https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64928
--- Comment #11 from Richard Biener <rguenth at gcc dot gnu.org> --- Ok, so it's already calculate_live_ranges that takes much memory. I have a small patch to improve that somewhat. But what we really need is to get the "must coalesce" stuff "coalesced" with respect to both live and conflict computation. That is, map must-coalesce SSA vars to the same partition. That loses the SSA corruption testing, but well so it might be much more controversical (silent wrong-code instead of ICE). Unfortunately in the testcase there are only 2750 must-coalesces but 109493 partitions participating in the coalescing (so at least 50000 want coalesces). The good news is of course that we can simply choose to _not_ coalesce that many variables, but say only the important ones.
