[Bug middle-end/18938] Out of memory with many select case statements
--- Comment #4 from tkoenig at gcc dot gnu dot org 2007-02-17 21:43 ---
This appears to have been fixed in the meantime:
$ perl multi-case-c 30 > multi-case.c
(reverse-i-search)`g': gcc multi-case.c
$ gdb ~/libexec/gcc/i686-pc-linux-gnu/4.3.0/cc1
GNU gdb 6.4.90-debian
Copyright (C) 2006 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB. Type "show warranty" for details.
This GDB was configured as "i486-linux-gnu"...Using host libthread_db library
"/lib/tls/i686/cmov/libthread_db.so.1".
(gdb) r multi-case.c
Starting program: /home/ig25/libexec/gcc/i686-pc-linux-gnu/4.3.0/cc1
multi-case.c
Failed to read a valid object file image from memory.
main {GC 222958k -> 184399k} {GC 274901k -> 263773k}
Execution times (seconds)
garbage collection: 4.16 ( 5%) usr 0.02 ( 1%) sys 4.22 ( 5%) wall
0 kB ( 0%) ggc
cfg cleanup : 1.83 ( 2%) usr 0.00 ( 0%) sys 1.84 ( 2%) wall
0 kB ( 0%) ggc
CFG verifier : 18.25 (24%) usr 0.11 ( 3%) sys 18.53 (23%) wall
0 kB ( 0%) ggc
trivially dead code : 0.37 ( 0%) usr 0.00 ( 0%) sys 0.36 ( 0%) wall
0 kB ( 0%) ggc
life analysis : 2.12 ( 3%) usr 0.01 ( 0%) sys 2.17 ( 3%) wall
0 kB ( 0%) ggc
life info update : 0.82 ( 1%) usr 0.01 ( 0%) sys 0.85 ( 1%) wall
0 kB ( 0%) ggc
alias analysis: 0.35 ( 0%) usr 0.00 ( 0%) sys 0.36 ( 0%) wall
0 kB ( 0%) ggc
register scan : 0.15 ( 0%) usr 0.00 ( 0%) sys 0.16 ( 0%) wall
0 kB ( 0%) ggc
rebuild jump labels : 0.30 ( 0%) usr 0.00 ( 0%) sys 0.30 ( 0%) wall
0 kB ( 0%) ggc
preprocessing : 1.41 ( 2%) usr 0.54 (14%) sys 2.39 ( 3%) wall
11181 kB ( 3%) ggc
lexical analysis : 0.48 ( 1%) usr 1.45 (36%) sys 1.72 ( 2%) wall
0 kB ( 0%) ggc
parser: 8.32 (11%) usr 0.94 (24%) sys 9.34 (11%) wall
73956 kB (17%) ggc
inline heuristics : 2.21 ( 3%) usr 0.13 ( 3%) sys 2.35 ( 3%) wall
0 kB ( 0%) ggc
tree gimplify : 3.80 ( 5%) usr 0.02 ( 1%) sys 4.11 ( 5%) wall
17283 kB ( 4%) ggc
tree eh : 0.29 ( 0%) usr 0.01 ( 0%) sys 0.30 ( 0%) wall
0 kB ( 0%) ggc
tree CFG construction : 2.01 ( 3%) usr 0.09 ( 2%) sys 2.10 ( 3%) wall
127713 kB (29%) ggc
tree CFG cleanup : 1.63 ( 2%) usr 0.01 ( 0%) sys 1.63 ( 2%) wall
0 kB ( 0%) ggc
tree STMT verifier: 7.36 (10%) usr 0.26 ( 7%) sys 7.82 (10%) wall
0 kB ( 0%) ggc
callgraph verifier: 0.10 ( 0%) usr 0.00 ( 0%) sys 0.10 ( 0%) wall
0 kB ( 0%) ggc
expand: 7.56 (10%) usr 0.12 ( 3%) sys 7.79 ( 9%) wall
166651 kB (38%) ggc
jump : 0.37 ( 0%) usr 0.00 ( 0%) sys 0.37 ( 0%) wall
0 kB ( 0%) ggc
flow analysis : 0.54 ( 1%) usr 0.01 ( 0%) sys 0.55 ( 1%) wall
0 kB ( 0%) ggc
mode switching: 0.04 ( 0%) usr 0.00 ( 0%) sys 0.04 ( 0%) wall
0 kB ( 0%) ggc
local alloc : 1.71 ( 2%) usr 0.00 ( 0%) sys 1.68 ( 2%) wall
0 kB ( 0%) ggc
global alloc : 6.35 ( 8%) usr 0.11 ( 3%) sys 6.81 ( 8%) wall
42188 kB (10%) ggc
flow 2: 0.79 ( 1%) usr 0.00 ( 0%) sys 0.79 ( 1%) wall
1 kB ( 0%) ggc
final : 3.23 ( 4%) usr 0.09 ( 2%) sys 3.45 ( 4%) wall
0 kB ( 0%) ggc
TOTAL : 76.56 3.9982.20
439966 kB
Extra diagnostic checks enabled; compiler may run slowly.
