https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63384
--- Comment #1 from Andi Kleen <andi-gcc at firstfloor dot org> ---
With a newer compiler version
gcc version 5.0.0 20140926 (experimental) (GCC)
the test case doesn't crash anymore, but just runs very very long. I killed it
after 20s. This happens with the following two options:
g++50 matrix.i -o outfile -O2 -fvar-tracking-assignments-toggle
-fselective-scheduling2
The overhead is mostly in the scheduler:
- sched_analyze_insn(deps_desc*, rtx_def*, rtx_insn*) ▒
- 99.39% deps_analyze_insn(deps_desc*, rtx_insn*) ▒
tick_check_p(_expr*, deps_desc*, _fence*) ▒
fill_insns(_fence*, int, _list_node***) ▒
sel_sched_region_2(int) ▒
sel_sched_region(int) ▒
run_selective_scheduling() ▒
(anonymous namespace)::pass_sched2::execute(function*) ▒
execute_one_pass(opt_pass*) ▒
execute_pass_list_1(opt_pass*) ▒
execute_pass_list_1(opt_pass*) ▒
execute_pass_list_1(opt_pass*) ▒
execute_pass_list(function*, opt_pass*) ▒
cgraph_node::expand() ▒
symbol_table::compile() ▒
symbol_table::finalize_compilation_unit() ▒
cp_write_global_declarations() ▒
compile_file() ▒
toplev_main(int, char**) ▒
__libc_start_main ▒
+ 0.61% tick_check_p(_expr*, deps_desc*, _fence*)
sched_analyze_insn(deps_desc*, rtx_def*, rtx_insn*)
│
│ for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
12.84 │ 748: add $0x1,%r13d
0.07 │ add $0x30,%r14
│ cmp $0x4d,%r13d
│ ↓ je 7e5
│ if (TEST_HARD_REG_BIT (implicit_reg_pending_uses, i))
0.06 │ 75a: mov %r13d,%eax
12.45 │ shr $0x6,%eax
0.17 │ mov 0x1828100(,%rax,8),%rax
6.06 │ bt %r13,%rax
6.21 │ ↑ jae 748
│ {
