[Bug target/99104] [11 Regression] ICE: Segmentation fault (in bitmap_list_find_element)

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99104

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Well, at least if split() does not maintain DF then split patterns may not use
DF.  It's as simple as that ;)  Note you need DF analyze anyway since even
if present, the DF problem might be out-of-date.

Note when you add DF_LIVE you have to remove it manually again if optimize == 1
because there we do not maintain it (but the problem is still not optional).

I guess if the x86 backend wants to use DF but other backends do not and do
not want to pay the compile-time cost of a df_analyze we could put DF
setup into a target hooks hand ... (or a target hook returning the DF problems
it likes to have computed for split).