[Bug bootstrap/68404] [6 Regression] PGO/LTO bootstrap failure on ppc64le

[wschmidt at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68404

--- Comment #10 from Bill Schmidt <wschmidt at gcc dot gnu.org> ---
Looking at scan_rtx_address () in regrename.c, it indeed looks like a PLUS
nested inside a PLUS isn't handled.  I'm not sure if this is a deficiency in
regrename.c, or whether the definition of fusion_gpr_load_di is just playing
with fire here.  Richard S., do you have an opinion?

fusion_gpr_load_di will not be present through most of the back end passes,
because it is introduced during peephole2.  So it seems like we'd probably be
ok just adding some more handling to regrename, but I'd like to hear other
opinions.