https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98863
--- Comment #39 from rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> --- Just to give an update on this: I have a patch that reduces the amount of memory consumed by fwprop so that it no longer seems to be outlier. However, it involves doing more bitmap operations. In this testcase we have a larger number of registers that seem to be live but unused across a large region of code, so bitmap ANDs with the live in sets are expensive and hit the worst-case O(nblocks×nregisters). I'm still trying to find a way of reducing the effect of that.
