Using head from today to build a telecom stack on the ARM port.
It spends nearly 100% of time in tree call clobbering for a particularly nasty
testcase which I am attaching.
Almost every time I do a Ctrl-C in gdb I hit myself in the function
set_initial_properties with a similar backtrace.
. #0 0x0847f0da in var_ann (t=0xb6f433c8)
at ../../gnu/gcc/tree-flow-inline.h:204
#1 0x0847eee5 in mark_call_clobbered (var=0xb6f433c8, escape_type=256)
at ../../gnu/gcc/tree-flow-inline.h:878
#2 0x08480ce6 in set_initial_properties (ai=0x8a8b280)
at ../../gnu/gcc/tree-ssa-alias.c:565
#3 0x08481198 in compute_call_clobbered (ai=0x8a8b280)
at ../../gnu/gcc/tree-ssa-alias.c:619
in the hunk
if (TREE_CODE (alias) == STRUCT_FIELD_TAG)
{
subvar_t svars;
svars = get_subvars_for_var (SFT_PARENT_VAR (alias));
for (; svars; svars = svars->next)
if (!unmodifiable_var_p (alias))
mark_call_clobbered (svars->var, pi->escape_mask);
}
else if (!unmodifiable_var_p (alias))
mark_call_clobbered (alias, pi->escape_mask);
I tried by reverting the patch from r127629 but that didn't help straight off.
Doing a binary search I got to the versions r127831-37 :
r127831 is the last revision of the tree that builds this testcase without any
compile time regressions.
r127836 is the first revision of the tree where this goes awry with a huge
compile time regression .
versions (r127832-35) do not build for undeclared references to
forbidden_auto_inc_dec_classes in regclass.c. I haven't yet seen what's gone
into these commits to make any informed decisions.
This is the statistic with the
garbage collection : 0.43 ( 0%) usr 0.03 ( 0%) sys 4.51 ( 0%) wall
0 kB ( 0%) ggc
callgraph construction: 0.01 ( 0%) usr 0.00 ( 0%) sys 0.05 ( 0%) wall
69 kB ( 0%) ggc
callgraph optimization: 0.00 ( 0%) usr 0.00 ( 0%) sys 0.01 ( 0%) wall
51 kB ( 0%) ggc
ipa type escape : 0.01 ( 0%) usr 0.00 ( 0%) sys 0.01 ( 0%) wall
0 kB ( 0%) ggc
cfg cleanup : 0.02 ( 0%) usr 0.00 ( 0%) sys 0.01 ( 0%) wall
2 kB ( 0%) ggc
CFG verifier : 0.03 ( 0%) usr 0.00 ( 0%) sys 0.04 ( 0%) wall
0 kB ( 0%) ggc
trivially dead code : 0.00 ( 0%) usr 0.00 ( 0%) sys 0.01 ( 0%) wall
0 kB ( 0%) ggc
df live regs : 0.02 ( 0%) usr 0.00 ( 0%) sys 0.01 ( 0%) wall
0 kB ( 0%) ggc
df live&initialized regs: 0.02 ( 0%) usr 0.00 ( 0%) sys 0.02 ( 0%) wall
0 kB ( 0%) ggc
df use-def / def-use chains: 0.00 ( 0%) usr 0.01 ( 0%) sys 0.01 ( 0%)
wall 0 kB ( 0%) ggc
df reg dead/unused notes: 0.02 ( 0%) usr 0.00 ( 0%) sys 0.03 ( 0%) wall
19 kB ( 0%) ggc
register information : 0.01 ( 0%) usr 0.00 ( 0%) sys 0.00 ( 0%) wall
0 kB ( 0%) ggc
