[Bug middle-end/18927] O(n^2) compile time with -O0 (n= number of basic blocks) in local alloc

[heinrich dot brand at fujitsu-siemens dot com]

------- Additional Comments From heinrich dot brand at fujitsu-siemens dot com  2004-12-13 11:37 -------
 My compiler outputs really this line:
 global alloc          :1083.72 (99%) usr   0.39 (51%) sys1085.19 (99%) wall

Line with context:

hei@pgtd2308:~/CCS/GLOBALALLOC/04> /home/hei/GCCBIN/3.4.3/bin/gcc -S -O0 -v -
ftime-report z.c
Lese Spezifikationen von /home/hei/GCCBIN/3.4.3/lib/gcc/i686-pc-linux-
gnu/3.4.3/specs
Konfiguriert mit: ../gcc-3.4.3/configure -prefix /home/hei/GCCBIN/3.4.3 --
enable-checking
Thread-Modell: posix
gcc-Version 3.4.3
 /home/hei/GCCBIN/3.4.3/libexec/gcc/i686-pc-linux-gnu/3.4.3/cc1 -quiet -v z.c -
quiet -dumpbase z.c -mtune=pentiumpro -auxbase z -O0 -version -ftime-report -o 
z.s
nicht vorhandenes Verzeichnis »/home/hei/GCCBIN/3.4.3/lib/gcc/i686-pc-linux-
gnu/3.4.3/../../../../i686-pc-linux-gnu/include« wird ignoriert
#include "..." - Suche beginnt hier:
#include <...> - Suche beginnt hier:
 /usr/local/include
 /home/hei/GCCBIN/3.4.3/include
 /home/hei/GCCBIN/3.4.3/lib/gcc/i686-pc-linux-gnu/3.4.3/include
 /usr/include
Ende der Suchliste.
GNU C version 3.4.3 (i686-pc-linux-gnu)
        compiled by GNU C version 3.2.
GGC-Heuristik: --param ggc-min-expand=30 --param ggc-min-heapsize=4096
    
Ausführungszeiten (Sekunden)
 garbage collection    :   1.27 ( 0%) usr   0.00 ( 0%) sys   1.27 ( 0%) wall
 cfg construction      :   0.56 ( 0%) usr   0.00 ( 0%) sys   0.56 ( 0%) wall
 cfg cleanup           :   0.17 ( 0%) usr   0.00 ( 0%) sys   0.17 ( 0%) wall
 trivially dead code   :   0.26 ( 0%) usr   0.00 ( 0%) sys   0.26 ( 0%) wall
 life analysis         :   0.98 ( 0%) usr   0.00 ( 0%) sys   0.98 ( 0%) wall
 life info update      :   0.43 ( 0%) usr   0.00 ( 0%) sys   0.43 ( 0%) wall
 register scan         :   0.49 ( 0%) usr   0.03 ( 4%) sys   0.52 ( 0%) wall
 rebuild jump labels   :   0.31 ( 0%) usr   0.00 ( 0%) sys   0.31 ( 0%) wall
 preprocessing         :   0.20 ( 0%) usr   0.05 ( 6%) sys   0.24 ( 0%) wall
 lexical analysis      :   0.26 ( 0%) usr   0.09 (12%) sys   0.36 ( 0%) wall
 parser                :   0.89 ( 0%) usr   0.05 ( 6%) sys   0.95 ( 0%) wall
 expand                :   1.22 ( 0%) usr   0.05 ( 6%) sys   1.27 ( 0%) wall
 jump                  :   0.07 ( 0%) usr   0.00 ( 0%) sys   0.07 ( 0%) wall
 flow analysis         :   0.35 ( 0%) usr   0.01 ( 1%) sys   0.36 ( 0%) wall
 local alloc           :   2.50 ( 0%) usr   0.06 ( 8%) sys   2.56 ( 0%) wall
 global alloc          :1083.72 (99%) usr   0.39 (51%) sys1085.19 (99%) wall
 flow 2                :   0.96 ( 0%) usr   0.00 ( 0%) sys   0.96 ( 0%) wall
 shorten branches      :   0.94 ( 0%) usr   0.01 ( 1%) sys   0.95 ( 0%) wall
 final                 :   1.25 ( 0%) usr   0.03 ( 4%) sys   1.37 ( 0%) wall
 rest of compilation   :   2.50 ( 0%) usr   0.00 ( 0%) sys   2.50 ( 0%) wall
 GESAMT                :1099.35             0.77          1101.32
hei@pgtd2308:~/CCS/GLOBALALLOC/04> 


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18927