[Bug lto/88147] [9 Regression] ICE in linemap_line_start, at libcpp/line-map.c:781 starting from r265875

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88147

--- Comment #11 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
Created attachment 45610
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=45610&action=edit
Partially reduced testcase

This is 975366 bytes (decompressed) and takes 0.3-0.4 seconds to crash
r265875's lto1, as compared to the ~15MB and 2.5 minutes it took for the
original attachment.