alias analysis : 0.00 ( 0%) usr 0.00 ( 0%) sys 0.02 ( 0%) wall
88 kB ( 0%) ggc
preprocessing : 0.13 ( 0%) usr 0.04 ( 0%) sys 0.19 ( 0%) wall
1636 kB ( 4%) ggc
lexical analysis : 0.05 ( 0%) usr 0.10 ( 1%) sys 0.09 ( 0%) wall
0 kB ( 0%) ggc
parser : 0.22 ( 0%) usr 0.09 ( 1%) sys 0.39 ( 0%) wall
7237 kB (19%) ggc
inline heuristics : 0.04 ( 0%) usr 0.00 ( 0%) sys 0.18 ( 0%) wall
325 kB ( 1%) ggc
integration : 0.01 ( 0%) usr 0.00 ( 0%) sys 0.00 ( 0%) wall
91 kB ( 0%) ggc
tree CFG cleanup : 0.02 ( 0%) usr 0.00 ( 0%) sys 0.06 ( 0%) wall
3 kB ( 0%) ggc
tree VRP : 0.04 ( 0%) usr 0.00 ( 0%) sys 1.11 ( 0%) wall
338 kB ( 1%) ggc
tree copy propagation : 0.01 ( 0%) usr 0.00 ( 0%) sys 0.07 ( 0%) wall
20 kB ( 0%) ggc
tree PTA : 0.06 ( 0%) usr 0.00 ( 0%) sys 0.11 ( 0%) wall
123 kB ( 0%) ggc
tree alias analysis : 0.53 ( 0%) usr 0.00 ( 0%) sys 1.27 ( 0%) wall
23 kB ( 0%) ggc
tree call clobbering :3604.47 (100%) usr 12.38 (95%) sys4166.01 (99%) wall
0 kB ( 0%) ggc
tree flow sensitive alias: 0.01 ( 0%) usr 0.00 ( 0%) sys 0.04 ( 0%) wall
150 kB ( 0%) ggc
tree flow insensitive alias: 0.54 ( 0%) usr 0.00 ( 0%) sys 0.73 ( 0%)
wall 0 kB ( 0%) ggc
tree memory partitioning: 1.91 ( 0%) usr 0.04 ( 0%) sys 3.32 ( 0%) wall
2 kB ( 0%) ggc
tree SSA rewrite : 0.00 ( 0%) usr 0.00 ( 0%) sys 0.27 ( 0%) wall
338 kB ( 1%) ggc
tree SSA incremental : 0.21 ( 0%) usr 0.00 ( 0%) sys 0.30 ( 0%) wall
17 kB ( 0%) ggc
tree operand scan : 1.96 ( 0%) usr 0.04 ( 0%) sys 4.16 ( 0%) wall
507 kB ( 1%) ggc
dominator optimization: 0.58 ( 0%) usr 0.00 ( 0%) sys 0.78 ( 0%) wall
234 kB ( 1%) ggc
tree SRA : 0.00 ( 0%) usr 0.00 ( 0%) sys 0.12 ( 0%) wall
1 kB ( 0%) ggc
tree CCP : 0.01 ( 0%) usr 0.00 ( 0%) sys 0.04 ( 0%) wall
17 kB ( 0%) ggc
tree reassociation : 0.00 ( 0%) usr 0.00 ( 0%) sys 0.17 ( 0%) wall
11 kB ( 0%) ggc
tree PRE : 0.15 ( 0%) usr 0.00 ( 0%) sys 0.23 ( 0%) wall
192 kB ( 1%) ggc
tree FRE : 0.04 ( 0%) usr 0.00 ( 0%) sys 0.42 ( 0%) wall
113 kB ( 0%) ggc
tree code sinking : 0.00 ( 0%) usr 0.00 ( 0%) sys 0.18 ( 0%) wall
5 kB ( 0%) ggc
tree forward propagate: 0.00 ( 0%) usr 0.00 ( 0%) sys 0.07 ( 0%) wall
40 kB ( 0%) ggc
tree conservative DCE : 0.01 ( 0%) usr 0.00 ( 0%) sys 0.01 ( 0%) wall
0 kB ( 0%) ggc
tree loop bounds : 0.01 ( 0%) usr 0.00 ( 0%) sys 0.01 ( 0%) wall
4 kB ( 0%) ggc
tree iv optimization : 0.00 ( 0%) usr 0.00 ( 0%) sys 0.01 ( 0%) wall
38 kB ( 0%) ggc
tree loop init : 0.00 ( 0%) usr 0.00 ( 0%) sys 0.08 ( 0%) wall
12 kB ( 0%) ggc
tree SSA to normal : 0.00 ( 0%) usr 0.00 ( 0%) sys 0.52 ( 0%) wall
31 kB ( 0%) ggc