Configure with --disable-checking to disable checks.
Program exited normally.
Closing.
--
tkoenig at gcc dot gnu dot org changed:
What|Removed |Added
Status|NEW |RESOLVED
Resolution||FIXED
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18938
[Bug middle-end/18938] Out of memory with many select case statements
--- Additional Comments From Thomas dot Koenig at online dot de 2004-12-12
10:42 ---
(In reply to comment #2)
> Speculations I'd put money on if the bookies would accept it:
> 1) You can show this same problem with C/C++ if you have enough cases.
Yes.
$ time ./multi-case-c 15 > multi-case.c
$ gcc multi-case.c
cc1: out of memory allocating 2815331376 bytes after a total of 10571776 bytes
$ gcc -v
Reading specs from /home/ig25/lib/gcc/i686-pc-linux-gnu/4.0.0/specs
Configured with: ../gcc/configure --prefix=/home/ig25
--enable-languages=c,c++,f95
Thread model: posix
gcc version 4.0.0 20041208 (experimental)
$ cat multi-case-c
#! /usr/bin/perl
$last = shift;
for ($i=1; $i<=$last; $i++) {
push(@lines, sprintf("case %d:\n j = %d;\nbreak;\n", $i,
$last-$i));
}
for ($i=0; $i<=$last; $i++) {
$j = int(rand($last));
$temp = $lines[$i];
$lines[$i] = $lines[$j];
$lines[$j] = $temp;
}
print <
int main()
{
int i,j;
scanf("%d",&i);
switch(i) {
EOF
print @lines;
print <
int main()
{
int i,j;
scanf("%d",&i);
switch(i) {
case 2:
j = 2;
break;
case 4:
j = 0;
break;
case 3:
j = 1;
break;
case 1:
j = 3;
break;
}
printf("%d\n",i);
return 0;
This isn't a regression, gcc 3.3 had the same problem:
$ /usr/bin/gcc multi-case.c
cc1: out of memory allocating 2815312608 bytes after a total of 18419712 bytes
$ /usr/bin/gcc -v
Reading specs from /usr/lib/gcc-lib/i486-linux/3.3.5/specs
Configured with: ../src/configure -v
--enable-languages=c,c++,java,f77,pascal,objc,ada,treelang --prefix=/usr
--mandir=/usr/share/man
--infodir=/usr/share/info--with-gxx-include-dir=/usr/include/c++/3.3
--enable-shared --with-system-zlib --enable-nls --without-included-gettext
--enable-__cxa_atexit --enable-clocale=gnu --enable-debug --enable-java-gc=boehm
--enable-java-awt=xlib --enable-objc-gci486-linux
Thread model: posix
gcc version 3.3.5 (Debian 1:3.3.5-3)
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18938
[Bug middle-end/18938] Out of memory with many select case statements
--- Additional Comments From steven at gcc dot gnu dot org 2004-12-11 21:57 --- Speculations I'd put money on if the bookies would accept it: 1) You can show this same problem with C/C++ if you have enough cases. 2) No compiler can support 2416101224 basic blocks -- but why do we have so many of them?? -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18938
[Bug middle-end/18938] Out of memory with many select case statements
--- Additional Comments From pinskia at gcc dot gnu dot org 2004-12-11 17:24 --- Confirmed, but the problem is not in the front-end this time :). #4 0x0027c298 in sbitmap_vector_alloc (n_vecs=2416101224, n_elms=17) at /Users/pinskia/ src/local3/gcc/gcc/sbitmap.c:160 #5 0x002ea824 in make_edges (min=0x9002c768, max=0x51350200, update_p=1) at /Users/ pinskia/src/local3/gcc/gcc/cfgbuild.c:247 #6 0x002eaf84 in find_many_sub_basic_blocks (blocks=0x1) at /Users/pinskia/src/local3/gcc/gcc/ cfgbuild.c:697 #7 0x002b4878 in tree_expand_cfg () at /Users/pinskia/src/local3/gcc/gcc/cfgexpand.c:1322 -- What|Removed |Added Status|UNCONFIRMED |NEW Component|fortran |middle-end Ever Confirmed||1 Keywords||memory-hog Last reconfirmed|-00-00 00:00:00 |2004-12-11 17:24:54 date|| http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18938
