-linux-gnu/include -isystem
/usr/local/x86_64-unknown-linux-gnu/sys-include
-I/home/matt/src/gcc-trunk/libstdc++-v3/../gcc
-I/home/matt/src/gcc-obj/x86_64-unknown-linux-gnu/libstdc++-v3/include/x86_64-unknown-linux-gnu
-I/home/matt/src/gcc-obj/x86_64-unknown-linux-gnu/libstdc++-v3/include
-I/home/matt/src/gcc-trunk/libstdc++-v3/libsupc++ -fno-implicit-templates -Wall
-Wextra -Wwrite-strings -Wcast-qual -fdiagnostics-show-location=once
-ffunction-sections -fdata-sections -g -O1 -Wuninitialized -Warray-bounds
-D_GNU_SOURCE -c ../gcc-trunk/libstdc++-v3/libsupc++/dyncast.cc  -fPIC -DPIC -o
~/crash      
../gcc-trunk/libstdc++-v3/libsupc++/dyncast.cc: In function ‘void*
__cxxabiv1::__dynamic_cast(const void*, const __cxxabiv1::__class_type_info*,
const __cxxabiv1::__class_type_info*, ptrdiff_t)’:                        
../gcc-trunk/libstdc++-v3/libsupc++/dyncast.cc:86:1: internal compiler error:
fold check: original tree changed by fold

valgrind 3.5.0 doesn't find anything worth reporting.

Note that I used BOOT_CFLAGS and CFLAGS of -O3 -g, but in the commandline above
I reduced it to -O1 as that still evoked the crash. -O0 works fine. Curiously,
I couldn't reproduce when I manually added all the individual options listed
for -O1 in the 4.5 man page. (Maybe the man page is missing one of the
options?)

I didn't see this issue when I did a profiledbootstrap about 4 weeks ago.
Compiling the same file and same options with GCC 4.4 and 4.3 doesn't crash,
and neither provides any notable valgrind output.


-- 
           Summary: [4.4 regression] ICE during bootstrap when compiling
                    dyncast.cc: original tree changed by fold
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: bootstrap
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: matt at use dot net
 GCC build triplet: x86_64-unknown-linux-gnu
  GCC host triplet: x86_64-unknown-linux-gnu
GCC target triplet: x86_64-unknown-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42628