[Bug middle-end/17520] New: [regression] Huge compile time for C code

["arend dot bayer at web dot de" <gcc-bugzilla at gcc dot gnu dot org>]

Compiling the attached file with GCC 4.0.0 as of 04-09-15 takes over 70 
seconds, compared to 0.6 seconds with 3.4.2. It also needs over 250MB of RAM. 
 
Appended is the output of gcc -v -ftime-report -O2 -c slow.c -save-temps. 
 
Reading specs from /usr/local/gcc-3.5/lib/gcc/i686-pc-linux-gnu/4.0.0/specs 
Configured with: ../gcc/configure --disable-checking --enable-languages=c 
--prefix=/usr/local/gcc-3.5 
Thread model: posix 
gcc version 4.0.0 20040915 (experimental) 
 /usr/local/gcc-3.5/libexec/gcc/i686-pc-linux-gnu/4.0.0/cc1 -E -quiet -v slow.c 
-mtune=pentiumpro -ftime-report -O2 -fpch-preprocess -o slow.i 
ignoring nonexistent directory 
"/usr/local/gcc-3.5/lib/gcc/i686-pc-linux-gnu/4.0.0/../../../../i686-pc-linux-gnu/include" 
#include "..." search starts here: 
#include <...> search starts here: 
 /usr/local/include 
 /usr/local/gcc-3.5/include 
 /usr/local/gcc-3.5/lib/gcc/i686-pc-linux-gnu/4.0.0/include 
 /usr/include 
End of search list. 
 
Execution times (seconds) 
 TOTAL                 :   0.00             0.00             0.01 
 /usr/local/gcc-3.5/libexec/gcc/i686-pc-linux-gnu/4.0.0/cc1 -fpreprocessed 
slow.i -quiet -dumpbase slow.c -mtune=pentiumpro -auxbase slow -O2 -version 
-ftime-report -o slow.s 
GNU C version 4.0.0 20040915 (experimental) (i686-pc-linux-gnu) 
        compiled by GNU C version 4.0.0 20040915 (experimental). 
GGC heuristics: --param ggc-min-expand=64 --param ggc-min-heapsize=64421 
 
Execution times (seconds) 
 garbage collection    :   0.03 ( 0%) usr   0.00 ( 0%) sys   0.24 ( 0%) wall 
 life analysis         :   0.00 ( 0%) usr   0.00 ( 0%) sys   0.01 ( 0%) wall 
 tree gimplify         :   0.00 ( 0%) usr   0.00 ( 0%) sys   0.01 ( 0%) wall 
 tree CFG construction :   0.01 ( 0%) usr   0.00 ( 0%) sys   0.00 ( 0%) wall 
 dominator optimization:   0.01 ( 0%) usr   0.00 ( 0%) sys   0.01 ( 0%) wall 
 tree PRE              :   0.00 ( 0%) usr   0.00 ( 0%) sys   0.01 ( 0%) wall 
 tree DSE              :   0.02 ( 0%) usr   0.00 ( 0%) sys   0.00 ( 0%) wall 
 tree iv optimization  :  42.78 (58%) usr   0.28 (42%) sys  47.96 (58%) wall 
 expand                :   0.00 ( 0%) usr   0.00 ( 0%) sys   0.01 ( 0%) wall 
 loop analysis         :   0.01 ( 0%) usr   0.00 ( 0%) sys   0.01 ( 0%) wall 
 CPROP 1               :   0.01 ( 0%) usr   0.00 ( 0%) sys   0.00 ( 0%) wall 
 CPROP 2               :   0.00 ( 0%) usr   0.00 ( 0%) sys   0.01 ( 0%) wall 
 CSE 2                 :   0.01 ( 0%) usr   0.00 ( 0%) sys   0.00 ( 0%) wall 
 branch prediction     :  30.59 (42%) usr   0.39 (58%) sys  33.79 (41%) wall 
 local alloc           :   0.01 ( 0%) usr   0.00 ( 0%) sys   0.01 ( 0%) wall 
 peephole 2            :   0.01 ( 0%) usr   0.00 ( 0%) sys   0.00 ( 0%) wall 
 rename registers      :   0.00 ( 0%) usr   0.00 ( 0%) sys   0.01 ( 0%) wall 
 TOTAL                 :  73.50             0.67            82.10 
 as -V -Qy -o slow.o slow.s 
GNU assembler version 2.15.90.0.1.1 (i586-suse-linux) using BFD version 
2.15.90.0.1.1 20040303 (SuSE Linux)

-- 
           Summary: [regression] Huge compile time for C code
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: arend dot bayer at web dot de
                CC: gcc-bugs at gcc dot gnu dot org
  GCC host triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17520