tree SSA verifier : 4.07 ( 0%) usr 0.27 ( 2%) sys 5.43 ( 0%) wall
99 kB ( 0%) ggc
tree STMT verifier : 0.18 ( 0%) usr 0.00 ( 0%) sys 0.22 ( 0%) wall
0 kB ( 0%) ggc
dominance computation : 0.02 ( 0%) usr 0.00 ( 0%) sys 0.02 ( 0%) wall
0 kB ( 0%) ggc
expand : 0.96 ( 0%) usr 0.06 ( 0%) sys 9.88 ( 0%) wall
25260 kB (66%) ggc
forward prop : 0.01 ( 0%) usr 0.00 ( 0%) sys 0.01 ( 0%) wall
32 kB ( 0%) ggc
CSE : 0.06 ( 0%) usr 0.01 ( 0%) sys 0.46 ( 0%) wall
18 kB ( 0%) ggc
dead code elimination : 0.00 ( 0%) usr 0.01 ( 0%) sys 0.01 ( 0%) wall
0 kB ( 0%) ggc
dead store elim1 : 0.01 ( 0%) usr 0.00 ( 0%) sys 0.10 ( 0%) wall
17 kB ( 0%) ggc
dead store elim2 : 0.01 ( 0%) usr 0.00 ( 0%) sys 0.01 ( 0%) wall
24 kB ( 0%) ggc
loop analysis : 0.00 ( 0%) usr 0.00 ( 0%) sys 0.01 ( 0%) wall
15 kB ( 0%) ggc
CPROP 1 : 0.01 ( 0%) usr 0.00 ( 0%) sys 0.00 ( 0%) wall
15 kB ( 0%) ggc
PRE : 0.00 ( 0%) usr 0.00 ( 0%) sys 0.14 ( 0%) wall
6 kB ( 0%) ggc
CPROP 2 : 0.00 ( 0%) usr 0.00 ( 0%) sys 0.11 ( 0%) wall
15 kB ( 0%) ggc
bypass jumps : 0.02 ( 0%) usr 0.00 ( 0%) sys 0.00 ( 0%) wall
14 kB ( 0%) ggc
auto inc dec : 0.00 ( 0%) usr 0.00 ( 0%) sys 0.01 ( 0%) wall
7 kB ( 0%) ggc
CSE 2 : 0.04 ( 0%) usr 0.00 ( 0%) sys 0.07 ( 0%) wall
8 kB ( 0%) ggc
combiner : 0.02 ( 0%) usr 0.00 ( 0%) sys 0.38 ( 0%) wall
37 kB ( 0%) ggc
regmove : 0.03 ( 0%) usr 0.00 ( 0%) sys 0.04 ( 0%) wall
2 kB ( 0%) ggc
scheduling : 0.04 ( 0%) usr 0.00 ( 0%) sys 0.24 ( 0%) wall
39 kB ( 0%) ggc
local alloc : 0.06 ( 0%) usr 0.00 ( 0%) sys 0.06 ( 0%) wall
98 kB ( 0%) ggc
global alloc : 0.04 ( 0%) usr 0.00 ( 0%) sys 0.26 ( 0%) wall
35 kB ( 0%) ggc
reload CSE regs : 0.03 ( 0%) usr 0.00 ( 0%) sys 0.13 ( 0%) wall
52 kB ( 0%) ggc
thread pro- & epilogue: 0.01 ( 0%) usr 0.00 ( 0%) sys 0.00 ( 0%) wall
34 kB ( 0%) ggc
peephole 2 : 0.00 ( 0%) usr 0.00 ( 0%) sys 0.02 ( 0%) wall
0 kB ( 0%) ggc
rename registers : 0.03 ( 0%) usr 0.00 ( 0%) sys 0.06 ( 0%) wall
0 kB ( 0%) ggc
scheduling 2 : 0.07 ( 0%) usr 0.00 ( 0%) sys 0.10 ( 0%) wall
7 kB ( 0%) ggc
machine dep reorg : 0.00 ( 0%) usr 0.00 ( 0%) sys 0.02 ( 0%) wall
4 kB ( 0%) ggc
final : 0.03 ( 0%) usr 0.00 ( 0%) sys 0.74 ( 0%) wall
0 kB ( 0%) ggc
symout : 0.00 ( 0%) usr 0.00 ( 0%) sys 0.22 ( 0%) wall
0 kB ( 0%) ggc
TOTAL :3617.35 13.09 4205.33
38504 kB
--
Summary: tree struct aliasing goes into a loop marking call
clobbers.
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: ramana dot radhakrishnan at celunite dot com
GCC build triplet: i686-linux-gnu
GCC host triplet: i686-linux-gnu
GCC target triplet: arm-none-eabi
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33508
