http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60291
--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
remove_unused_locals is called from at least cfgcleanup-post-optimizing at -O0.
At -O0 I have (trunk)
expand : 481.98 (94%) usr 1.15 (17%) sys 481.94 (93%) wall
293891 kB (15%) ggc
TOTAL : 512.44 6.86 519.82
2023628 kB
so it's not that particular spot at -O0.
At -O1 it becomes dominant though:
expand : 36.83 (18%) usr 0.78 ( 8%) sys 37.18 (17%) wall
177246 kB ( 8%) ggc
remove unused locals : 122.09 (58%) usr 0.79 ( 8%) sys 122.80 (56%) wall
0 kB ( 0%) ggc
TOTAL : 210.18 9.30 219.40
2258487 kB
fixed by removing that walking of DECL_INITIAL. I'm sure somebody put
thought into it but I can't think of any case that would break with not
doing that walking. -O1 without that:
phase parsing : 5.50 ( 6%) usr 4.49 (48%) sys 9.98 (11%) wall
294905 kB (13%) ggc
expand : 34.99 (41%) usr 0.92 (10%) sys 36.44 (38%) wall
177246 kB ( 8%) ggc
integrated RA : 4.65 ( 5%) usr 0.29 ( 3%) sys 4.60 ( 5%) wall
478130 kB (21%) ggc
TOTAL : 85.57 9.39 94.92
2258487 kB
so probably the very same issue as with -O0.
