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

[estellnb at elstel dot org]

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

            Bug ID: 105293
           Summary: g++-8/i586: internal compiler error trying to compile
                    with g++ (evtl. related to qt5/moc bug)
           Product: gcc
           Version: 8.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: estellnb at elstel dot org
  Target Milestone: ---

Created attachment 52821
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52821&action=edit
command line to evoke the error

If I try to compile firefox-esr-91.8.0esr I get the following error in (command
line in evoke-compilererr):

In file included from src/gl.cc:2643:
src/rasterize.h: In function ‘void draw_quad_spans(int, Point2D*, uint32_t,
glsl::Interpolants*, Texture&, Texture&, const ClipRect&) [with P = unsigned
char]’:
src/rasterize.h:782:20: internal compiler error: in convert_move, at expr.c:218
 static inline void draw_quad_spans(int nump, Point2D p[4], uint32_t z,
                    ^~~~~~~~~~~~~~~
0xf78b7b40 __libc_start_main
        ../csu/libc-start.c:308
Please submit a full bug report,

  If I run /bin/g++ (g++ 4:8.3.0-1 i386 Debian10/Buster) in gdb:
(gdb) l
1       ../sysdeps/unix/sysv/linux/i386/init-first.c: file not found
(gdb) bt
No stack.

  The error is known and does not appear in the same version of amd64 Debian.
It does not appear with newer versions like Debian11/Bullseye/g++ 4:10.2.1-1

  I get another type of error with Qt5/moc (meta object compiler for generating
signal handler procedure signatures):
usr/include/c++/8/bits/stl_relops.:67: Parse error at "std"

  /usr/include/c++/8/bits/stl_relops.h start like any .h in bits/ and should be
correct. Like the internal compiler error from above this one appears only in
i586, but with a wide variety of distributions:
i586 Debian10 gcc 8.3.0-1: bad  (likewise bad Ubuntu19.04)
i586 Ubuntu19.10 gcc 9.2.1: good

  I will appreciate any hint to what the bug could have been related to. I
would like to develop a patch to fix things for Debian10/i386 but do not really
know on where to start looking for. I could neither find init-first.c nor
libc-start.c looking for such files in the source directory gcc-8-8.3.0.