[Bug target/98667] gcc generates endbr32 invalid opcode on -march=i486

[tedheadster at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98667

--- Comment #4 from Matthew Whitehead <tedheadster at gmail dot com> ---
It looks like /usr/bin/gdb 10.1 also has this opcode in it:

objdump -D /usr/bin/gdb | grep -B6 -A6 endbr32 

  60d7b5:       3f                      aas    
  60d7b6:       1a 3b                   sbb    (%ebx),%bh
  60d7b8:       2a 32                   sub    (%edx),%dh
  60d7ba:       24 22                   and    $0x22,%al
  60d7bc:       00 00                   add    %al,(%eax)
  60d7be:       00 00                   add    %al,(%eax)
  60d7c0:       f3 0f 1e fb             endbr32 
  60d7c4:       ff a3 00 00 00 00       jmp    *0x0(%ebx)
  60d7ca:       66 0f 1f 44 00 00       nopw   0x0(%eax,%eax,1)
  60d7d0:       f3 0f 1e fb             endbr32 
  60d7d4:       ff 25 00 00 00 00       jmp    *0x0
  60d7da:       66 0f 1f 44 00 00       nopw   0x0(%eax,%eax,1)
  60d7e0:       ff b3 04 00 00 00       pushl  0x4(%ebx)
  60d7e6:       ff a3 08 00 00 00       jmp    *0x8(%ebx)
  60d7ec:       0f 1f 40 00             nopl   0x0(%eax)
  60d7f0:       f3 0f 1e fb             endbr32 
  60d7f4:       68 00 00 00 00          push   $0x0
  60d7f9:       e9 00 00 00 00          jmp    60d7fe
<_IO_stdin_used@@Base+0xd77fa>
  60d7fe:       66 90                   xchg   %ax,%ax
  60d800:       ff 35 00 00 00 00       pushl  0x0
  60d806:       ff 25 00 00 00 00       jmp    *0x0
  60d80c:       0f 1f 40 00             nopl   0x0(%eax)

i686-pentium4-mpentium4-lenovo /usr/lib/debug/usr/bin # /usr/bin/gdb --version 
GNU gdb (Gentoo 10.1 vanilla) 10.1
Copyright (C) 2020 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

I will provide the gcc compile switches if asked, but it is long: 2156 items.