https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97623
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |ASSIGNED
Ever confirmed|0 |1
Summary|Extremely slow O2 compile |[9/10/11 Regression]
|(>>O(n^2)) |Extremely slow O2 compile
| |(>>O(n^2))
Known to work| |7.5.0
Component|middle-end |tree-optimization
Last reconfirmed| |2020-10-29
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
tree PRE : 6.83 ( 96%) 0.02 ( 50%) 6.90 ( 96%)
11764 kB ( 37%)
Confirmed.
insert iterations == 187: 1
RPO blocks: 843
RPO iterations == 10: 1
compute_antic iterations == 2: 1
RPO blocks visited: 843
New PHIs: 15021
RPO num values == 7009: 1
Insertions: 23846
RPO max_rpo iterations == 0: 1
RPO blocks executable: 843
RPO block visited times == 1: 843
HOIST inserted: 13098
RPO num lattice == 7009: 1
RPO num avail == 6755: 1
Symbol to SSA rewrite: 1
Eliminated: 27807
So the number of insert iterations is troubling.
Now the testcase is a bit big to analyze what's going on there, we seem
to need about 2 insert iterations for each of the statements.
It looks like the statements are 1:1 copies besides sometimes changing
the constant index into the tbt__rvtop__swerv__ifu__bp__bht_bank_wr_data
array?
I will have a closer look.
