[Bug c/57635] New: gcc hanging while compiling huge files

[Bug c/57635] New: gcc hanging while compiling huge files

[vijunag at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57635

            Bug ID: 57635
           Summary: gcc hanging while compiling huge files
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vijunag at gmail dot com

to gcc
Hello,

I recently upgraded my compiler to 4.7.2 and I'm trying to compile a huge file
containing as much as 92840 lines and gcc is taking an eternity to compile.
(more than 18 hours)

I see via top command that CC1 is consuming 100 percent CPU.

 PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND             
14848 vinag     25   0  485m 413m 8196 R 99.9  0.4  64:41.24 cc1     

I tried to attach to CC1 in gdb and below are few snapshots of it under gdb

snapshot 1
Program received signal SIGINT, Interrupt.
0x000000000052f775 in find_base_term ()
(gdb) bt
#0  0x000000000052f775 in find_base_term ()
#1  0x000000000052f924 in find_base_term ()
#2  0x000000000052fa45 in base_alias_check ()
#3  0x0000000000531823 in true_dependence_1 ()
#4  0x0000000000531a31 in canon_true_dependence ()
#5  0x00000000005acf58 in cselib_invalidate_mem ()
#6  0x00000000005ad14c in cselib_invalidate_rtx ()
#7  0x00000000005ad170 in cselib_invalidate_rtx_note_stores ()
#8  0x0000000000816458 in note_stores ()
#9  0x00000000005ad935 in cselib_record_sets ()
#10 0x00000000005add94 in cselib_process_insn ()
#11 0x0000000000a4b78a in vt_initialize ()
#12 0x0000000000a4beda in variable_tracking_main_1 ()
#13 0x0000000000a4be47 in variable_tracking_main ()
#14 0x00000000007a6b89 in execute_one_pass ()
#15 0x00000000007a6ef8 in execute_pass_list ()
#16 0x00000000007a6f16 in execute_pass_list ()
#17 0x00000000007a6f16 in execute_pass_list ()
#18 0x00000000008ddc76 in tree_rest_of_compilation ()
#19 0x00000000005a0a28 in cgraph_expand_function ()
#20 0x00000000005a0be4 in cgraph_expand_all_functions ()
#21 0x00000000005a14f0 in cgraph_optimize ()
#22 0x000000000059f498 in cgraph_finalize_compilation_unit ()
#23 0x000000000049d927 in c_write_global_declarations ()
#24 0x000000000087865e in compile_file ()
#25 0x000000000087a8e7 in do_compile ()
#26 0x000000000087aa34 in toplev_main ()
#27 0x000000000052a17f in main ()
(gdb) c
Continuing.

snapshot2
(gdb) bt
#0  0x000000000052f7ea in find_base_term ()
#1  0x000000000052f924 in find_base_term ()
#2  0x000000000052f7cf in find_base_term ()
#3  0x000000000052f924 in find_base_term ()
#4  0x000000000052fa45 in base_alias_check ()
#5  0x0000000000531823 in true_dependence_1 ()
#6  0x0000000000531a31 in canon_true_dependence ()
#7  0x00000000005acf58 in cselib_invalidate_mem ()
#8  0x00000000005ad14c in cselib_invalidate_rtx ()
#9  0x00000000005ad170 in cselib_invalidate_rtx_note_stores ()
#10 0x0000000000816458 in note_stores ()
#11 0x00000000005ad935 in cselib_record_sets ()
#12 0x00000000005add94 in cselib_process_insn ()
#13 0x0000000000a4b78a in vt_initialize ()
#14 0x0000000000a4beda in variable_tracking_main_1 ()
#15 0x0000000000a4be47 in variable_tracking_main ()
#16 0x00000000007a6b89 in execute_one_pass ()
#17 0x00000000007a6ef8 in execute_pass_list ()
#18 0x00000000007a6f16 in execute_pass_list ()
#19 0x00000000007a6f16 in execute_pass_list ()
#20 0x00000000008ddc76 in tree_rest_of_compilation ()
#21 0x00000000005a0a28 in cgraph_expand_function ()
#22 0x00000000005a0be4 in cgraph_expand_all_functions ()
#23 0x00000000005a14f0 in cgraph_optimize ()
#24 0x000000000059f498 in cgraph_finalize_compilation_unit ()
#25 0x000000000049d927 in c_write_global_declarations ()
#26 0x000000000087865e in compile_file ()
#27 0x000000000087a8e7 in do_compile ()
#28 0x000000000087aa34 in toplev_main ()
#29 0x000000000052a17f in main ()

I'm little bit surprised because same file I was able to compile with my older
gcc compiler 3.3.

i686-pc-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=~/tools/bintools/linux-x86/gcc/201302221200/bin/i686-pc-linux-gnu-gcc-wrapped
COLLECT_LTO_WRAPPER=~/tools/bintools/linux-x86/gcc/201302221200/libexec/gcc/i686-pc-linux-gnu/4.7.2/lto-wrapper
Target: i686-pc-linux-gnu
Configured with: ../../gcc/configure --build=amd64-pc-linux-gnu
--host=amd64-pc-linux-gnu --target=i686-pc-linux-gnu --enable-languages=c,c++
--prefix=~tools/bintools/linux-x86/gcc/201302221200 --enable-shared
--with-headers=/tmp/201302221200/new_header/ --disable-libquadmath
--disable-libgomp --disable-libssp --disable-libmudflap --disable-libitm
--with-fast-fixincludes --enable-threads --site=starent --with-gnu-as
--with-gnu-ld
Thread model: posix
gcc version 4.7.2 (GCC)


i586-pc-linux-gnu-gcc -c ternary.c
i586-pc-linux-gnu-gcc -v
Reading specs from
~/tools/bintools/linux-x86/gcc/200608191248/lib/gcc-lib/i586-pc-linux-gnu/3.3.6/specs
Configured with: ../../gcc/configure --build=i686-linux --host=i686-linux
--target=i586-pc-linux-gnu --enable-languages=c,c++
--prefix=~/tools/bintools/linux-x86/gcc/200608191248 --enable-shared
--with-headers=/localdisk/tmp/x86-linux/include --with-fast-fixincludes
--enable-threads --site=starent --with-gnu-as --with-gnu-ld
Thread model: posix
gcc version 3.3.6

[Bug c/57635] gcc hanging while compiling huge files

[vijunag at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57635

--- Comment #1 from vijay Nag <vijunag at gmail dot com> ---
Let me know if you will need any additional information. It is also difficult 
to isolate one single huge file from my project to attach it here. It will be
great if you can suggest me to proceed in some direction to debug this issue.

[Bug rtl-optimization/57635] gcc hanging while compiling huge files

[vijunag at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57635

--- Comment #2 from vijay Nag <vijunag at gmail dot com> ---
With the compiler flag "-fno-var-tracking", it compiles in less than a minute.
Although it is quite conspicuous from back-trace I thought it is worth
mentioning this info.

[Bug rtl-optimization/57635] gcc hanging while compiling huge files

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57635

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING
   Last reconfirmed|                            |2014-01-20
     Ever confirmed|0                           |1

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
We need some kind of a testcase for this, like preprocessed source of the file
exhibiting the issue.