[Bug rtl-optimization/72855] Long compile time due to integrity checking during dataflow analysis per loop

[wschmidt at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=72855

--- Comment #10 from Bill Schmidt <wschmidt at gcc dot gnu.org> ---
Some experiments on trunk:

- Using Bin's patch, I see compile time reduced to ~14 minutes.
- Using Richi's patch, I see compile time reduced to ~9 minutes.

So both are quite helpful compared to somewhere around 2 hours.

I'll plan to implement the pre-approved patch, but first I want to try to dig
into why flag_checking appears to have an unexpected value.