[Bug tree-optimization/77498] [7 regression] Performance drop after r239414 on spec2000/172mgrid

[thopre01 at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77498

--- Comment #9 from Thomas Preud'homme <thopre01 at gcc dot gnu.org> ---
Sadly I could not come up with a minimal testcase so far. What I can see from
the code is that tree code hoisting increases the live range of some values
which then translates into more spilling in reload.

As an approximation I'm wondering if the maximum distance (computer in number
of blocks traversed) from the definition to the use could be used to limit when
the optimization is applied when optimizing for speed.