[Bug c++/105293] g++-8/i586: internal compiler error trying to compile with g++ (evtl. related to qt5/moc bug)

["estellnb at elstel dot org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105293

--- Comment #5 from Elmar Stellnberger <estellnb at elstel dot org> ---
Created attachment 52827
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52827&action=edit
2nd version of patch that should be useable under gcc-8-8.3.0/debian/patches/

  Last time I reported that I could not test the patch posted here because the
result of package creation with dpkg-buildpackage had vanished. Luckily I found
gcc/xg++ and gcc/xgcc which were the required executables that could be
installed into /bin/ and tested whether they compiled the new Firefox.

  g++ with the last patch did not do this. Consequently I have checked out
10.2.2, newer than the last known working good one (10.1.1) from Debian 11 and
analysed all changes along the backtrace again. What I found is condensed in
the patch above:

discover_nonconstant_array_refs ();   -  was moved up in addition to the other
change tested already before

  If the error is evoked by what is called along the backtrace this needs to
resolve it. (I assume now that the Qt5/moc bug is independent and do not use it
as reference for the gcc version to compare against any more). Otherwise, the
error may stem from something done in a previous pass:

during RTL pass: expand

  Unfortunately this time I was not even able to compile gcc/xg++. Makefiles
were garbled, xgcc did not produce a.out (test in Makefile), texinfo files were
invalid and I had to copy them from a fresh root and ultimately xg++ stayed the
same after all. I had rescued the original g++ as /bin/g++ and that one turned
into a link (I know it was a regular file before) although all debian/rules
Makefiles only ship into debian/tmp/usr/... and not /.
  Absolutely no chance to test this second patch! Perhaps someone else can do.