http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59659
Markus Trippelsdorf <trippels at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |trippels at gcc dot gnu.org
--- Comment #5 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #3)
> I think this is somewhat related to e.g.:
> struct A { A (); A (int); ~A (); };
> void bar (A *);
>
> #define T10(N) N, N, N, N, N, N, N, N, N, N
> #define T100(N) T10(N), T10(N), T10(N), T10(N), T10(N), \
> T10(N), T10(N), T10(N), T10(N), T10(N)
> #define T1000(N) T100(N), T100(N), T100(N), T100(N), T100(N), \
> T100(N), T100(N), T100(N), T100(N), T100(N)
> #define T10000(N) T1000(N), T1000(N), T1000(N), T1000(N), T1000(N), \
> T1000(N), T1000(N), T1000(N), T1000(N), T1000(N)
> #define T100000(N) T10000(N), T10000(N), T10000(N), T10000(N), T10000(N), \
> T10000(N), T10000(N), T10000(N), T10000(N), T10000(N)
>
> void
> foo ()
> {
> A a[] = { 1, 2, T1000 (3), T10000 (4), T1000 (3), 2, 1 };
> bar (a);
> }
>
> also taking long time to compile and generating enormous amount of code (and
> when replacing T10000 (4) with T100000 (4) it is even much worse).
I don't think they are directly related.
For your testcase clang is even slower than gcc (1:51min vs. 21.8sec).
perf report shows:
6.92% cc1plus cc1plus [.] get_value_for_expr(tree_node*, bool)
4.98% cc1plus cc1plus [.] canonicalize_value(prop_value_d*)
3.56% cc1plus cc1plus [.] mark_used_flags(rtx_def*, int)
3.01% cc1plus cc1plus [.] ccp_visit_phi_node(gimple_statement_base*)
2.97% cc1plus cc1plus [.] redirect_eh_edge_1(edge_def*, basic_block_def*,
bool)
2.87% cc1plus cc1plus [.] remove_eh_landing_pad(eh_landing_pad_d*)
2.86% cc1plus cc1plus [.] vrp_meet(value_range_d*, value_range_d*)
On the testcase from Mark (with array size 10000) clang is much
faster (0.7sec vs. 15.7sec) and perf report shows that the multiplication in
get_ref_base_and_extent is mostly responsible:
9.95% cc1plus cc1plus [.] get_ref_base_and_extent(tree_node*, long*,
long*, long*)
7.94% cc1plus cc1plus [.] mul_double_wide_with_sign(unsigned long, long,
unsigned long, long, unsigned long*, long*, unsigned long*, long*, bool)
7.40% cc1plus cc1plus [.] hash_table<vn_reference_hasher,
xcallocator>::find_slot_with_hash(vn_reference_s const*, unsigned int,
insert_option)
4.22% cc1plus cc1plus [.] component_ref_field_offset(tree_node*)
4.18% cc1plus cc1plus [.] record_store(rtx_def*, bb_info*)
3.81% cc1plus cc1plus [.] hash_table_mod2(unsigned int, unsigned int)
3.59% cc1plus cc1plus [.] array_ref_low_bound(tree_node*)
