[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