[Bug rtl-optimization/115785] ICE when building embree-4.3.1 on amd64 with -flate-combine-instructions

[rsandifo at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115785

--- Comment #2 from Richard Sandiford <rsandifo at gcc dot gnu.org> ---
The patch in #c1 is just part 1.  Part 2 will fix the bug.